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Large carnivore menus: factors affecting hunting decisions by cheetahs in the Serengeti
Abstract
Predation plays a key role in shaping mammalian communities through prey killed and through the decisions and choices of both predators and prey. We used an extensive data set from observed hunts of a diurnal large African carnivore, the cheetah, Acinonyx jubatus, in combination with analysis techniques originally developed in the field of economics (discrete choice models) to examine predation decisions within the context of the immediate environment and the reproductive and hunger status of individuals. This is one of the first attempts at an integrated understanding of the suite of ecological and behavioural factors that influence hunting decisions in a large carnivore. The decision of a cheetah to hunt or not was influenced by the abundance of their main prey, the reproductive status of the cheetah and the presence of competitors and predators, but not by the hunger level of the cheetah. Given that the decision to hunt is taken, prey choice is then driven by the time of year, the sex of the predator, the abundance of prey and the presence of competitors. We believe that discrete choice models may provide a new step forward in our ability to understand the decisions that animals make in their natural environment.
... The main factors that influenced the cheetah's initiation of a hunt in the Serengeti NP were the abundance of their main prey species and the abundance of lions. The presence of Thomson's gazelles in medium-sized groups (approximately 135 animals) increased the likelihood that a cheetah initiated a hunt (compared to larger or smaller groups of gazelles), whereas the presence of lions decreased the likelihood of a hunt being initiated (Cooper et al., 2007). Further, when females had cubs, they were more likely to initiate a hunt compared to females without cubs, probably because the former have a higher demand on energy (Cooper et al., 2007). ...
... The presence of Thomson's gazelles in medium-sized groups (approximately 135 animals) increased the likelihood that a cheetah initiated a hunt (compared to larger or smaller groups of gazelles), whereas the presence of lions decreased the likelihood of a hunt being initiated (Cooper et al., 2007). Further, when females had cubs, they were more likely to initiate a hunt compared to females without cubs, probably because the former have a higher demand on energy (Cooper et al., 2007). ...
... The reasons why a hunt is successful or not, is thought to be a complex interplay between the hunting skills of the individual cheetah, including its age and condition, its ability to approach close enough to the prey before chasing it, the prey species being hunted, and the habitat (hilborn et al., 2012;Mills et al., 2017). hunting success is not influenced by the hunger level of the cheetah, nor does hunger level influence the decision to initiate a hunt (Cooper et al., 2007;hilborn et al., 2012). When hunting gazelle fawns, cheetahs are more successful when fawns run away as compared to when they drop down to hide (Fitzgibbon, 1990a). ...
Cheetahs have unique social and mating systems, as well as hunting techniques. Males are either territory holders defending small territories or floaters roaming in large, overlapping, undefended home ranges. Both spatial tactics are adopted by solitary males or coalitions of males. Females are solitary unless accompanied by offspring. They give birth to two to six cubs, which are hidden in a lair for the first 2 months. In ecosystems with other large predator species, cheetahs adopt several predator avoidance behaviors. Nevertheless, cubs can suffer from high mortality by lions and spotted hyenas, and adult cheetahs may lose kills to kleptoparasites. Cheetahs primarily hunt abundant, small to medium sized prey animals using high-speed chases over short distances. They mainly communicate with vocalization and olfaction, often using prominent landmarks for scent marking. Given the increasing human pressure on carnivores, conservation efforts would benefit from behavioral data in human inhabited areas.
... Investigations of prey selectivity in felids were mostly based on selectivity indices that compare prey taken with prey availability and opportunism was defined as taking prey relative to its availability (e.g., Chesson, 1978;Manly, 2002). Most studies limit their assessment of prey availability to estimates or indices of relative prey abundance (e.g., Karanth and Sunquist, 1995;Novack et al., 2005; but see Cooper et al., 2007). ...
... As all prey species investigated here, as well as jaguars, were predominantly nocturnal-crepuscular (data not shown), we did not consider the temporal aspect further. Line transects are the usual method to determine prey abundance in predator diet studies (Cooper et al., 2007). The nocturnal, cryptic and wide ranging habit of the large mammals and the small size of small mammals make this method unfeasible for jaguar prey species in ENP. ...
... On the other hand, their large and aggressive groups pose a serious risk of injury to jaguars and they may also profit from increased vigilance (Pulliam, 1973;Lipetz and Beckoff, 1982). For both cheetahs and lions, a preference for smaller groups of prey has been reported (Scheel, 1993;Cooper et al., 2007). ...
... to account for what and when animals hunt based on characteristics of the prey and nonconsummatory 'satisfaction' from prey acquisition (Cooper et al. 2007). These models, nevertheless, make predictions about animal foraging decisions based on maximizing reward. ...
... These early models for the optimal forager made unrealistic assumptions about animal cognitive capacities when considering the ability of animals to estimate patch quality, weigh energetic costs of seeking and acquiring food and identify energetic gain with near perfect accuracy to produce an optimal foraging strategy (Shettleworth 2001;Andersen et al. 2006). More recent models incorporate measures of memory and decision processing by combining optimal foraging theory with theories of behavioural timing (e.g.'Scalar Expectancy Theory'-- Kacelnik & Brunner 2002), or utilize discrete choice models, to account for what and when animals hunt based on characteristics of prey and predator and non-consummatory 'satisfaction' from prey acquisition (Cooper et al. 2007). These models, nevertheless, make predictions about animal foraging decisions based on maximizing reward. ...
... The alternative is that motivation for contrafreeloading by grizzly bears is less affected by physiological needs than predicted, a finding that would correspond with studies of carnivores where that the decision whether or not to hunt is independent of hunger level (e.g. cheetahs, Cooper et al. 2007). ...
... Therefore, compared to solitary females, we also predicted that mothers with cubs would have more successful hunts on medium and large prey due to more successful chases. Hunger level does not determine whether a cheetah starts a hunt (Cooper et al. 2007), but it may influence whether a cheetah gives up on a stalk, as a hungry cheetah may be more likely to complete a stalk and commit to the effort of a chase than a sated individual. Thus, we tested whether hungry cheetah have more successful stalks. ...
... Increased hunting success has been suggested as a reason for habitat selection by predators (Gorini et al. 2012), and Serengeti cheetah preferentially use rivers and rocky outcroppings called kopjes (Pettorelli et al. 2009). The added cover and elevation of kopjes may provide an advantage to hunting cheetah, but recent evidence does not support this (Cooper et al. 2007), suggesting that cheetah select kopjes for reasons other than hunting. We tested whether distance from kopje affects stalk, chase or overall hunt success. ...
... We modelled the likelihood of (1) a stalk to turn into a chase (2) a chase to end in a kill and (3) an overall hunt to be successful. We limited our analysis to hunts by females as there are differences in prey choice and ranging patterns between the sexes (Caro 1994;Cooper et al. 2007) and limited hunt data were available for males. Since our response variables were binomial, and since we wished to correct for pseudoreplication (multiple hunts by the same cheetah), we used generalized linear mixed effects models with binomial errors, including the identity of the cheetah as a random effect in all models considered. ...
Predation is a complex behavioural process and it is only through identifying the different factors influencing each stage that is it possible to understand the evolutionary processes driving the arms race between predators and prey. Using a long-term data set from Serengeti National Park in Tanzania, we investigated the importance of demographic, environmental, and prey-based factors in influencing the success of hunt stages of a stalking predator, the cheetah, Acinonyx jubatus. The chase and overall hunting success were influenced by the age of the cheetah and prey size, while the effect of habitat features could only be seen in the stalk. Whether a stalk turned into a chase was dependent on prey size, and in the dry season on proximity to rivers. Contrary to expectation, the hunger level of the cheetah, the presence of cubs, and the type of habitat where the hunt took place had no effect on hunting success. Different factors thus affect the success of individual hunt stages, and the predation risk of prey is influenced not only by its size, the habitat it is in, and the age of the its predator, but also by hunt stage. This reveals an increased complexity of predation risk that has implications for predator and prey dynamics, especially in systems with multiple predator and prey species.
... Caro [1994] reported that 25%, 11%, and 29% of failed hunts in solitary, paired and trios of male cheetahs on the Serengeti respectively, were as a result of them "not being serious" about the hunt. Cooper et al. [2007] emphasized that the decision to hunt is not based upon hunger in cheetahs. This suggests that motivation to hunt plays an important role. ...
... This suggests that motivation to hunt plays an important role. Cooper et al. [2007] also noted that males tended to select for larger prey than females. It is possible that, on occasion, males in the current study were less inclined to initiate high speed "hunts" as a result of decreased motivation to pursue the relatively small "prey" item. ...
... Each run enclosure provided similar areas of cover in the form of shrubs, bushes, and trees. Cooper et al. [2007] reported that cover availability had no influence on decisions to hunt in cheetahs. In contrast, the size of the run enclosure was an important factor. ...
The enrichment practice of the "cheetah run" is becoming increasingly popular within zoological institutions as a method to enrich captive cheetahs. A lure moving at speed represents an artificial prey item that the cursorial cheetah can pursue, therefore allowing it to perform an important hunting behavior within a captive setting. This study was conducted in order to highlight how employing different forms of this type of enrichment may influence its efficacy. This is important in relation to the future development of an optimum type of "cheetah run" enrichment which maximizes the potential beneficial effects and therefore positively impacts upon cheetah welfare in captivity. Video recordings were carried out at three separate institutions (Fota Wildlife Park, Ireland; Ann van Dyk Cheetah Centre, South Africa; Cheetah Conservation Fund, Namibia). Randomization tests were carried out to compare the highest speeds attained between males and females, trained and untrained cheetahs and also between the three institutions. Females and trained individuals reached significantly higher speeds compared with males and untrained individuals, respectively. The only significant difference between the three institutions was between the Ann van Dyk Cheetah Centre and the Cheetah Conservation Fund, where cheetahs at the Ann van Dyk center reached significantly higher speeds. The current study represents the first detailed study of any aspect of the "cheetah run" across multiple institutions. It also includes the first quantification of the speed of cheetahs in captivity in relation to differing enrichment practices. Zoo Biol. XX:XX-XX, 2013. © 2013 Wiley Periodicals, Inc.
... Feline predators are particularly flexible, exploitative, and opportunistic. Cheetahs (Acinonyx jubatus) vary in prey selection based on sex (Cooper et al. 2007), mountain lion (Puma concolor) on reproductive status and age (Ross et al. 1997), and domestic cats (Felis catus) on sex and body size (Kutt 2012;Moseby et al. 2015). ...
... This opposing trend may relate to the smaller body size of females enabling them to obtain sufficient protein from invertebrates, whereas larger males require more protein and thus might target larger prey. Intraspecific differences in diet are found in other carnivores that vary in prey selection according to sex (e.g., cheetahs and domestic cats; Cooper et al. 2007;Moseby et al. 2015), age (cougars; Ross et al. 1997), and body size (domestic cats; Kutt 2012; Moseby et al. 2015). ...
Predator diet can be influenced by competition and intraguild predation, leading to resource partitioning and/or avoidance. For sympatric, endemic predators, these processes form as predator species coevolve, facilitating coexistence. However, when novel predator interactions occur, significant dietary overlap could create acute levels of competition leading to intraguild predation and population extinction, or accelerated changes in diet and/or spatial and temporal avoidance. We measured diet, intraguild predation, and spatial and temporal overlap in two predator species in a novel predator interaction: the western quoll (Dasyurus geoffroii), a small, native carnivore reintroduced to semi-arid Australia, and the domestic cat (Felis catus), a larger introduced carnivore already resident at the release site. Both species exhibited high dietary overlap and fed on mammals, reptiles, birds, and invertebrates. Cats included quolls in their diet. Quoll diet was broader (including carrion, bats, and plant material) and flexible, changing significantly with age, sex, and season. Introduced rabbit was the most common prey item recorded for both species (frequency of occurrence = 40–50%). However, quolls consumed rabbits in relation to their availability while rabbit consumption in cats was unrelated to availability suggesting a stronger dependence on rabbit prey. Quoll diet did not change over time since release and they did not spatially or temporally avoid cats. However, cats were significantly spatially associated with rabbits while quolls were not, suggesting higher predation efficacy in quolls possibly due to their smaller body size enabling them to catch rabbits inside warrens. Despite high dietary overlap and intraguild predation, the quoll’s broad and flexible diet and high predation efficacy appeared to assist in facilitating coexistence and reducing competition in this novel predator interaction. This dietary flexibility may be harnessed to improve conservation outcomes: reducing introduced rabbits in our study area could naturally reduce feral cat populations while having less impact on native quolls.
... Unfortunately, the influence of individual predator traits on predation impacts has received less focus (but see Funston & Mille, 2006), despite studies reporting intraspecific differences in predation impacts related to predator sex (Marlow et al., 2015), age (Litvaitis, Clark & Hunt, 1986), experience (Estes et al., 2003) and body size (Kutt, 2012;Moseby et al., 2015). Feline predators are particularly flexible, exploitative and opportunistic, Cheetahs Acinonyx jubatus vary in prey selection based on sex (Cooper, Pettorelli & Durant, 2007), Lynx Lynx lynx on reproductive status (Pierce, Bleich & Bowyer, 2000), Cougars Puma concolor on age (Ross, Jalkotzy & Festa-Bianchet, 1997) and domestic cats Felis catus on sex and body size (Kutt, 2012;Moseby et al., 2015). Individual felines can also specialize on certain prey based on individual experience and learn to hunt difficult prey (Knopff & Boyce, 2007;Dickman & Newsome, 2015;Moseby et al., 2015). ...
... Sex is another phenotypic characteristic that has been shown to affect individual predation rates in weasels Mustela nivalis (Sundell, 2003), Cheetahs Acinonyx jubatus (Cooper et al., 2007) and wolf spiders Pardosa vancouveri (Hardman & Turnbull, 1974). However, sex only weakly influenced rabbit consumption when body mass was held constant. ...
Globally, wildlife managers often control predator populations to protect biodiversity, livestock or other valued resources. Most assume that the predation impact of each individual predator is the same and that removing any individual predator produces a benefit to the target species. However, research suggests predation efficacy can vary within a predator species according to phenotypic characteristics. Understanding these individual differences may be critical for managing predation impacts on particular categories of prey including small populations where predation effects are amplified. We used dietary data from 1748 feral cats euthanized over 30 years during a control programme in arid Australia to determine whether any predator attributes could predict their effect on different prey weight classes. Feral cats in our study ate a wide range of prey including reptiles, mammals, birds and invertebrates. Demography (body mass) was a highly significant predictor of diet. Cats weighing 3 kg fed predominantly on prey <50 g increasing to >500 g when cats attained a body mass of 6 kg. Of more significance was that diet varied between demographic groups but also within a single demographic group (adult males) based on body mass, with results having significant implications for threatened prey. Modelling indicated that for a fixed predator population size, the predation rate on prey in a >500 g weight class increased by 28% when the ratio of large (>4.2 kg) to small adult males varied according to its natural range (12%–80% over the 30‐year study). Results suggest that variations in predator demography can significantly impact predation rates on prey species and should be included in predator–prey models for small prey populations. On average, large male cats comprised 23% of the population and our findings suggest that targeting this ‘lethal demographic’ and manipulating predator demography should be prioritized along with lowering predator density to reduce predation impacts on prey weighing more than 500g.
... Because high levels of activity, presumably hunts, may increase body temperature, we hypothesized that cheetahs may shift to a nocturnal activity pattern to avoid hyperthermia during hot periods, without compromising total 24-h activity. In addition, because hunger does not appear to be the trigger for cheetah hunts (Cooper et al. 2007), we hypothesized that hunts occur when cheetahs are otherwise active. Ongoing locomotor activity could affect a cheetah's readiness for the intense activity of a chase (Wilson et al. 2013). ...
... That explanation would not fit with the seasonal changes in activity that we observed; for example, we have no reason to believe that cheetahs were hungrier between 0900 and 1500 hours in the cool-dry seasonal period than at the same time in other seasonal periods, but they were more active then. Similarly, the hunger level of cheetahs in east Africa did not influence their decision to hunt (Cooper et al. 2007). It seems as if the cheetahs would attempt to hunt if they came across potential prey while they were active. ...
As one of the few felids that is predominantly diurnal, cheetahs (Acinonyx jubatus Von Schreber, 1775) can be exposed to high heat loads in their natural habitat. Little is known about long‐term patterns of body temperature and activity (including hunting) in cheetahs because long‐term concurrent measurements of body temperature and activity never have been reported for cheetahs, or indeed for any free‐living felid. We report here body temperature and locomotor activity measured with implanted data loggers over seven months in five free‐living cheetahs in Namibia. Air temperature ranged from a maximum of 39ºC in summer to −2ºC in winter. Cheetahs had higher (∼0.4 ºC) maximum 24h body temperatures, later acrophase (∼1 h), with larger fluctuations in the range of the 24h body temperature rhythm (∼0.4 ºC) during a hot‐dry period than during a cool‐dry period, but maintained homeothermy irrespective of the climatic conditions. As ambient temperatures increased, the cheetahs shifted from a diurnal to a crepuscular activity pattern, with reduced activity between 9:00 and 15:00 and increased nocturnal activity. The timing of hunts followed the general pattern of activity; the cheetahs hunted when they were on the move. Cheetahs hunted if an opportunity presented itself, on occasion they hunted in the midday heat or in total darkness (new moon). Biologging revealed insights into cheetah biology that are not accessible by traditional observer‐based techniques.
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... However, fine-scale avoidance requires the ability to react appropriately and rapidly to changes in current risk, which can negatively affect foraging behavior. For example, the proximity of larger carnivores lowers the chances that cheetahs will initiate a hunt (Durant 1998(Durant , 2000aCooper et al. 2007). Once a hunt has begun, moving to avoid larger carnivores would involve abandoning a kill or losing opportunities to hunt prey, and therefore may not be the optimal reaction to short-term changes in risk. ...
... In order to reduce the chances of encountering large predators while hunting, mesopredators can avoid hunting when predators are nearby (Durant 1998;Cooper et al. 2007), or they can preferentially forage when the predators are less active (Harrington et al. 2009;Mukherjee et al. 2009). However, once prey are caught, there are other behaviors a mesopredator can use to lower the risks of predation and kleptoparasitism. ...
While handling large kills, mesocarnivores are particularly vulnerable to kleptoparasitism and predation from larger predators. We used 35 years of observational data on cheetah (Acinonyx jubatus) hunts in Serengeti National Park to investigate whether cheetahs’ prey handling behavior varied in response to threats from lions (Panthera leo) and spotted hyenas (Crocuta crocuta). Male cheetahs and single females, whose main threat was kleptoparasitism, minimized time on the kill by being less vigilant and eating quickly, thereby shortening their handling times. Mothers with cubs showed a different strategy that prioritized vigilance over speed of eating, which increased time spent handling prey. Vigilance allowed them to minimize the risk of their cubs being killed while giving cubs the time they need to eat at the carcass. Flexible behavioral strategies that minimize individual risk while handling prey likely allow mesocarnivores to coexist with numerous and widespread apex predators.
Significance statement
Medium-sized carnivores like cheetahs face the challenge of coexisting with larger carnivores that steal their kills and kill their cubs. We investigated how cheetahs modify their behavior on kills to minimize risks from larger predators. Using 35 years of data on 400+ cheetah hunts across 159 individuals, we found that cheetahs without cubs whose primary danger is having their kill stolen spent little time engaged in vigilance and instead ate quickly, reducing the risk of theft. Mothers with cubs, however, took a slower approach and were more vigilant while handling prey to avoid cub predation by lions and spotted hyenas. The ability of cheetahs to modify their prey handling behavior depending on the type of risk they face likely allows them to coexist with numerous larger carnivores.
... Previous studies have shown that cheetah foraging behaviour is influenced by the abundance of prey and the presence of competitors but that the time of day had no influence (Cooper et al. 2007). This, however, only refers to diurnal foraging as observations on cheetahs are predominantly carried out during the day (Cooper et al. 2007, Hilborn et al. 2012 Biggs 1993, Hayward and and are therefore unable to show trends associated with long-term cycles such as the moon and season. ...
... Previous studies have shown that cheetah foraging behaviour is influenced by the abundance of prey and the presence of competitors but that the time of day had no influence (Cooper et al. 2007). This, however, only refers to diurnal foraging as observations on cheetahs are predominantly carried out during the day (Cooper et al. 2007, Hilborn et al. 2012 Biggs 1993, Hayward and and are therefore unable to show trends associated with long-term cycles such as the moon and season. However, with the development of data-loggers that automatically record and store animal activity in the absence of human observers, it is possible to investigate behaviours that have previously not been observed. ...
Intraguild competition and predation have been recognised as important ecological factors influencing the population dynamics of carnivores. The effects of these interactions are often asymmetrical due to a size-related dominancy hierarchy. However, it has been suggested that competitively subordinate carnivores can minimise the costs of predation and competition through spatial and temporal avoidance. Here I investigate the ecological and behavioural mechanisms by which cheetahs (Acinonyx jubatus) coexist with competitively stronger lions (Panthera leo) and spotted hyaenas (Crocuta crocuta). Fieldwork was carried out in the Okavango Delta, northern Botswana, between October 2008 and August 2011. A total of 20 Global Positioning System (GPS) radio-collars were fitted on all known cheetahs (n=6), lion prides (n=5) and spotted hyaena clans (n=6) in the study area (approx. 3 000 km2). Pre-programmed radio-collars recorded locations and activity continuously for each individual and these data were complemented with direct behavioural observations. Cheetah data were analysed with respect to the temporal and spatial likelihood of encountering lions and spotted hyaenas. Results suggest that the response to the risks posed by other predators is species-specific, habitat-specific and dependent on the immediacy of the risk. Resource partitioning was not the main mechanism for coexistence as cheetahs overlapped extensively with lions and spotted hyaenas in time, space and habitat use. Instead, cheetahs adjusted their spatial distribution in response to immediate risks or adapted their habitat use depending on their vulnerability (e.g. behaviours such as feeding or with differing levels of moonlight at night). In general, cheetah temporal and spatial distribution is a hierarchical process, firstly driven by resource acquisition and thereafter fine-tuned by predator avoidance. In addition, habitat heterogeneity seemed to be key in facilitating coexistence. Understanding the behavioural mechanisms that interacting apex predators adopt to regulate these negative interactions could be crucial to carnivore conservation, especially as human-related habitat loss is forcing species into ever smaller areas.
... However, when medium to large prey is not available, cheetahs are able to subsist on smaller prey. Outside of birth peaks of ungulates, springhares (Pedetidae capensis) and hares (Leporidae) were the most frequently eaten species on Namibian farmlands as determined by scat analysis (Marker et al., 2003b;Wachter et al., 2006), and in Tanzania as determined by observations (Cooper et al., 2007). Similarly, using data from direct observations and tracking spoor, Mills (2015) found that in the southern Kalahari most cheetah kills (except for coalition males) fell outside the prey range, identified by Hayward et al. (2006), with many kills comprising smaller prey, such as steenbok (Raphicerus campestris), springbok (Antidorcas marsupialis) lambs, hares, and springhares. ...
... As a consequence, in areas with abundant lion and spotted hyena populations cheetahs have higher mortality rates (Laurenson, 1994;Marker et al., 2003a;Wachter et al., 2011) and regions outside of protected areas, where lions and spotted hyenas have largely been eradicated, often support higher densities of cheetahs than protected areas . In protected areas with lions, cheetahs are most likely only able to persist through fine-scale avoidance mechanisms (Cooper et al., 2007;Mills, 2015;Swanson et al., 2014) by altering habitat use and activity patterns to avoid larger carnivores. In these areas, cheetahs may select hunting areas with less prey but more protective cover from competitors Broekhuis and Gopalaswamy, 2016;Durant, 2000;Rostro-García et al., 2015). ...
Considerable research has been conducted on cheetah ecology. Cheethas can exist in a wide variety of habitats from thick shrub to open grassland, and habitat selection is based on a variety of factors, including visibility, prey density, and avoidance of competitively superior predators. Cheetahs naturally occur at low densities and require a prey base of small to medium-sized ungulates that can be consumed rapidly, minimizing the risks for cheetahs of being detected by larger carnivores that can usurp their kills. Cheetahs exhibit wide ranging movements and large home ranges - over 2000 km2 in some areas. Reported densities range from 0.3 to 3.0 adult cheetahs per 100 km2. The species distribution, density, and activity patterns are impacted by human activities and the presence of larger carnivores. Understanding cheetah habitat requirements and movement ecology, epecially pertaining to long-distance movements, will become progressively more important as the cheetah's range becomes increasingly fragmented.
... Both orthogonality and equal representation of trait levels allow for choices made by individuals to be tied to specific traits (Louviere et al. 2010). DCMs without DCEs have been used previously by ecologists to study prey selection and habitat use as well as tradeoffs made with respect to habitat and prey traits (McCracken et al. 1998;Cooper & Millspaugh 1999;McDonald et al. 2006;Cooper et al. 2007). While DCEs have been extensively employed in consumer economics to construct trait-based experiments (Louviere et al. 2010), to our knowledge they have not yet been used in ecology. ...
... Of course other traits or variables can be considered post hoc in analysis. The results of these post hoc assessments then reflect an approach more like other observational DCMs (McCracken et al. 1998;Cooper & Millspaugh 1999;McDonald et al. 2006;Cooper et al. 2007). We used average trait values for each species in our analysis, which could produce misleading results if intraspecific variation in traits This article is protected by copyright. ...
Seeds of many hardwood trees are dispersed by scatter-hoarding rodents, and this process is often mediated by the traits of seeds. Although numerous studies have linked seed traits to seed preference by rodents, little is known about how rodents forage for seeds when multiple desirable and undesirable seed traits are available simultaneously. Here, we adopt a novel method of designing choice experiments to study how eastern gray squirrels (Sciurus carolinensis) select for 6 traits (caloric value, protein content, tannin concentration, kernel mass, dormancy period and toughness of shell) among seeds. From n=426 seed-pair presentations, we found that squirrels preferentially consumed seeds with short dormancy or tougher shells, and preferentially cached seeds with larger kernel mass, tougher shells and higher tannin concentrations. By incorporating random effects, we found that squirrels exhibited consistent preferences for seed traits, which is likely due to the fitness consequences associated with maintaining cached resources. Furthermore, we found that squirrels were willing to trade between multiple traits when caching seeds, which likely results in more seed species being cached in the fall. Ultimately, our approach allowed us to compute the relative values of different seed traits to squirrels, despite covariance among studied traits across seed species. Additionally, by investigating how squirrels trade among different seed traits, important insights can be gleaned into behavioral mechanisms underlying seed caching (and thus seed survival) dynamics as well as evolutionary strategies adopted by plants to attract seed dispersers. We describe how discrete choice experiments can be used to study resource selection in other ecological systems.
... Dietary preferences and prey selection for terrestrial carnivores have been widely investigated as they play a key role in shaping mammalian communities (Sih et al. 1985, Cooper et al. 2007. Several hypotheses have been proposed to explain prey selection by predators. ...
... These field studies have provided the most pertinent evidence for non-random prey selection (Curio 1976, Scheel 1993, Karanth and Sunquist 1995, Pole et al. 2004, Bodendorfer et al. 2006. Prey selection occurred at several levels, for example selectivity for prey species, prey size and age or sex classes, and selectivity towards physically substandard individuals (Karanth and Sunquist 1995, Woolnough and Carthew 1996, Pole et al. 2004, Cooper et al. 2007. ...
... A study conducted by Wegge et al. (2009) has contradicted the suggestion by Breuer (2005) and found that predation is highest among the most preferred prey independent of the density of such species. Cooper et al. (2007) stated that predation plays a key role in shaping mammalian communities by decisions and choices of both predators and prey species. Prey activity patterns, spatial distribution and availability can influence hunting success and prey selection (Fuller et al., 1992;Henschel & Skinner, 1990). ...
... Prey availability and the ecology of available prey species dictate the ecology of predators in a given area (Bakker, 1983;Kruuk, 1986;Henschel & Skinner, 1990;Fuller et al., 1992;Mills, 1992;Woodroffe, 2001;Ray et al., 2005;Cooper et al., 2007). ...
Conflict between livestock farmers and large carnivores has prevailed since the domestication of animals were first attempted by man. Inadequate information on predator dynamics, especially in regions outside formal protected areas where they are perceived as problem animals, render control methods arduous. The aim of this study was to explore the relationships between leopard Panthera pardus (Linnaeus, 1758) and brown hyena Parahyaena brunnea (Thunberg, 1820), their potential prey populations and its relevance to cattle losses in the Roodewalshoek Conservancy, Mpumalanga. This study was the first of its kind in this specific conflicted area. Assessment of utilization of the area by these large predators was conducted with the aid of digital motion-sensor camera traps, combined with field observations of any physical signs of these animals. During this study, 16 potential prey species (>2 kg) were recorded and peaks in circadian, monthly and lunar rhythms were unique to each species. A total of seven predatory species were recorded, also with unique circadian, monthly and lunar rhythms to each species. Small and large predators seemed to exhibit spatial and temporal separation and individual predators exhibited unique behavioural responses to their shared environment. Both leopards and brown hyaenas proved equally responsible for livestock losses, which increased from January 2005 to October 2010. Inter-predator competition was observed between these two species. The majority of calves were caught during low moonlight intensity and in the wet season. Both predators displayed surplus-killing behaviour. Even though sufficient occurrences of natural prey could be found in the Roodewalshoek Conservancy, predation on livestock persists during the calving season.
Keywords: leopard; brown hyaena; livestock losses; lunar; surplus-killing
... Carnivores as Dietary Generalists.-Carnivores will select their prey on the basis of prey availability, size, abundance, and catchability (Hayward and Kerley 2005;Balme et al. 2007;Cooper et al. 2007). Carnivores are able to change their preferred prey species as prey abundance or environmental conditions change (Bodendorfer et al. 2006). ...
... Similarly, in a woodland-dominated environment, carnivores will tend to prey on the more abundant browsing herbivores. Despite evidence for some species-specific dietary preferences among the African carnivore guild (e.g., Balme et al. 2007;Cooper et al. 2007), the ecological integrator model tends to hold true among living carnivores (Codron et al. 2007). In addition, Reed (1997) has demonstrated that modern carnivore-accumulated death assemblages can be used to faithfully reconstruct the vegetation types within the locality, irrespective of the habitats present or the accumulating carnivore species. ...
Fundamental to the interpretation of bone-bearing faunal deposits is an understanding of the taphonomic processes that have modified the once living fossil community. An often neglected source of bias is that of climate-averaging, which occurs when the duration of bone accumulation exceeds the duration of an individual climatic episode. Tropical and subtropical climate change is dominated by precessional cyclicity (∼21,000 year cycle), which controls monsoon rainfall intensity and thus plant communities over time. Under a climate-averaging scenario, the paleoecological characteristics of a faunal deposit represent an amalgamation of more than one phase of the precessional cycle. We investigate the degree of climate-averaging in Plio-Pleistocene bone breccias from South Africa by comparing stable isotope measurements of fossil enamel with the evidence from high-resolution speleothem paleoclimate proxies. We conclude that each of the four faunal assemblages studied are climate-averaged, having formed over a time period in excess of one-third of a precessional cycle (∼7000 years). This has implications for the reconstruction of hominin paleoenvironments and estimates of Plio-Pleistocene biodiversity. We hypothesize that climate-averaging may be a common feature of tropical terrestrial vertebrate assemblages throughout the Cenozoic and Mesozoic.
... In the wild, maternal food intake exceeding 1.5 kg per day is necessary to maintain adequate milk production for cub growth, while cub growth decreased when maternal intake fell below 1.5 kg per day, with no added benefit observed with higher intake levels (up to 5 kg per day) (Laurenson, 1995b). To sustain higher intake levels, cheetahs adjust their diet by hunting and targeting larger prey, which in turn increases the proportion of large prey killed (Cooper et al., 2007); lactating female cheetahs consume 65-97% more food compared to non-reproductive females. ...
This Standard Operating Procedure (SOP) outlines the essential criteria, actions, and precautions to be followed at the field level in cheetah introduction sites.
... This is particularly important for species where the reproductive success of one sex (typically females) directly relates to population persistence (e.g. An et al., 2021;Cooper et al., 2007;Thomas & Schultz, 2016). ...
While resource selection varies according to the scale and context of study, gathering data representative of multiple scales and contexts can be challenging especially when a species is small, elusive and threatened. We explored resource selection in a small, nocturnal, threatened species, the greater bilby, Macrotis lagotis, to test (1) which resources best predict bilby occupancy, and (2) whether responses are sex specific and/or vary over time. We tracked 20 bilbies and examined within home range resource selection over multiple seasons in a large (110 ha) fenced sanctuary in temperate Australia. We tested a set of plausible models for bilby resource selection, and found that food biomass (terrestrial and subterranean invertebrates and subterranean plants) and soil textures (% sand, clay and silt) best predicted bilby resource selection for all sampling periods. Selection was also sex specific: female resource use, relative to males, was more closely linked to the location of high-quality resources (invertebrate biomass). Bilby selection for roads was independent of season but varied over time with males selecting for areas closer to roads when plants increased in density off roads. Our findings demonstrate the importance of considering resource selection over multiple contexts and highlight a method to collect such data on a difficult to study, threatened species. Collecting such data is critical to understanding the habitat required by species.
... This research often fails to take into account ecological realities that, over time, may influence and constrain cognitive abilities in real-life decision-making. For example, prey availability and distribution can fluctuate across seasons, and predators must decide which species to hunt, whether to hunt or scavenge, and how to avoid interspecific competition and humans (Cooper et al. 2007;Pereira et al. 2013;Ordiz et al. 2017). Cognitive abilities such as enumerating and timing are central to many psychological and ecological models of behavior, yet our knowledge of how these are affected by environmental fluctuations remains incomplete. ...
Much research has focused on the development and evolution of cognition in the realm of numerical knowledge in human and nonhuman animals but often fails to take into account ecological realities that, over time, may influence and constrain cognitive abilities in real-life decision-making. Cognitive abilities such as enumerating and timing are central to many psychological and ecological models of behavior, yet our knowledge of how these are affected by environmental fluctuations remains incomplete. Our research bridges the gap between basic cognitive research and ecological decision-making. We used coyotes (Canis latrans) as a model animal system to study decision-making about smaller, more proximal food rewards and larger, more distant food rewards; we tested animals across their four reproductive cycle phases to examine effects of ecological factors such as breeding status and environmental risk on quantitative performance. Results show that coyotes, similar to other species, spatially discount food rewards while foraging. The degree to which coyotes were sensitive to the risk of obtaining the larger food reward, however, depended on the season in which they completed the foraging task, the presence of unfamiliar humans (i.e., risk), and the presence of conspecifics. Importantly, our results support that seasonal variations drive many differences in nonhuman animal behavior and cognition (e.g., hibernation, breeding, food resource availability). Further, it may be useful in the future to extend this work to humans because seasons may influence human cognition as well, and this remains unexplored in the realms of enumeration, timing, and spatial thinking.
... They take a wide variety of prey, principally small-to mid-sized ungulates, especially gazelle (Gazella spp.), kob (Kobus kob) and impala (Aepyceros melampus). But their prey can range from ground-dwelling birds and small mammals, such as hares, up to large ungulates such as wildebeest (Connochates taurinus), kudu (Tragelaphus strepciseros) or eland (Tragelaphus oryx) (Purchase and du Toit 2000, Broomhall et al. 2003, Mills et al. 2004, Cooper et al. 2007, Hilborn et al. 2012. In Iran opportunistic recovery of Cheetah kills and analysis of scat suggests that gazelle, wild sheep Ovis orientalis, Persian Ibex Capra aegagrus and Cape Hares Lepus capensis are key prey species (Khalatbari 2021, Farhadinia et al. 2012). ...
... Cheetahs also predate on livestock, including sheep, goat and camel 16,17 , although they primarily consume wild prey 15,18 . Prey choice depends on prey abundance, presence of competitors, and cheetah's sex 19 . Male coalitions are able to kill larger preys 20 , solitary females usually hunt smaller preys 13,21 , but when they have dependent cubs, they may take larger prey items 22 . ...
Knowledge on diet composition allows defining well-targeted conservation measures of large carnivores. Little is known about ecology of critically endangered Asiatic cheetah, especially the overall diet and its possible regional differences. We used cheetah scats, metabarcoding technique and microsatellite markers to assess the individual and overall diet composition of the species across its entire range in Asia. Cheetahs were primarily predating on mouflon; following by ibex, cape hare and goitered gazelle. Despite their high availability, small-sized livestock was never detected. Goitered gazelles were only detected in an area where the habitat is mainly flatlands. In hilly areas, mouflon was the most frequent prey item taken. Ibex was typically taken in rugged terrain, but mouflon was still the most frequently consumed item in these habitats. High consumption of mouflon in comparison to goitered gazelle suggests that human pressure on lowland habitats has possibly forced Asiatic cheetahs to occupy suboptimal habitats where gazelles are less abundant. The protection of flatlands and the removal of livestock from them are needed to ensure the long-term survival of Asiatic cheetah. The laboratory and bioinformatics pipelines used in this study are replicable and can be used to address similar questions in other threatened carnivores.
... Past research on the Namibian farmlands recorded spring hare (Pedetes capensis) and hares (Leporidae) as the most important cheetah prey item outside of birth peaks of ungulates (Marker et al., 2003(Marker et al., , 2018Wachter et al., 2006). In Eastern Africa, cheetahs prey on hares in Maasai Mara National Reserve in Kenya and Serengeti National Park in Tanzania, although in small proportions Cooper et al., 2007). Although hares were consumed, such small prey is insufficient to feed family TA B L E 2 Number of cheetah scats (out of 27 scat samples), which contained hairs from each prey item, the frequency of occurrence of prey from cheetah scats, and the relative abundance (%) of prey (out of 12,482 observations) assessed in the study area ...
The conversion of natural ecosystems due to anthropogenic activities has led to the destruction of natural habitats and to the deterioration of habitat quality. Top predators particularly respond sensitively to changes in habitat structures, including the availability of prey. The cheetah Acinonyx jubatus prefers small-medium-sized, wild ungulate prey due to the cheetah's morphological adaptations. However, the majority of the species' population is found beyond protected areas, where habitat structures, species abundances, and community composition are highly influenced by human activities. Only few studies have analyzed the diet preference of cheetahs in relation to prey availability and abundance for rangelands beyond protected areas in Eastern Africa. The study aimed to determine cheetah prey preference in the rangelands of south-eastern Kenya based on scat analyses. We compared dietary preference of cheetah with prey availability. For this purpose, we conducted standardized game counts. We analyzed 27 cheetah scat samples collected across the same study area where we also conducted game counts. We found that Grant's gazelle Gazella granti contributed the highest portion of cheetah's diet, although Thomson's gazelle Gazella thomsonii was the most abundant medium-sized ungulate prey in the study areas. We also recorded two primate species, yellow baboon Papio cynocephalus and vervet monkey Chlorocebus pygerythrus, as well as the rock hyrax Procavia capensis in the cheetah diet. These species have never been documented as cheetah prey before. Furthermore, our results document livestock as potential prey for cheetahs. These observations underline that cheetah use diverse prey in rangelands outside protected areas, and that the abundance of specific prey does not influence cheetah prey preference.
... Numerous factors related to the prey affect its ability to escape from the attack of predators, such as the animal species, age, sex and, in the case of species with defined hierarchical structures, the size of the social group [70,75]. Our results suggest that, among the range of prey dependent factors, only the prey species proved to be an influential factor in its probability of escape. ...
The individuals engaged in predation interactions modify their adaptation strategies to improve their efficiency to reach success in the fight for survival. This success is linked to either capturing prey (predator) or escaping (prey). Based on the graphic material available on digital platforms both of public and private access, this research aimed to evaluate the influence of those animal- and environment-dependent factors affecting the probability of successful escape of prey species in case of attack by big cats. Bayesian predictive analysis was performed to evaluate the outcomes derived from such factor combinations on the probability of successful escape. Predator species, age, status at the end of the hunting act, time lapse between first attention towards potential prey and first physical contact, prey species and the relief of the terrain, significantly conditioned (p < 0.05) escape success. Social cooperation in hunting may be more important in certain settings and for certain prey species than others. The most parsimonious model explained 36.5% of the variability in escaping success. These results can be useful to design translatable selective strategies not only seeking to boost predation abilities of domestic felids for pest control, but also, biological antipredator defence in potential domestic prey of big cats.
... Complete extinction of carnivores must be avoided because the predator-prey relationships which they drive are vital for ecosystem functioning and stability (Davies et al., 2016). The imbalances that can occur because of mismatched predator-to-prey ratios, or an absence of predators, have been found to cause major shifts in ecosystem functioning (Cooper et al., 2007;Davies et al., 2016). ...
African lions (Panthera leo) can influence the location, distribution and behaviour of smaller carnivores such as cheetahs (Acinonyx jubatus). In fenced protected areas, where space is limited, the effects of the apex predator can be exaggerated to the point of localized extinction of the subordinate. Here, we directly compare the prey selection of cheetahs before and after the re‐introduction of lions to the Mountain Zebra National Park, South Africa. The lion re‐introduction did not significantly influence the diet of the cheetahs. Greater kudu (Tragelaphus strepsiceros) and springbok (Antidorcas marsupialis) comprised >75% of cheetah diet both before and after the lion re‐introduction with no noticeable changes in the size ranges of prey selected. In addition, there was no significant dietary overlap (O < 0.45) with the lions. Our study supports recent findings that cheetahs, as subordinate predators, can coexist with larger, more aggressive carnivores within an enclosed environment without compromising access to resources. However, our work represents a temporal snapshot into lion and cheetah foraging behaviour in an enclosed system and we recommend further research across multiple sites and predator densities.
... Predatory behaviour provides a good opportunity to evaluate quantity discrimination. Appropriate decisionmaking in this context is of adaptive significance due to the often considerable time invested in tracking prey or to waiting in ambush and to the possible risk of injury versus nutritional gain (Werner and Hall 1974;Cooper et al. 2007;Panteleeva et al. 2013). Previous studies with amphibians tested with live prey support the theory that individuals should maximize food intake according to time and energy invested, and so if given the opportunity, should choose the larger quantity and size of prey (Uller et al. 2003;Krusche et al. 2010;Stancher et al. 2015). ...
Quantity discrimination is of adaptive relevance in a wide range of contexts and across a wide range of species. Trained domestic cats can discriminate between different numbers of dots, and we have shown that they also spontaneously choose between different numbers and sizes of food balls. In the present study we performed two experiments with 24 adult cats to investigate spontaneous quantity discrimination in the more naturalistic context of potential predation. In Experiment 1 we presented each cat with the simultaneous choice between a different number of live prey (1 white mouse vs. 3 white mice), and in Experiment 2 with the simultaneous choice between live prey of different size (1 white mouse vs. 1 white rat). We repeated each experiment six times across 6 weeks, testing half the cats first in Experiment 1 and then in Experiment 2, and the other half in the reverse order. In Experiment 1 the cats more often chose the larger number of small prey (3 mice), and in Experiment 2, more often the small size prey (a mouse). They also showed repeatable individual differences in the choices which they made and in the performance of associated predation-like behaviours. We conclude that domestic cats spontaneously discriminate between the number and size of potential prey in a way that can be interpreted as adaptive for a lone-hunting, obligate carnivore, and show complex levels of risk–reward analysis.
... Imagine a cheetah patiently scanning a herd of Thomson's gazelles to identify one to chase. The cheetah must first evaluate all its options before selecting one and initiating pursuit (Cooper et al., 2007). The cheetah is facing a control problem faced by many decision makers. ...
Economic choice proceeds from evaluation, in which we contemplate options, to selection, in which we weigh options and choose one. These stages must be differentiated so that decision makers do not proceed to selection before evaluation is complete. We examined responses of neurons in two core reward regions, orbitofrontal (OFC) and ventromedial prefrontal cortex (vmPFC), during two-option choice with asynchronous offer presentation. Our data suggest that neurons selective during the first (presumed evaluation) and second (presumed comparison and selection) offer epochs come from a single pool. Stage transition is accompanied by a shift toward orthogonality in the low-dimensional population response manifold. Nonetheless, the relative position of each option in driving responses in the population subspace is preserved. The orthogonalization we observe supports the hypothesis that the transition from evaluation to selection leads to reorganization of response subspace and suggests a mechanism by which value-related signals are prevented from prematurely driving choice.
... Certain factors may influence the behavior and prey selection of individual predators (Pettorelli et al. 2011) such as: if the predator is resident or transient (Chardonnet et al. 2010), body condition (Bauer and Iongh 2005;Chardonnet et al. 2010), the length of tenure in an area, learned behavior, or individual proclivities (Linnell et al. 1999;Chardonnet et al. 2010), gender and reproductive status Cooper, Pettorelli, and Durant 2007;Conde et al. 2010;Loarie, Tambling, and Asner 2013), etc. Time of day (or activity of livestock herd) ...
Large carnivores are a polarizing group of species that play an outsized role in relation to their number. They structure ecosystems and feature prominently in human culture. Yet, their place in a rapidly changing world is uncertain. The large carnivore guild in the five countries of East Africa, Burundi, Kenya, Rwanda, Tanzania, and Uganda, is largely intact; however, expanding human populations pose a substantial threat. Interventions are necessary to promote coexistence. To accomplish this, more accurate identification of threats, and improved understanding of species’ responses are needed. Primary threats to large carnivores in the region include habitat loss and human-wildlife conflict (HWC). Problematically, identification of human impacted areas from earth observation data can be difficult in heterogeneous savannah habitat, much of East Africa. I create a tool that enables land cover classification using Google Earth’s high-resolution imagery. With this tool I develop a data set of human impacted areas for East Africa. To ascertain carnivore response to human dominated lands, I use correlative species distribution modeling (SDM). Yet, there is no clear consensus on proper methods for generating pseudo-absence (PsA) data in these models. I review some existing methods in the context of their ecological meaning, and propose new PsA selection strategies. I then apply two novel and one existing PsA strategy to assess four carnivores’ (cheetah, wild dog, leopard, and lion) responses to human land cover and human population densities. Results suggest these carnivores are more susceptible to human land cover than human populations. Finally, I consider existing approaches of using SDM with HWC records to generate spatial risk maps with the goal of alleviating conflict. I draw on the SDM literature to highlight and demonstrate how two commonly overlooked issues in spatial risk modeling can hamper generating useful conclusions. In sum, these efforts represent attempts at improving commonly used methods used to study wildlife distribution and threats, and can be widely applied to other species and systems.
... Further research will be needed to test whether lynx actually adjust their hunting efforts in respect to the distribution of the bear feeding sites and local bear densities. Elsewhere, for example, it has been observed that cheetahs (Acinonyx jubatus) avoid hunting in areas with higher densities of lions, which regularly usurp cheetah kills (Cooper et al., 2007). ...
Interspecific interactions are one of the key factors in the evolution and ecology of animal communities. However, managers, conservationists and decision-makers rarely consider potential side-effects of bear management on other species. As the largest terrestrial scavengers with superb olfactory abilities, bears are one of the most important dominant scavengers and kleptoparasites in the Holarctic region. In this way several bear species frequently come in interactions with other predators and scavengers. Besides, bears perform several ecological roles ranging from seed dispersal to predation and directing nitrogen flow, thus affecting range of species from various guilds and ecosystems. At the same time, bears are usually actively managed through culling, reintroductions, translocations, and provision of anthropogenic food. Until recently, it was poorly understood how management of bears affect their interactions with other species and even more rarely were these aspects considered in the management decisions. An overview will be given on documented interspecific interactions involving bears and how various bear management measures could affect these interactions. As a study case, interactions between the brown bear and the Eurasian lynx in Slovenia will be presented, focusing on side-effects of intensive bear management on the endangered apex predator. Lynx are under strong pressure of kleptoparasitism by brown bears, resulting in a substantial loss of food for the lynx, which the predator is unable to compensate by increased hunting effort. This pressure is indirectly amplified by bear management measures, especially zone-specific culling and supplemental feeding of bears, which increased local bear densities and shortened bear denning period. Based on recent advances in the field, we call attention to the importance of considering interspecific interactions in bear-management decisions and generally in management of strongly-interacting species.
... The present study illustrated cheetah's predation in the presumed absence of large predators. However, cheetahs share most parts of their range with leopard and wolf in Iran, both of which can affect cheetahs' feeding ecology (Caro 1994, Cooper et al. 2007) and habitat selection (Mills et al. 2004, Pettorelli et al. 2008). This highlights the importance of conducting foraging ecological studies for managing predatorprey systems, especially when critically endangered carnivores are involved. ...
The Asiatic cheetah (Acinonyx jubatus venaticus), has disappeared in major parts of its mountainous habitats in west Asia. Asiatic cheetah is a critically endangered subspecies currently found only in central Iran. In this study, the feeding habits of Asiatic cheetah was investigated in two reserves in central Iran. Diet and prey selection of cheetah were assessed using two biomass models along with Jacob’s selectivity index. We found no significant difference between biomass consumption based on each model between the reserves or between models inside each reserve. Over 90 % of species diet was composed of three medium-sized ungulates (i.e. 15- 40 kg): wild sheep, wild goat and chinkara. Hares and other small mammals (less than 15 kg) made up the remainder of their diet. Asiatic cheetahs mainly preyed on wild sheep (Ovis vignei) which composed more than 50 % of consumed biomass. Wild sheep was identified as single staple prey, while chinkara (Gazella bennettii) was the most preferred prey despite its lower occurrence. Our study indicates that wild sheep, wild goat and especially chinkara are critical for persistence of Asiatic cheetah and must be particularly considered in conservation plans.
... The present study illustrated cheetah's predation in the presumed absence of large predators. However, cheetahs share most parts of their range with leopard and wolf in Iran, both of which can affect cheetahs' feeding ecology (Caro 1994, Cooper et al. 2007) and habitat selection (Mills et al. 2004, Pettorelli et al. 2008). This highlights the importance of conducting foraging ecological studies for managing predatorprey systems, especially when critically endangered carnivores are involved. ...
Abstract
The Asiatic cheetah (Acinonyx jubatus venaticus), has disappeared in major parts of its mountainous habitats in west Asia.Asiatic cheetah is a critically endangered subspecies currently found only in central Iran. In this study, the feeding habits of Asiatic cheetah was investigated in two reserves in central Iran. Diet and prey selection of cheetah were assessed using two biomass models along with Jacob’s selectivity index. We found no significant difference between biomass consumption based on each model between the reserves or between models inside each reserve. Over 90 % of species diet was composed of three medium-sized ungulates (i.e. 15- 40 kg): wild sheep, wild goat and chinkara. Hares and other small mammals (less than 15 kg) made up the remainder of their diet. Asiatic cheetahs mainly preyed on wild sheep (Ovis vignei) which composed more than 50 % of consumed biomass. Wild sheep was identified
as single staple prey, while chinkara (Gazella bennettii) was the most preferred prey despite its lower occurrence. Our study indicates that wild sheep, wild goat and especially chinkara are critical for persistence of Asiatic cheetah and must be particularly considered in conservation plans.
Key words: mammal, diet, selectivity, scat analysis, desert, carnivore
... Cheetahs actively move away from lion, leopard and spotted hyena (Durant, 2000b;Vanak et al. 2013). In addition, they maintain a minimum distance from lions which varies with vegetation type (Broekhuis et al., 2013;Vanak et al. 2013), and are less likely to go hunting when lions are in the vicinity (Cooper et al., 2007). In order to minimize encounters with larger carnivores at kill sites, cheetahs often move their kill to a safer area before feeding, they are vigilant (visually scanning the surrounding habitat) and leave their kill immediately after feeding (Hunter et al., 2007). ...
Zimbabwe used to hold the world third largest cheetah population. By 1999 the country’s cheetah population consisted of more than 1 500 cheetahs, the majority of which (80%) was found on commercial farmland. In those days, human-cheetah conflict was a main conservation threat. Since this last country wide assessment in 1999 there have been considerable changes in land use, which, in combination with poverty and an overall increase of the human population has had a serious impact on the cheetah population. Our survey shows the cheetah’s resident range has declined by 61%. The population has been reduced by at least 85% to 150-170 adult cheetahs, the majority of which reside in wildlife protected areas (80%). As a result, human-cheetah conflict is minimal and no longer regarded as a major conservation threat. With the current situation being the exact opposite of the historical situation there is a need to revise the cheetah management strategy in Zimbabwe by focusing conservation efforts on remaining viable free roaming cheetah populations and secure connectivity of these populations with larger transboundary populations.
... Generally the migration reaches the Northern Serengeti in July, and then spends August, September and October in the Maasai Mara before returning to Tanzania in November [27,28]. Independent of the migration, substantial populations of Thomson's gazellecheetahs preferred prey in East Africa [29]-are resident year round as are other prey species such as Grant's gazelle (G. granti), impala (Aepyceros melampus) and hares (Lepus spp.) [28,30]. ...
Many ecological theories and species conservation programmes rely on accurate estimates of population density. Accurate density estimation, especially for species facing rapid declines, requires the application of rigorous field and analytical methods. However, obtaining accurate density estimates of carnivores can be challenging as carnivores naturally exist at relatively low densities and are often elusive and wide-ranging. In this study, we employ an unstructured spatial sampling field design along with a Bayesian sex-specific spatially explicit capture-recapture (SECR) analysis, to provide the first rigorous population density estimates of cheetahs (Acinonyx jubatus) in the Maasai Mara, Kenya. We estimate adult cheetah density to be between 1.28 ± 0.315 and 1.34 ± 0.337 individuals/100km2 across four candidate models specified in our analysis. Our spatially explicit approach revealed ‘hotspots’ of cheetah density, highlighting that cheetah are distributed heterogeneously across the landscape. The SECR models incorporated a movement range parameter which indicated that male cheetah moved four times as much as females, possibly because female movement was restricted by their reproductive status and/or the spatial distribution of prey. We show that SECR can be used for spatially unstructured data to successfully characterise the spatial distribution of a low density species and also estimate population density when sample size is small. Our sampling and modelling framework will help determine spatial and temporal variation in cheetah densities, providing a foundation for their conservation and management. Based on our results we encourage other researchers to adopt a similar approach in estimating densities of individually recognisable species.
... In contrast, predation risk for Thomson's gazelles during the day is thought to be highest in the morning and late evening (Schaller 1972). Nevertheless, Cooper et al. (2007) reported that for the major day time hunter of Thomson's gazelles, the cheetah, the risk was not influenced by the time of day. However, in addition to the risk of predation, large mammals living in hot and arid environments face a risk of overheating and dehydration, and they have made several behavioral and physiological adaptations in order to conserve energy (Fuller et al. 2014). ...
Prey rely on making correct risk assessments when approached by potential predators in order to stay alive. We conducted experimental
human approaches with different simulated threat levels toward solitary adult male Thomson’s gazelles, that were located in
open grassland. We measured individuals flight initiation distance (FID), distance fled, escape speed, and the distance between
the location where the focal individual had stopped to flee and where the human stopped the approach (termed safety distance).
Multivariate analyses revealed an overall significant effect of starting distance, alertness, and time of day, but no statistical
effect was found for approach speed on the multivariate response. The individual responses showed a significant positive effect
of starting distance on both FID and safety distance. We also found a novel unimodal effect of time on FID. Finally, alertness
and approach speed only had a significant effect on safety distance, where faster approaches and individuals that displayed
alert behavior had shorter safety distances. Together, these findings indicate support for the “flush early and avoid the
rush” hypothesis, shows the necessity of using starting distance, alertness, and time as covariates when testing the effects
of threat level, and demonstrate the usefulness of the new metric safety distance.
... Further research will be needed to test whether lynx actually adjust their hunting efforts in respect to the distribution of the bear feeding sites and local bear densities. Elsewhere, for example, it has been observed that cheetahs (Acinonyx jubatus) avoid hunting in areas with higher densities of lions, which regularly usurp cheetah kills (Cooper et al., 2007). ...
... Further research will be needed to test whether lynx actually adjust their hunting efforts in respect to the distribution of the bear feeding sites and local bear densities. Elsewhere, for example, it has been observed that cheetahs (Acinonyx jubatus) avoid hunting in areas with higher densities of lions, which regularly usurp cheetah kills (Cooper et al., 2007). ...
Scavenging is an important ecosystem process, and often a factor influencing the prey utilization success of large predators. We studied scavenger activity on prey remains of Eurasian lynx (Lynx lynx) in Northern Dinaric Mountains using video surveillance and survey of kill sites. Prolonged time of consumption, usually lasting several days, makes Eurasian lynx very vulnerable to kleptoparasitism. We recorded 16 vertebrate and several invertebrate scavengers feeding on 68 lynx prey remains. The most common visitor of lynx kills was red fox (Vulpes vulpes). However, we observed that brown bears (Ursus arctos) have the largest impact on lynx’ prey utilization success, as they usually consume the entire carcass whenever they find it. Scavenging by bears considerably decreases prey utilization success of lynx and we estimated the overall loss due to bear kleptoparasitism at approximately 12 %. Besides the prey loss caused by animals, some prey is also lost to humans that remove it from the forest. Although kleptoparasitism is probably not the major reason for the recent decline of the Dinaric lynx population, it affects the lynx’ prey utilization and might become an important factor if combined with a depleted prey base due to inappropriate management.
... In feeding strategies of fish, mouth size and gape size limit feeding on prey larger than the fish's own mouth (Renones et al. 2002;Arim et al. 2007). To match increased energy requirements, a quantitative or qualitative change in diet is expected (Cooper et al. 2007). Olson and Boggs (1986) mentioned that the daily ration of Yellowfin Tuna is 3.9-6.7% of their body mass and their energy requirement is a function of swimming speed. ...
The Yellowfin Tuna Thunnus albacares is one of the major fish species caught around subsurface fish aggregation devices (FADs) in the waters southwest of Taiwan. However, how it interacts with other organisms around FADs is poorly known. In this study, the diet and feeding habits of juvenile Yellowfin Tuna were estimated from the analysis of stomach contents from 1,477 specimens with FLs ranging from 24 to 108 cm and stable isotope analysis (202 specimens) collected around FADs in the waters southwest of Taiwan. The analysis of stomach contents indicated that juvenile Yellowfin Tuna with FL < 50 cm mainly feed on larval purpleback flying squid Sthenoteuthis oualaniensis , larval shrimps, and zooplanktonic organisms such as amphipods. Yellowfin Tuna with FL of ∼50 cm switch their diet to teleost fishes such as Japanese Barracudina Lestrolepis japonica , Skinnycheek Lanternfish Benthosema pterotum , and fishes in the families Exocoetidae and Scombridae. Stable isotope analysis indicated that the δ ¹⁵ N values ranged between 6.2‰ and 12.6‰, and the estimated trophic position varied from 3.18 ± 0.24 for tuna with FL < 30 cm, while it reached 4.59 ± 0.50 for those with FL > 50 cm and 4.75 ± 0.06 for those with FL > 90 cm. Based on the distinct diet shift of the juvenile Yellowfin Tuna, demonstrated by both stomach contents and stable isotope analyses, this study concluded that the tuna shift their diet at approximately 50 cm FL.
Received March 31, 2015; accepted September 9, 2015
... In the context of the First Commandment -Sharing in Scarcity -the author observed fodder and water sharing practices among wildebeest during the peak of dry season as shown in Great Serengeti. This is consistent with behaviours that Cooper et al. (2007) observed among many predators in the Serengeti who share a kill regardless of its size. Group sharing of a kill or water points at the peak of dry season are common characteristics among preys and predators. ...
The enormous pressure on the Earth system and gross inequity in sharing resources require human centred remedial actions. This study explores potentials of human behavioural change in addressing
prevailing global ecological crises and resource governance challenges. The study assumes that
humans can learn some basic principles from wildlife experiences to fix sustainability uncertainties.
Thus, the author observed wildlife behavioural patterns in the Serengeti ecosystem in East Africa
from 17 documentary films produced between 1959 and 2014. Animal behavioural ecology theories,
biomimicry, documentary film analysis, and computer-aided simulation guided the study design.
Observations focussed on behaviours that influenced wildlife sustainable resource use particularly in
times of abundance, scarcity and climatic uncertainty. The identified wildlife behavioural patterns
were codified into Ten Commandments that can serve as moral compass for guiding human survival
in the Anthropocene. The Ten Commandments identified are connected to human dimensions of
sustainability and principally the role of individual and group behaviour in fostering social-ethical
environmental governance. The findings of this study implied that humans can survive the
Anthropocene and its uncertainties by mimicking the robust, resilient, and behaviour-driven benign
and often altruistic resource use dynamics exhibited by wildlife in Serengeti. Finally, the NetLogo
simulation of climate and resource availability scenarios revealed a rather strong linear relation
between climatic stability and future resource sustainability in the Serengeti ecosystem.
Keywords: Access and allocation; behaviour; human dimensions; sustainability; transformation
... Henschel & Ray, 2003). In this study, cheetah was seen to be primarily nocturnal, although usually described as diurnal (Cooper, Pettorelli & Durant, 2007), such a difference in behaviour could be a tactic to avoid persecution. ...
Interspecific competition often occurs when sympatric carnivores compete for the same, limited resources, although the degree of competition between species pairs may vary with biotic factors such as body size, diet and population density. Avoidance of dominant competitors along the axes of space and time is a potential mechanism for reducing chances of direct encounters between species. However, when resources are essential and spatially fixed, options for spatial partitioning may be limited. We examined resource partitioning within a guild of eight carnivore species at water sources across two commercial farmlands in southwest Namibia. In this semi-desert environment, surface water is scarce and farmers are forced to provision water for livestock through artificial means. Camera traps were used to record spatial and temporal activity patterns of carnivore species at artificial and natural permanent water sources. We found that carnivores use either spatial or temporal resource partitioning, with temporal partitioning being most frequently seen. An association was seen between difference in body mass and degree of spatial partitioning, where species pairings with larger differences in body mass showed the greatest degree of partitioning. These results show that while in arid environments water is rare and used by a number of carnivore species, resource partitioning allows a guild of carnivores, including species of conservation concern, to coexist outside of protected areas.
... They were satisfied with whatever small meal they had eaten. Cooper (2007) observed that hunting decisions were independent of the cheetahs hunger level, at times even with high abundance of specific prey, they chose not to hunt, possibly due to preferring smaller, less vigilant herds, or to avoid predation or kleptoparisitism that can accompany larger herds, even with no competitor present. The cheetahs hunting decisions may be affected by this genetically built in anti-predator behaviour (Hobson et al., 1988;McLean, 1996). ...
... Therefore, increased consumption of fish by females could be due to an energy demand for the reproductive processes such as gonadal development, egg formation and gestation (King & Murphy, 1985). A qualitative or quantitative shift in their diets for meeting these growing requirements could be expected (Cooper et al., 2007). Finally, several factors might influence the feeding of A. doellojuradoi. ...
The feeding ecology of the southern thorny skate, Amblyraja doellojuradoi, on the Argentine Continental Shelf was evaluated using generalized linear models. Amblyraja doellojuradoi preyed mainly on crabs (85.41% index of relative importance (IRI)) and to a lesser extent on polychaetes (4.98% IRI), teleosts (3.28% IRI), isopods (2.03% IRI), other crustaceans (1.52% IRI) and other invertebrates (2.78% IRI). As individuals increased in size, the consumption of crabs also increased and the consumption of polychaetes and other invertebrates decreased. The study area was divided into a northern (36°–43°S) and a southern (43°–50°S) region. Regarding the latitude of capture, it was observed that A. doellojuradoi mainly fed on crabs in the north and on fish, isopods and other crustaceans in the south. Females of A. doellojuradoi had a stronger preference for fish and isopods than males. As to sexual maturity, immatures fed more on polychaetes and other crustaceans than did mature. The ontogenetic change in feeding habits could be attributed to body size and an increasing ability to capture larger prey, rather than to food availability. However, this point cannot be confirmed because little is known about the benthic fauna of this area.
... Predation by large carnivores can potentially exert a strong top-down control on the demography of wild ungulates (Festa-Bianchet et al., 2006;Nilsen et al., 2009a). However, the strength of top-down control varies, and understanding inter-and intraspecific patterns of prey selection shown by predators is thus important (Cooper, Pettorelli & Durant, 2007;Gervasi et al., 2012). ...
Predator selectivity for age and sex classes has large implications for their impact on prey populations. We examined whether the Eurasian lynx Lynx lynx selects specific sex and age categories of roe deer Capreolus capreolus, and if this selection pattern differs between summer and winter. Data on sex and age of 194 roe deer killed by 44 VHF-and GPS-marked lynx were collected in southern Norway from 1995 to 2010. The sex and age distribution of the roe deer population was esti-mated using demographic parameters estimated from radio-collared roe deer in the study area. We found that lynx selection differed between summer and winter. In both seasons, lynx selected adult roe deer of both sexes. In summer, there was a clear selection against yearlings, but in winter, lynx selected male yearlings. Compared with the availability, fawns of both sexes were under-represented during summer. Male and female lynx did not differ in their prey selection, but yearling lynx tended to kill a larger proportion of roe deer fawns than older lynx. We argue that seasonal differences in behaviour, activity and habitat use by roe deer may explain this variation in lynx selection patterns, supporting the view that prey selection is affected by the life cycle stage of both the predators and the prey.
Livestock guardian dogs (LGDs) are increasingly used to protect livestock from predators, but their effects on the distribution and behaviour of wild predators are mostly unknown. A key question is whether LGDs exclude predators from grazing land, or if predators continue to use areas with LGDs but modify their behaviour in ways that reduce impacts on livestock.
We studied effects of LGDs (Maremma sheepdogs) on distribution and behaviour of red foxes Vulpes vulpes in north‐eastern Victoria, Australia. We mapped the activity of LGDs across the study areas using GPS tracking and measured fox activity using remote cameras. We also measured risk‐sensitive foraging in foxes to test if they reduced feeding time at sites regularly used by LGDs.
Foxes occurred throughout areas occupied by LGDs, but their probability of detection was negatively related to the probability of LGD presence. Foxes extracted fewer food items from experimental food stations in proportion to the intensity of local activity of LGDs. This indicates that, though foxes overlapped with LGDs, they responded to risk of encountering LGDs by allocating less time to foraging.
While LGDs do not necessarily exclude wild predators from areas used for livestock production, they can have strong effects on predator behaviour. Reduction in time allocated to foraging in areas regularly used by LGDs could lead to suppression of hunting behaviour and therefore a reduction in attacks on livestock. The flexible response of predators to LGDs should facilitate coexistence of wild predators with livestock farming, by allowing predators to continue to use areas occupied by livestock while still preventing attacks on those livestock. Our results therefore strengthen the case for use of LGDs in the conservation of predators threatened by conflict with farming. Suppression of hunting behaviour should also mean that prey species experience reduced rates of predation on farmland with LGDs. This effect could be valuable for conservation of threatened species of prey.
Stable isotope palaeoecology of fossil mammals is a key research tool for understanding the environmental context of hominin evolution in the Plio-Pleistocene of Africa. Well studied mammal groups include bovids, suids, equids, proboscideans and primates, but to date there has been no in-depth study of modern and fossil carnivores. Here we produce an Africa-wide oxygen and carbon enamel isotope dataset for modern carnivores and compare it with fossil carnivore data sampled from the Plio-Pleistocene Omo Group of the Turkana Basin, Kenya. Comparison of modern carnivore carbon isotopes with satellite images of land cover indicates that carnivore δ¹³C is related to the proportion of woody cover in the local environment. Modern carnivore oxygen isotopes are strongly influenced by the δ¹⁸O of meteoric water, through drinking from standing water and through prey body fluids. Carbon isotope data from fossil carnivores shows close agreement with palaeovegetation reconstructions from δ¹³C of palaeosol carbonates from the same geological Members, and a similar long-term trend in δ¹³C values through time (4 Ma to 1 Ma), reflecting a gradual increase in the proportion of C4 grasses in the Turkana Basin. This increase in the δ¹³C of large carnivores is consistent with the evidence from other mammalian groups for an increase in the proportion of grazers compared to browsers and mixed feeders during this time interval. Two distinct trends within oxygen versus carbon isotope space indicates that the fossil carnivores lived during two distinct climatic regimes – one in which palaeo-lake Turkana was freshwater, and one in which the lake resembled its modern-day hyperalkaline state. These two climatic states most likely represent the end-members of precessionally-driven rainfall extremes over the Ethiopian Highlands. This indicates that each studied faunal assemblage from the Omo Group is a time- and climate-averaged palimpsest; this has significant implications for the interpretation of environmental signals and community palaeoecology derived from Turkana Basin fossil mammals, including early hominins.
Animals must eat other organisms to obtain nutrients. The varied ways in which they do this, combined with the fact that the other organisms usually resist this process, means that the study of foraging is fascinatingly complex. The study of foraging includes dietary choice and specific feeding adaptations as some nutrients are essential for life and others may be difficult to digest. The plants and animals in which these nutrients reside are usually well-defended or difficult to find or catch. Because of this, foraging ranges from grazing and browsing to cooperative hunting of large prey to imbibing the blood of other animals. Parasitism is a specialized form of foraging in which the predator lives on or within its host. Parasites often manipulate the behavior of their hosts in order to facilitate transmission to the next host. Optimal foraging theory helps us to understand how foraging animals make decisions about what to eat and where to eat it.
Conflicts between large mammalian predators and humans present a challenge to conservation efforts, as these events drive human attitudes and policies concerning predator species. Unfortunately, generalities portrayed in many empirical carnivore landscape selection studies do not provide an explanation for a predator's occasional use of residential development preceding a carnivore–human conflict event. In some cases, predators may perceive residential development as a risk–reward trade‐off.
We examine whether state‐dependent mortality risk‐sensitive foraging can explain an apex carnivore's ( Puma concolor ) occasional utilization of residential areas. We assess whether puma balance the risk and rewards in a system characterized by a gradient of housing densities ranging from wildland to suburban. Puma GPS location data, characterized as hunting and feeding locations, were used to assess landscape variables governing hunting success and hunting site selection. Hunting site selection behaviour was then analysed conditional on indicators of hunger state.
Residential development provided a high energetic reward to puma based on increases in prey availability and hunting success rates associated with increased housing density. Despite a higher energetic reward, hunting site selection analysis indicated that pumas generally avoided residential development, a landscape type attributed with higher puma mortality risk. However, when a puma experienced periods of extended hunger, risk avoidance behaviour towards housing waned.
This study demonstrates that an apex carnivore faces a trade‐off between acquiring energetic rewards and avoiding risks associated with human housing. Periods of hunger can help explain an apex predator's occasional use of developed landscapes and thus the rare conflicts in the wildland–urban interface. Apex carnivore movement behaviours in relation to human conflicts are best understood as a three‐player community‐level interaction incorporating wild prey distribution.
Little is currently known in regard to the specific nutritional requirements of cheetahs (Acinonyx jubatus). Similarities and differences with the domestic cat (Felis catus), lion (Panthera leo), and wolf (Canis lupus) are explored to infer information on the captive cheetah. Knowledge of the cheetah's free-ranging dietary intake is considered as a potential proxy for determining species-specific nutritional requirements. The current understanding of the role that diet and nutrition play in captive cheetah health is highlighted, with discussion of lifestage-specific feeding, nutritional disorders, diet-related diseases, and the nutritional adaptations toward obligate carnivory. Challenges for future research include the elucidation of the nutrient intake of wild cheetahs [as opposed to the dietary (i.e., prey) intake], and identification of nutritional drivers of gastrointestinal disease in captive cheetahs. In particular, further determination of the role that dietary fiber plays in cheetah health is deemed a priority.
Ontogenetic niche shifts in diet are a consequence of changes in body size or resource partitioning between age classes. To better resolve the feeding patterns of the Japanese scallop Mizuhopecten yessoensis, we examined the relative importance of age and size in the diet of this species using stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) from 2006 to 2009. Contribution of food sources was quantified using an isotope mixing model by comparing the muscle tissue isotope ratios to those of suspended particulate organic matter (SPOM) and their zooplankton prey (e.g. micro- and meso-zooplankton). Unlike the δ13C values, which remained constant with age and size, muscle δ15N values were more positively correlated with age accounting for 69 % of variations than size with only 46 %. Increasing 15N values with age suggested that shifts in diet from SPOM to micro- and meso-zooplankton occurred during ontogeny in M. yessoensis. Results of the isotope mixing model indicated that SPOM contribution to scallop’s diet decreased from 68 to 8 % while those of zooplankton increased from 15 to 50 % with increasing age. This study concludes that age-related dietary shift explains the enrichment of 15N, as a result of predation on zooplankton by M. yessoensis.
Predator–prey interactions are central to our understanding of adaptive evolution and community ecology. A growing body of research indicates that predation risk and prey selection can be highly variable from one individual to another; nonetheless, individual variability both within predators and within prey is still classically ignored when attempting to model predator–prey dynamics. This chapter explores how our current knowledge of the factors shaping prey selection and predation risk relate to current modelling approaches of predator–prey dynamics. It also discusses how dismissal of inherent individual heterogeneity in predator–prey interactions may be impacting our ability to advance food web theory as well as our understanding of evolutionary trajectories in predator and prey populations. It finally reviews possible methodological frameworks that could help integrate individual variability into the modelling of predator–prey interactions.
Predation has long been implicated as a major selective force in the evolution of several morphological and behavioral characteristics of animals. The importance of predation during evolutionary time is clear, but growing evidence suggests that animals also have the ability to assess and behaviorally influence their risk of being preyed upon in ecological time (i.e., during their lifetime). We develop an abstraction of the predation process in which several components of predation risk are identified. A review of the literature indicates that an animal's ability to assess and behaviorally control one or more of these components strongly influences decision making in feeding animals, as well as in animals deciding when and how to escape predators, when and how to be social, or even, for fishes, when and how to breathe air. This review also reveals that such decision making reflects apparent trade-offs between the risk of predation and the benefits to be gained from engaging in a given activity. Despite this body of evidence, several areas in the study of animal behavior have received little or no attention from a predation perspective. We identify several such areas, the most important of which is that dealing with animal reproduction. Much work also remains regarding the precise nature of the risk of predation and how it is actually perceived by animals, and the extent to which they can behaviorally control their risk of predation. Mathematical models will likely play a major role in future work, and we suggest that modelers strive to consider the potential complexity in behavioral responses to predation risk. Overall, since virtually every animal is potential prey for others, research that seriously considers the influence of predation risk will provide significant insight into the nature of animal behavior.
The literature on cheetah Acinonyx jubatus ecology is dominated by studies on the Serengeti Plains (SNP) in East Africa. Because of this and the cheetah's hunting strategy it is generally considered to be a predator that prefers open grassland plains. However, cheetahs also inhabit a range of bush, scrub and woodland habitats. A field study using direct observations of radio-collared individuals in the woodland savanna habitat of the Kruger National Park (KNP), South Africa, and a literature review of studies across savanna habitats examined cheetah predation, hunting behaviour and habitat use in relation to prey composition, cover availability and kleptoparasitism. The cheetah's main prey is medium-sized herbivores, with a bias towards male prey. The group size and sex of the hunting cheetah may influence the results of prey selection studies as male coalitions tend to take larger prey than females. Cheetahs initiated more hunts and had a higher success rate in the open woodland savanna of the KNP compared to other available habitats with thicker bush, and in other wooded savanna areas they also prefer more open habitat for hunting. Although they appear to have shorter chase distances in more wooded habitats, hunting success appears to be slightly higher in open grassland habitat. Woody vegetation appears to obstruct the cheetah's high-speed hunting strategy, thereby lowering hunting success. However, cheetahs use cover for stalking prey and open habitats with bordering woodlands, or patches of cover are considered preferred cheetah habitats. In these habitats, cheetahs can stalk closer to their prey using available cover, but also successfully pursue their prey into available open spaces. Across African savanna ecosystems, cheetahs appear to be kleptoparasitised less in more wooded habitats. Therefore they may also prefer these habitats because they provide greater concealment from kleptoparasites. Our study suggests that the cheetah is more adaptable to habitat variability than is often thought and is not only a successful hunter on open grassland plains.
Examined the ecological interactions among four species of co-occurring predators, adult brook trout Salvelinus fontinalis (98-122 mm standard length), larval Gyrinophilus porphyriticus (36-58 mm snout-vent length), larval Eurycea bislineata (13-21 mm SVL), and Cambarus bartonii (6-17 mm carapace length) in an experiment that began in mid-June and ran for 3 mo. Brook trout affected both survival and growth of the larger salamander species, Gyrinophilus, and Salvelinus and Gyrinophilus affected the growth of the smaller salamander Eurycea and the crayfish Cambarus. Presence of Gyrinophilus had no effect on relative condition or fecundity of Salvelinus. Large predators caused Cambarus and Eurycea to alter their activity levels and habitat, but Gyrinophilus made no adjustments to the presence of Salvelinus. Gyrinophilus is vulnerable to predation/aggression from brook trout, but Eurycea and Cambarus can behaviorally avoid predation by both large predators at a significant cost to growth. Interactions among predators in headwater streams directly and indirectly influence population dyanmics of the interacting species by affecting survival, growth, behavior, and habitat use. -from Author
Food consumption, food preferences and transit time of digesta were determined in captive giant otters, Pteronura brasiliensis, at the National Institute of Amazon Research (INPA), Manaus, Brazil. Food consumption of an adult female was 0.0997 kg 1 day 1. Giant otters showed significant and varied preferences for the single Siluriformes (catfish) and various Characiformes species offered. The adult female preferred Anostomidae and Hypophthalmus (catfish), followed by Triportheus. Myleinae (pacu) were the least preferred, and other species of Characiformes offered were intermediate between Triportheus and Myleinae but not different from one another. The subadult male preferred Psectrogaster, Potamorhina and Semaprochilodus, followed by Hypophthalmus and finally Hemiodontidae. Within species, larger fish are chosen significantly more often than smaller fish (78.7% of trials, P=0.002). Species, size and individual otter significantly affected the percentage of times fish offered were consumed completely (P<0.016). Overall, most fish were consumed completely beginning with the anterior end. Characoids were consumed completely more often than sil-uroids (77.8% vs. 38.6% of trials, P<0.0001), but the percentage of times different characoids were consumed completely varied (range 0–100%). Small fish (5–15 cm) are more likely to be consumed completely than medium (15–25 cm) fish (84.9% vs. 80.2% of trials, P<0.02). Transit time of particulate markers averaged 3.13 h. Captive preferences are compared to diets of wild otters in the region (central Amazônia), and implications of study results for determination of food habits in wild otters using scat analysis are discussed.
Predation has long been implicated as a major selective force in the evolution of several morphological and behavioral characteristics of animals. The importance of predation during evolutionary time is clear, but growing evidence suggests that animals also have the ability to assess and behaviorally influence their risk of being preyed upon in ecological time (i.e., during their lifetime). We develop an abstraction of the predation process in which several components of predation risk are identified. A review of the literature indicates that an animal's ability to assess and behaviorally control one or more of these components strongly influences decision making in feeding animals, as well as in animals deciding when and how to escape predators, when and how to be social, or even, for fishes, when and how to breathe air. This review also reveals that such decision making reflects apparent trade-offs between the risk of predation and the benefits to be gained from engaging in a given activity. Despite this body of evidence, several areas in the study of animal behavior have received little or no attention from a predation perspective. We identify several such areas, the most important of which is that dealing with animal reproduction. Much work also remains regarding the precise nature of the risk of predation and how it is actually perceived by animals, and the extent to which they can behaviorally control their risk of predation. Mathematical models will likely play a major role in future work, and we suggest that modelers strive to consider the potential complexity in behavioral responses to predation risk. Overall, since virtually every animal is potential prey for others, research that seriously considers the influence of predation risk will provide significant insight into the nature of animal behavior.
The prey preferences of African lions (Panthera leo) in Serengeti National Park, Tanzania, were examined in three ways. First, lion encounter rates with prey types were measured
and compared with a random sample of the prey population. Lions encountered more wart hogs (Phacochoerus aethiopicus), Grant's gazelles (Gazella granti), wildebeests (ConnochaeUs taurinus), and zebras (Equus burchelli) than expected. Second, preferred prey types of lions were identified using conditional logit analysis. Lions preferred to
hunt small prey groups, groups that were closer than 200 m, and groups that contained wart hogs, wildebeests, or zebras. Third,
a risk-minimization optimal foraging model and a rate-maximization model were used to predict lion preferences. The foraging
theory models predict that preferences should change with season and with lion group size. Qualitative support was found for
most of these predictions.
Small bluegills Lepomis macrochirus shift their habitat use in the presence of their predator, largemouth bass Micropterus salmoides. The addition of bass causes small bluegills to make greater use of structured (vegetated) habitats and reduces their use of open (limnetic) habitats. By stocking small bluegills with and without bass, pronounced differences in zooplankton abundance and size structure developed between treatments, with 3 cladocerans (Daphnia, Diaphanosoma, Ceriodaphnia), and the phantom midge Chaoborus, becoming more abundant with bass. These effects of bass were not due to changes in bluegill abundance, as very few bluegills were eaten by the bass, and bluegill densities did not differ between treatments. Bluegills exerted substantial mortality on the zooplankton and cladocerans experienced lower per capita death rates (due to bluegill) in the presence of bass. Results are discussed in light of theory predicting how foragers should deplete prey among habitats that differ in mortality risk. -from Authors
Food consumption, food preferences and transit time of digesta were determined in captive giant otters, Pteronura brasiliensis, at the National Institute of Amazon Research (INPA), Manaus, Brazil. Food consumption of an adult female was 0.0997 kg1 day1. Giant otters showed sig- nificant and varied preferences for the single Siluriformes (catfish) and various Characiformes species offered. The adult female preferred Anostomidae and Hypophthalmus (catfish), fol- lowed by Triportheus. Myleinae (pacu) were the least preferred, and other species of Characiformes offered were intermediate between Triportheus and Myleinae but not different from one another. The subadult male preferred Psectrogaster, Potamorhina and Semaprochilodus, followed by Hypophthalmus and finally Hemiodontidae. Within species, larger fish are chosen significantly more often than smaller fish (78.7% of trials, P=0.002). Species, size and individual otter significantly affected the percentage of times fish offered were consumed completely (P
Cheetah Acinonyx
jubatus home-range size and habitat use were analysed using radio-tracking data collected in the southern district of the Kruger National Park (KNP) between 1987 and 1990. Meaningful estimates of home-range size, using the 95% minimum convex polygon method, were 126 km2 for a three-male cheetah coalition, 195 km2 for a solitary male, and 150 km2 and 171 km2 for two female cheetahs. Although cheetahs used all habitats according to their availability, they did show a preference for open savanna habitat because their core or total home ranges centred on these habitats. Female cheetahs used denser woodland habitat more frequently than males, as they seemed to be influenced by the distribution of their main prey, impala Aepyceros
melampus, which also preferred denser woodland habitat.
Food habits of tigers Panthera tigris in terms of prey abundance were studied in the semi-arid deciduous forests of Ranthambhore National Park, western India, between November 2000 and April 2001. Wild prey availability was assessed by line transects (n=8) and prey selection by the tigers was determined from analysis of scats (n=109). Compared to some other parts of the country, prey abundance was found to be high at 96.65 animals km−2. Chital Axis axis was the most abundant wild prey in the study area, followed by common langur Presbytis entellus, sambar Cervus unicolor, nilgai Boselaphus tragocamelus, wild pig Sus scrofa and chinkara Gazella bennetti. Chital (c. 31%) and sambar (c. 47%) constituted the bulk of the tigers' diet and were preferred prey. Nilgai and chinkara contributed minimally to the tigers' diet (c. 5–7% and <1%, respectively) and were used less than their availability. Domestic livestock made up 10–12% of the tigers' diet. The average weight of an animal consumed was between 107 and 114 kg reflecting a preference for large prey. The analysis reveals that parts of Ranthambhore have high prey abundance, thus making it important for long-term tiger conservation. Despite the high prey abundance, tigers were still considerably dependent on domestic livestock, posing challenges for the park management to resolve potential areas of conflict.
We compare the dynamics of predator-prey systems with specialist predators or adaptive generalist predators that base diet choice on energy-maximizing criteria. Adaptive predator behaviour leads to functional responses that are influenced by the relative abundance of alternate prey. This results in the per capita predation risk being positively density-dependent near points of diet expansion. For a small set of parameter values, systems with adaptive predators can be locally stable whereas systems with specialist predators would be unstable. This occurs mainly when alternate prey have low enough profitability that predators cannot sustain themselves indefinitely when feeding on alternate prey. Local stability of systems with adaptive predator behaviour is inversely related to the goodness of fit to optimal diet choice criteria. Hence, typical patterns of partial prey preference are more stabilizing than perfect optimal diet selection. Locally stable systems with adaptive predators are often globally unstable, converging on limit cycles for many initial population densities. The small range of parameter combinations and initial population densities leading to stable equilibria suggest that adaptive diet selection is unlikely to be a ubiquitous stabilizing factor in trophic interactions.
Prey selection and feeding habits of lions Panthera leo, spotted hyaenas Crocuta crocuta, cheetahs Acinonyx jubatus and leopards Panthera pardus are investigated. Lions kill mainly adult gemsbok Oryx gazella and blue wildebeest Connochaetes taurinus, tending to select older animals of both species and males in the case of gemsbok. Spotted hyaenas also prey mainly on gemsbok and wildebeest, but select for juveniles, particularly from gemsbok. Cheetahs prey heavily on springbok Antidorcas marsupialis lambs and then on adult males and older individuals. Leopards also prey relatively heavily on springbok, but appear to have a wider diet than cheetahs do. It is concluded that predators generally have a small impact on their prey populations in the southern Kalahari, although in the case of springbok they do appear to influence the structure of the population.
A particular linear programming model is constructed to predict the diets of each of 14 species of generalist herbivores at the National Bison Range, Montana. The herbivores have body masses ranging over seven orders of magnitude and belonging to two major taxa: insects and mammals. The linear programming model has three feeding constraints: digestive capacity, feeding time and energy requirements. A foraging strategy that maximizes daily energy intake agrees very well with the observed diets. Body size appears to be an underlying determinant of the foraging parameters leading to diet selection. Species that possess digestive capacity and feeding time constraints which approach each other in magnitude have the most generalized diets. The degree that the linear programming models change their diet predictions with a given percent change in parameter values (sensitivity) may reflect the observed ability of the species to vary their diets. In particular, the species which show the most diet variability are those whose diets tend to be balanced between monocots and dicots. The community-ecological parameters of herbivore body-size ranges and species number can possibly be related to foraging behavior. Peer Reviewed http://deepblue.lib.umich.edu/bitstream/2027.42/47765/1/442_2004_Article_BF00377109.pdf
This paper introduces new forms, sampling and estimation approaches fordiscrete choice models. The new models include behavioral specifications oflatent class choice models, multinomial probit, hybrid logit, andnon-parametric methods. Recent contributions also include new specializedchoice based sample designs that permit greater efficiency in datacollection. Finally, the paper describes recent developments in the use ofsimulation methods for model estimation. These developments are designed toallow the applications of discrete choice models to a wider variety ofdiscrete choice problems. Peer Reviewed http://deepblue.lib.umich.edu/bitstream/2027.42/47225/1/11002_2004_Article_138116.pdf
Prey selection and feeding habits of lions Panthera leo, spotted hyaenas Crocuta crocuta, cheetahs Acinonyx jubatus and leopards Panthera pardus are investigated. Lions kill mainly adult gemsbok Oryx gazella and blue wildebeest Connochaetes taurinus, tending to select older animals of both species and males in the case of gemsbok. Spotted hyaenas also prey mainly on gemsbok and wildebeest, but select for juveniles, particularly from gemsbok. Cheetahs prey heavily on springbok Antidorcas marsupialis lambs and then on adult males and older individuals. Leopards also prey relatively heavily on springbok, but appear to have a wider diet than cheetahs do. It is concluded that predators generally have a small impact on their prey populations in the southern Kalahari, although in the case of springbok they do appear to influence the structure of the population.
AlSTCT.--Based upon previous reports of high visual acuity in falcons, we hypothesized that prey activity influenced prey selection by American kestrels (Falco sparverius) more than prey size. Wild, free- ranging kestrels were simultaneously offered one adult (22-30 g, 3.5-4.0 cm in length) and one juvenile (6-12 g, 2.0-2.5 cm in length) brown laboratory mouse (Mus musculus). Mice were presented to kestrels on a 1 x 1 m board with a light-green background marked into 10 x 10 cm squares. To prevent escape, each mouse was tethered to a clear strand of monofilament fishing line. Mouse activity was documented by observing the mice through 8 x binoculars and recording the behavior of each mouse into a portable cassette recorder. In trials pairing active mice (large or small) with inactive (dead) mice (large or small), kestrels selected active mice 90% of the time. Kestrels also selected the more active of two mice significantly (regardless of size) in trials which we reduced the activity of one mouse, or in trials which one mouse was naturally less active than the other. These results suggest that within the range of prey sizes used in this study, kestrels select prey on the basis of activity, and exhibit little size discrimination in prey choice decisions.
1. Ecological factors influencing prey selection by tiger Panthera tigris, leopard Panthera pardus and dhole Cuon alpinus were investigated in an intact assemblage of large mammals in the tropical forests of Nagarahole, southern India, between 1986 and 1990. 2. Densities of large herbivores were estimated using line transects, and population structures from area counts. Carnivore diets were determined from analyses of scats (faeces) and kills. Selectivity for prey species was inferred from likelihood ratio tests comparing observed counts of scats to hypothesized scat frequencies generated from prey density estimates using parametric bootstrap simulations. Predator selectivity for size, age, sex and physical condition of prey was estimated using selection indices. 3. Ungulate and primate prey attained a density of 91 animals km-2 and comprised 89-98% of the biomass killed. Predators showed significant (P
The bluegill sunfish, Lepomis macrochirus, is known to select prey on the basis of size. We present evidence that this size selection is related to the optimal allocation of time spent searching for, and handling prey. A model relating search and handling time to energy return is constructed to determine the optimal breadth of diet. Prey are permitted to differ in size and relative abundance. All elements of the model are estimated from experiments with the bluegill feeding on populations constructed from size classes of Daphnia magna. Relative visibility of the different prey sizes markedly affects relative encounter rates or @'effective@' proportions. Effective proportions are determined empirically from feeding experiments and theoretically from reaction distance in order to correct for this bias. Search time is then manipulated by varying absolute abundance of prey. At low absolute abundance, prey of different size are eaten as encountered. As prey abundance is increased, size classes are dropped sequentially from the diet in accordance with the theory. Search and handling times are estimated from these experiments and quantitative comparisons with the model indicate these changes in diet maximize return with respect to time spent foraging.
In various settings the authors show how behavior can be a response to heterogeneity, introducing nonlinear density dependence and qualitatively altering population dynamics. Also, even simple behaviors can cause nonadditivity, which is an interaction between environmental and density-dependent processes. It has a critical effect on the coexistence of competing species. To understand these various joint effects of behavior and heterogeneity on population dynamics, the general effects of behavior on dynamics are discussed. The authors then consider examples of the various ways in which heterogeneity affects dynamics, and for each example consider the interaction of behavior with heterogeneity. -from Authors
This is an account of the life and habits of two species of Hyaena, the brown and the spotted, living in South Africa. It contains a considerable body of detailed knowledge, including painstaking nightwork, and it provides help in designing management strategies for species in need of protection. --- Part 1 Feeding ecology: food availability; brown hyaena diet; spotted hyaena diet; diets of the other large carnivores and ecological separation of the predators; the impact of predation on the prey populations; relations between hyaenas and other carnivorous animals. Part 2 Comparative foraging and feeding behaviour: activity patterns and resting sites; foraging group sizes; the use of senses during foraging; foraging for vegetable matter, birds' eggs and insects; brown hyaena hunting behaviour; spooted hyaena hunting behaviour; feeding behaviour. Part 3 Social structure and spatial organization: brown hyaena clans; spotted hyaena clans; nomadic males; land tenure system; factors affecting the sizes of social groups and territories. Part 4 Communication patterns and social interactions: visual and tactile communications and social interactions; vocalizations; scent marking. Part 5 The comparative denning behaviour and development of cubs: dens; development of cubs; sub-adults; functional considerations of denning behaviour in the Hyaenidae. Part 6 The individual in hyaena society: degrees of relatedness between clan members; brown hyaena society; spotted hyaena society; evolutionary trands in the social systems of the two species. Part 7 Relations between, and management considerations for, brown hyaenas and spotted hyaenas. Appendices: 1 - common and scientific names of species mentioned in the text; 2 - estimated numbers of some ungulates in the spotted hyaena study area; 3 - ageing criteria of ungulates based on eruption of teeth in bottom jaws and tooth wear; 4 - methods used to measure territory sizes; 5 - degrees of relatedness between clan members.
African wild dogs ( Lycaon pictus) are a seriously endangered species with only around 5000 individuals left. We examined the factors likely to be affecting the distribution and density of wild dogs living in the Kruger National Park, South Africa. We collected data, by traditional and satellite radio‐tracking, on diet selection, sizes of packs, dispersion and sizes of territories, and patterns of habitat selection for eight packs of wild dogs. In Kruger wild dogs specialize on impala ( Aepyceros melampus) and kudu ( Tragelaphus strepsiceros). They live in packs averaging about nine dogs and inhabit territories of 350–950 km ² . Neighboring territories overlap to some extent but packs meet very rarely. The dispersion pattern of food plays only a minor role in determining the density and distribution of dogs in the Kruger; dogs exist at their lowest density where their food is most abundant. This apparent paradox comes about because the dogs seem to avoid areas that, although prey‐rich, are heavily used by lions. This is a sensible strategy because lions are a major cause of dog mortality, accounting for some 39% of natural pup deaths and at least 43% of natural adult deaths. Wild dogs may be conserved most successfully in areas with moderate to low densities of lions and spotted hyenas, and management strategies should be careful not to promote these species to the detriment of wild dogs and other carnivores. The densities of lions and spotted hyenas should be important criteria when considering an area for the reintroduction of wild dogs and other similar sized carnivores.
Factores que Afectan la Densidad y Distribución de Perros Salvajes en el Parque Nacional Kruger
El perro salvaje africano ( Lycaon pictus) es una especie en serio peligro de extinción, con una población estimada de solamente 5000 individuos. Hemos examinado los factores que con mayor probabilidad afectan la distribución y densidad de los perros salvajes que habitan el Parque Nacional Kruger en Sudáfrica. Información sobre la selección de alimento, tamaño de grupo, dispersión y tamaño de territorio y patrones de selección de hábitat fué colectada usando métodos tradicionales y seguimiento con satélite para ocho grupos de perros salvajes en el parque. Esta especie se especializa en impala ( Aepyceros melampus) y kudu ( Tragelaphus strepsiceros). Vive en grupos de 9 individuos en promedio y habita un territorio de 350‐950 km ² . Territorios vecinos se sobreponen en cierta proporción, pero los encuentros entre diferentes grupos raras veces ocurren. El patrón de dispersión de la comida juega solo un pequeño papel en la determinación de la densidad en lugares donde la comida es mas abundante. Esta aparente paradoja es consecuencia de que los perros parecen evitar zonas que, a pesar de ser ricas en presas, también son muy usadas por leones (Panthera leo). Esta estrategia es sensata, pues esta especie es una de las mayores causas de mortalidad para los perros, alcanzando un 39% de mortalidad natural de los cachorros y al menos un 43% de la mortalidad natural de los adultos. Los perros salvajes podrían ser conservados con mas éxito en zonas con una densidad moderada o baja de leones y hienas manchadas (Crocuta crocuta). Las estrategias de conservación deben ser cuidadosamente estudiadas para evitar favorecer estas especies en detrimento de los perros salvajes y otras especies de carnívoros. La denisdad de leones y hienas manchadas deberá ser un criterio importante cuando se considere una zona para la reintroducción de los perros salvajes y otros carnívoros de similar tamaño.
The success of a pack of African wild dogs, Lycaon pictus, hunting Thomson's gazelles, Gazella thomsoni, and blue wildebeest, Connochaetes taurinus, in Serengeti National Park, Tanzania, was influenced by the age of the prey and the number of dogs hunting together, but not by the amount of cover available, the size of prey groups, or the distance at which prey groups fled. The study suggested two ways in which wild dogs may benefit from communal hunting. First, it increased the range of prey species available to the pack. Although single dogs regularly killed both immature and adult Thomson's gazelles, they were not observed to kill wildebeest calves, and groups of two did not hunt adult wildebeest successfully. Larger groups were more successful than smaller ones. Second, hunting in groups reduced interspecific competition from spotted hyaenas, Crocuta crocuta , through improved defence of carcasses.
The technique of iterative weighted linear regression can be used to obtain maximum likelihood estimates of the parameters with observations distributed according to some exponential family and systematic effects that can be made linear by a suitable transformation. A generalization of the analysis of variance is given for these models using log-likelihoods. These generalized linear models are illustrated by examples relating to four distributions; the Normal, Binomial (probit analysis, etc.), Poisson (contingency tables) and gamma (variance components). The implications of the approach in designing statistics courses are discussed.
This study was an investigation of the diet and of prey selection by a population of African wild dogs Lycaon
pictus in the Savé Valley Conservancy (SVC) in the south-east lowveld of Zimbabwe. The diet of the dogs, based on the number of kills for each species located, consisted almost entirely of impala Aepyceras
melampus (74%) and kudu Tragelaphus
strepsiceros (22%), the two most abundant medium-sized antelope in the area. The level of selection for different prey classes killed by the wild dogs was investigated and it was found that the wild dogs: (1) exhibited strong selection for a number of prey classes on a seasonal basis; (2) selected kudu throughout the year but showed little selection between the other prey species; (3) selected the young of both impala and kudu and selected males at times of the rut. Bone marrow analysis showed that prey killed by the wild dogs on SVC were in poorer condition than unselectively culled individuals suggesting the selection of the weaker individuals in the prey populations.
The condition and age of Thomson's gazelles (Gazella thomsoni) killed by two species of predators were compared. The wild dog, a coursing predator, was predicted to take a greater proportion of young, old and sick animals than the cheetah, a stalker. As measured by the marrow fat content of limb bones, wild dogs captured more Thomson's gazelles in poor condition than cheetahs. This appeared to be a consequence of their preference for male gazelles, which were in worse condition than females. Cheetahs did not capture fewer young and old gazelles than wild dogs.
The small population of wild dog Lycaon pictus (n= 3 to 30) in Hluhluwe-Umfolozi Park (HUP) has declined since 1992. The survival of dogs in HUP is dependent on the reintroduction of more dogs; however, wild dog reintroduction programmes are fraught with problems and many have failed. In this paper the diet and capture success of the wild dog pack in the Hluhluwe Section, and the influence of dietary considerations on the success of the future reintroduction of wild dogs in this reserve, are investigated. Diet choice was determined from scat analysis, personal observation and field staff records. Eight ungulate prey species were identified from scat analysis: nyala Tragelaphus angasi and impala Aepyceros melampus were the most abundant ungulate species in HUP and accounted for 77% of the diet. On the whole, wild dogs included prey types in the diet consistent with a rate-maximizing foraging approach, although some prey were clearly taken opportunistically. The dogs preyed mostly on small- (> 25 kg) to medium-sized (40–90 kg) prey, while the young of large (< 90 kg) prey species or scavenged carcasses supplemented the diet during the dry season. Adult nyala were taken more frequently than other age classes, but wild dog preyed on juvenile impala more than expected. Female prey were taken more frequently than males but selection did not differ from prey population sex ratios. Prey capture success was similar to that of previous studies from both open and densely wooded habitats and the wild dogs successfully caught 48% of all prey species pursued. Results suggest that wild dogs are quite capable of adapting both their diet choice and foraging technique to the dense vegetation in HUP. We conclude that prey type, prey availability and habitat constraints on prey capture success, will not affect the reintroduction of more wild dogs into HUP.
Increased energetic expenditure during lactation must be met either from metabolic stores or by increasing food intake. Additional behavioural costs and constraints may be imposed on those species that conceal their young in a fixed place. This study examines how wild cheetahs, Acinonyx jubatus, alter their behaviour during lactation and whether denning involved extra costs or constraints. Females almost doubled their food intake when lactating, although only mothers with cubs in the lair increased the time they spent drinking. Higher levels of food intake were achieved by catching a greater proportion of larger prey items, hunting these at a higher rate and by increasing the success rate of hunts. Lactating females with emerged cubs increased the proportion of time they spent observing and hunting relative to time spent resting and moving. When lactating females had cubs in the lair they were on the move for longer each day, travelled further, had restricted ranging patterns and tended to make more kills in the heat of the day than when accompanied by their cubs. These latter results suggest that the need to find a safe place, near water, in which to conceal immobile and vulnerable cubs may impose additional behavioural constraints and costs and lactating females.
1. In the last two decades predator–prey models have shown that ‘refuges’, in which prey can seek respite from predation, are crucial for the persistence of prey and predator. This concept is equally applicable to interspecific competition and, in a heterogeneous environment, species with low competitive ability should seek out ‘competition refuges’ where competition is reduced.
2. Cheetahs have low competitive ability compared with their principal competitors, hyenas and lions, which are directly responsible for their low density. This study uses distribution data collected in the Serengeti National Park in Tanzania over a 4-year period to show that cheetahs are more strongly associated with each other than with their competitors and utilize areas with low-density prey.
3. Cheetahs exhibit local avoidance behaviour in both space and time with respect to lions and hyenas. This behaviour is facultative and is strongest when cheetahs are engaged in activities that might expose them to food loss or increase the risk of close interactions, such as when they are hunting or eating.
4. Lactating cheetahs, whose range is restricted, are more likely to have difficulties finding prey and come into more frequent contact with lions than free-ranging animals.
5. It is argued that although cheetahs always lose in direct competition, they persist in the ecosystem by seeking out ‘competition refuges’ with low densities of lions and hyenas and that their mobility is the key to their continued coexistence with these predators. This pattern of distribution may be generally applicable to other species which, although widely distributed, always occur at low densities.
Food habits of tigers Panthera tigris and population attributes of prey species (population structure, density and biomass) were studied in the tropical dry deciduous forest of Pench National Park, Central India, from November 1998 to April 1999. Scat analysis and line transect method were used to estimate tiger food habits and density of major prey species, respectively. The 61.1 km2 intensive study area was found to have very high ungulate density (90.3 animals km−2) with chital Axis axis being the most common species (80.7 animals km−2), followed by sambar Cervus unicolor (6.1 animals km−2). Common langur Presbytis entellus was the most abundant (77.2 animals km−2) primate species. When the density figures were multiplied by the average weight of each prey species, a high biomass density of 6013.25 kg km−2 was obtained for the intensive study area. Chital (47.3%) along with sambar (14.5%) and wild pig Sus scrofa (10.9%) constituted the major part of the tiger's diet. If there is food choice, tigers seem to kill medium- and large-sized species more often. Wild pig and sambar were consumed more than their availability, whereas chital were taken in proportion to their availability. Gaur Bos gaurus and nilgai Bosephalus tragocamelus were not represented in the tiger's diet. Common langur was consumed in lesser proportion by tigers than expected by estimates of its density. The average weight of animals consumed by tigers in the intensive study area was 82.1 kg. The analyses revealed that Pench harbours very high prey density and tigers are mostly dependent on the wild ungulates rather than on domestic livestock as is the case in many other areas in the Indian subcontinent. These two factors thus make Pench National Park a potential area for long-term conservation of tigers.
Juvenile mortality in cheetahs was found to be extremely high compared to other large mammals, with approximately 72.2% of litters dying before they emerged from the lair at eight weeks of age. An average of 83.3% of cubs alive at emergence died by adolescence at 14 months of age, thus cheetah cubs were estimated to have only a 4.8% chance of reaching independence at birth. The instantaneous rate of mortality was highest immediately after cubs emerged from the lair. Before emergence, lion predation was the major source of this mortality, although some cubs died from starvation after they were abandoned by their mothers, or as a result of grass fires and inclement weather. After emergence, predation again accounted for virtually all cub mortality, with lions and spotted hyaenas taking approximately the same proportion of cubs. Overall predation accounted for 73.2% of cheetah cub deaths in this study, with 78.2% of these being killed by lions. The extent of maternal care, in the form of vigilance and antipredator behaviour, mirrored cub susceptibility to mortality and, in the case of vigilance, possibly also starvation. The probability of a cheetah mother responding aggressively to a predator was found also to depend on the species of predator. This study highlights the importance of the influence of juvenile mortality on patterns of parental care.
A long‐term (13‐year) data set, based on > 4000 kills, was used to test whether a sympatric group of large predators adheres to the theoretical predictions that (1) mean prey body size and (2) prey diversity increase as functions of predator body size.
All kills observed by safari guides are documented routinely in Mala Mala Private Game Reserve, South Africa. We analysed these records for lion ( Panthera leo , Linnaeus), leopard ( Panthera pardus , Linnaeus), cheetah ( Acinonyx jubatus , Schreber) and African wild dog ( Lycaon pictus , Temminck). Males and females of the sexually dimorphic felid species were treated as functionally distinct predator types. Prey types were classified by species, sex and age class.
Prey profiles were compared among predator types in terms of richness and evenness to consider how both the range of prey types used and the dominance of particular prey types within each range may be influenced by predator size. No significant size‐dependent relationships were found, so factors separate from or additional to body size must explain variation in prey diversity across sympatric predators.
A statistically strong relationship was found between mean prey mass and predator mass ( r ² = 0·86, P = 0·002), although pairwise comparisons showed that most predators killed similar prey despite wide differences in predator size. Also, minimum prey mass was independent of predator mass while maximum prey mass was strongly dependent on predator mass ( r ² = 0·71, P = 0·017). The ecological significance is that larger predators do not specialize on larger prey, but exploit a wider range of prey sizes.
A major objective in behavioural and evolutionary ecology is to understand how animals make decisions in complex environments. Examinations of animal behaviour typically use optimization models to predict the choices animals ought to make. The performance of animals under specific conditions is then compared against the predicted optimal strategy. This optimization approach has come into question because model predictions often do not match animal behaviour exactly. This has led to serious scepticism about the ability of animals to exhibit optimal behaviour in complex environments. We show that conventional approaches that compare observed animal behaviour with single optimal values may bias the way we view real-world variation in animal performance. Considerable insight into the abilities of animals to make optimal decisions can be gained by interpreting why variability in performance exists. We introduce a new theoretical framework, called multi-objective optimization, which allows us to examine decision-making in complex environments and interpret the meaning of variability in animal performance. A multi-objective approach defines the set of efficient choices animals may make in attempting to reach compromises among multiple conflicting demands. In a multi-objective framework, we may see variation in animal choices, but, unlike single-objective optimizations where there is one best solution, this variation may represent a range of adaptive compromises to conflicting objectives. An important feature of this approach is that, within the set of efficient alternatives, no choice can be considered to yield higher fitness, a priori, than any other choice. Thus, variability and optimal behaviour may be entirely consistent. We illustrate our point using selected examples from foraging theory where there is already an optimization program in place.
Cheetahs, Acinonyx jubatus, in the Serengeti National Park kill more male Thomson's gazelles, Gazella thomsoni, than expected from the sex ratio of the local population. This paper examines whether behavioural differences between male and female gazelles predispose males to higher rates of predation. Cheetahs hunting groups of Thomson's gazelles preferentially selected individuals that were positioned on the periphery of groups, were further from their nearest neighbours, were in areas of high vegetation, were less vigilant and were either in small groups or on their own. As a result, male Thomson's gazelles, which tended to concentrate on the periphery of groups, had greater nearest-neighbour distances, were less vigilant and were found in smaller groups, were more vulnerable than females and were preferentially selected from groups. There was no evidence that males were more vulnerable because they tended to concentrate in areas of high vegetation. Overall, gazelles in groups were far less vulnerable to predation than solitary individuals and the fact that males spent so much more time alone than females was another factor contributing to their high risk of predation; although solitary males were actually better at escaping once chased by cheetahs than solitary females, the difference in escape ability was not sufficient to offset the high number of attacks experienced by males as a result of their more solitary behaviour.
Kingdon's remarkable seven-volume masterwork on East African mammals concludes with two volumes on the bovids, placing them in a broad comparative, ecological, and evolutionary context. Volume IIIC covers cattle, water buffalo, kudus, elands, dwarf antelopes, duikers, reedbucks, and waterbucks; IIID covers gazelles, impalas, wildebeests, oryxes, sheep, and goats. In addition to the stunning, lifelike drawings that are an integral part of the text, the volumes include a reappraisal of bovid taxonomy and original analyses of the form and function of body shape and size, horn shape, coat pattern, and tooth structure.
Cheetahs of the Serengeti Plains is the most comprehensive account of carnivore social behavior to date. Synthesizing more than a decade of research in the wild, this book offers a detailed account of the behavior and ecology of cheetahs. Compared with other large cats, and other mammals, cheetahs have an unusual breeding system; whereas lions live in prides and tigers are solitary, some cheetahs live in groups while others live by themselves. Tim Caro explores group and solitary living among cheetahs and discovers that the causes of social behavior vary dramatically, even within a single species. Why do cheetah cubs stay with their mother for a full year after weaning? Why do adolescents remain in groups? Why do adult males live in permanent associations with each other? Why do adult females live alone? Through observations on the costs and benefits of group living, Caro offers new insight into the complex behavior of this extraordinary species. For example, contrary to common belief about cooperative hunting in large carnivores, he shows that neither adolescents nor adult males benefit from hunting in groups. With many surprising findings, and through comparisons with other cat species, Caro enriches our understanding of the evolution of social behavior and offers new perspectives on conservation efforts to save this charismatic and endangered carnivore.
Thesis (Ph. D.)--University of Cambridge, 1988.