Article

Why leopards commit infanticide

October 2013
Animal Behaviour 86(4):791-799

DOI:10.1016/j.anbehav.2013.07.019

Authors:

Guy Balme

Panthera

Luke T. B. Hunter

Wildlife Conservation Society

Infanticide is a widespread but seldom observed behaviour that has been shown to convey strong selection forces on some social mammals. However, infanticide in nonsocial species is less clearly understood, particularly the evolutionary function of infanticide. Here we present direct and indirect evidence of infanticide in a large, solitary felid, the African leopard, Panthera pardus, and determine its likely causes in light of six explanatory hypotheses. Observed and inferred rates of infanticide for leopards were among the highest recorded for mammalian carnivores, accounting for almost half of juvenile mortality and nearly a third of all offspring. Our results demonstrate that infanticide in leopards is mainly an adaptive behaviour which provides reproductive benefits to perpetrators. Infanticidal males were typically unrelated to their victims, the death of unweaned offspring shortened the interbirth intervals of mothers, and perpetrators increased their chances of mating with and siring the mother's subsequent litter. Female leopards also appear to have developed a profusion of strategies to counter the risk of infanticide, providing further support for the sexual selection hypothesis. Cannibalism may provide some incentive for infanticide (perpetrators usually consumed their victims) but this is probably an added, minor benefit rather than the primary driver for the behaviour. Our findings suggest that infanticide is a key factor shaping the sociospatial ecology of leopards. They also highlight the importance of accounting for functional components of population dynamics when managing large carnivores, particularly for invasive activities that artificially elevate adult male turnover.

INCIDENCE OF INFANTICIDE AMONG CAPTIVE WILDLIFE IN SOME SELECTED ZOOS IN NIGERIA

Article

Full-text available

Jul 2022

This study aimed at revealing the cause of infanticide among zoo collections and proffer strategies to mitigate its occurrence. Three zoos in Nigeria were studied using empirical data from 20-year Veterinary retrospective records and circumstances surrounding the occurrence. A total of 17 infanticide cases were reported from three zoos in Nigeria; 8 from UNILORIN Zoo, seven from UI Zoo and two from Kano Zoo. A total of 55 infants were found to have died during the 17 infanticide events. The Nile Crocodile accounted for the highest number of individual infant deaths, while the side-striped jackal accounted for the highest frequency of infanticide events. The occurrence was highest in carnivores, and major offenders were of maternal origins, accounting for 59% of all infanticides. Exploitation was observed as the major motive, either sole or combined with other motives. This study assessed scenarios surrounding maternal infanticide in different animal species and predisposing factors peri-occurrence. We also proposed possible solutions, especially in developing nations' zoo settings, where this occurrence is grossly under-reported and most often neglected. Correction of observed factors linked with infanticide led to the prevention of further occurrence of infanticide in the three zoos.

Factors predicting habitat use by leopards in human-altered landscapes

Article

Oct 2021

Transformed landscapes caused by human activity leave remnant patches of natural habitat for wildlife. The persistence of species in the face of such transformation depends on individuals’ ability to adapt to novel habitat, and to secure resources and reproductive opportunities despite habitat alterations. The leopard, Panthera pardus, is the last free-roaming top carnivore in South Africa whose high trophic status and wide-ranging movements make them an effective focal species in conservation planning. Using location data from leopards, we investigated key correlates of habitat selection in human-altered landscapes at two spatial scales. We compared sex-related differences and predicted how conspecific home range locations influenced habitat selection. Leopards avoided human-altered landscapes more strongly at the large spatial scale, where both sexes selected core areas near formally protected areas. Conspecific home range locations had a strong positive effect at both spatial scales for males, while for females, conspecifics explained fine-scale habitat selection by selecting areas near neighboring females. Spatial scale, sex-related differences, and conspecific location play roles in habitat selection for solitary felids and have implications for conservation planning and management. Excluding these factors may result in inappropriate species management policies.

Factors predicting habitat use by leopards in human-altered landscapes

Article

Oct 2021

Sex-specific seasonal variation in puma and snow leopard home range utilization

Article

Full-text available

Aug 2018

Territory size is often larger for males than for females in species without biparental care. For large solitary carnivores, this is explained by males encompassing a set of female territories to monopolize their reproduction during mating (area maximization). However, males are expected to behave more like females outside of breeding, with their area utilization being dependent on the range required to secure food resources (area minimization). To examine how male and female solitary carnivores adjust their spatial organization during the year as key resources (mates and prey) change, we radio-collared 17 pumas (Puma concolor; nine males and eight females) and 14 snow leopards (Panthera uncia; seven males and seven females) and estimated home range size and overlap on two temporal scales (annual vs. monthly). Contrary to expectation, we found no evidence that males monopolized females (the mean territory overlap between females and the focal male during the mating season was 0.28 and 0.64 in pumas and snow leopards , respectively). Although male-male overlap of annual home ranges was comparatively high (snow leopards [0.21] vs. pumas [0.11]), monthly home range overlaps were small (snow leopards [0.02] vs. pumas [0.08]) suggesting strong territoriality. In pumas, both males and females reduced their monthly home ranges in winter, and at the same time, prey distribution was clumped and mating activity increased. In snow leopards, females showed little variation in seasonal home range size, following the seasonal stability in their primary prey. However, male snow leopards reduced their monthly home range utilization in the mating season. In line with other studies, our results suggest that female seasonal home range variation is largely explained by changes in food resource distribution. However, contrary to expectations, male territories did not generally encompass those of females, and males reduced their home ranges during mating. Our results show that male and female territorial boundaries tend to intersect in these species, and hint at the operation of female choice and male mate guarding within these mating systems.

Infanticide in a jaguar (Panthera onca) population—does the provision of livestock carcasses increase the risk?

Article

Full-text available

Oct 2016

Infanticide is an antagonistic behavior that may provide an evolutionary benefit for the perpetrator. Cases of infanticide have rarely been reported in Neotropical carnivores. The objective of this study was to provide empirical evidence of infanticide in a local jaguar (Panthera onca) population in the Brazilian Pantanal. We present infanticide data from opportunistic sampling. Each month, from 2013 to 2015, we monitored pastures for evidence of livestock carcasses. A remotely triggered camera trap was placed at encountered fresh cattle carcasses. Through this monitoring, two cases of infanticide were recorded. Both cases occurred in close proximity to a cattle carcass, a large prey item that may attract multiple jaguars—including females with cubs around age of weaning—and increase the risk of infanticide. Our observations provide new empirical evidence of jaguar social behavior and intraspecific competitive interactions, potentially driven by locally high population density and resource provision.

Report of conspecific pup consumption by the crab‐eating fox Cerdocyon thous (Carnivora, Canidae)

Article

Jun 2023

In the Canidae family, cases of infanticide have been recorded in populations of dingoes, wolves and red foxes. The consumption of individuals from the same species has not been recorded yet for the crab‐eating fox ( Cerdocyon thous ), a medium‐sized South American canid with generalist eating habits; however, in a semi‐arid region in north‐eastern Brazil, two C. thous faecal samples were found in August and October 2018 with fur and fragments of paws from young individuals of this species. Cases of offspring consumption have also been reported in other carnivore species from semi‐arid regions, and it is a phenomenon that might be related to the scarcity of resources and a mechanism for obtaining food. Competition for resources is also hypothesized to explain these natural events in nature, as the death of a pup results in greater access to resources for the parent and its offspring. Thus, infanticide can increase the chances of survival of the mother or the other pups.

Unveiling demographic and mating strategies of Panthera onca in the Pantanal, Brazil

Article

Full-text available

Jan 2023

We conducted the first long-term and large-scale study of demographic characteristics and reproductive behavior in a wild jaguar (Panthera onca) population. Data were collected through a combination of direct observations and camera trapping on a study area that operates both as a cattle ranch and ecotourism destination. Jaguars exhibited two birth peaks: April/May and October/November, that are the end and the beginning of the wet season in the Pantanal, respectively. The average litter size was 1.43 ± 0.65. Single cubs made up a total of 65.7% of the births, and we found a slight predominance of females (1.15:1 ratio) in litters. The mean age at independence was 17.6 ± 0.98 months, with sex-biased dispersal, with all males (n = 27) leaving the natal home range and 63.6% of females exhibiting philopatry. The interbirth intervals were 21.8 ± 3.2 months and the mean age at first parturition was 31.8 ± 4.2 months. Our results estimated a lifetime reproductive success for female jaguars of 8.13 cubs. Our observations also indicate that female jaguars can display mating behavior during cub rearing or pregnancy, representing 41.4% of the consorts and copulations recorded. We speculate that this behavior has evolved as a defense against infanticide and physical harm to the female. To our knowledge, this is the first time that such behavior is described for this species. All aggressive interactions between females involved the presence of cubs, following the offspring–defense hypothesis, that lead to territoriality among females in mammals, regardless of food availability. In the face of growing threats to this apex predator, this work unveils several aspects of its natural history, representing a baseline for comparison with future research and providing critical information for population viability analysis and conservation planning in the long term.

Like mother like daughter: quantifying the relationship between relatedness and phenotypic similarity in leopard pelage patterns

Article

Oct 2022

Leopard, Panthera pardus, populations have been substantially affected by range contractions and fragmentation. Declining populations with less connectivity have a higher probability of reduced genetic diversity which may ultimately impact resilience to novel threats. Monitoring genetic diversity is thus an important component of the conservation of threatened species. In many species, genetic similarity has been shown to correlate with phenotypic resemblance raising the question of whether photographs can be used to infer pedigree relatedness. In this study we use a long-term leopard monitoring database comprising photographs and life history records from the last 20 years that represent a population of wild leopards in South Africa with known identities and maternal relationships. We generated phenotypic similarity scores for all combinations of leopard individuals in the population using ImageJ and HotSpotter software, and manually scored the number and position of leopard whisker spots. We then estimated mother–offspring similarity using regression analysis for each phenotypic trait quantified. Of the 15 traits measured, six showed significant mother–offspring relationships. However, the relationship between phenotype and pedigree relatedness weakened across individuals with decreasing levels of relatedness. Therefore, while some pelage patterning traits are heritable in leopards, the relationship is not consistently strong enough to predict genetic relatedness, and thus genetic diversity, within leopard populations. In light of our findings we provide a useful benchmark of phenotypic variation present within a healthy, stable leopard population.

Patterns of Diurnal and Nocturnal Cub-Directed Social Interaction and Guarding Behaviour in Sumatran Tigers

Article

Sep 2022

Felids are commonly housed in zoological collections worldwide. While aspects of their behaviour are well studied, there remain questions on best practice husbandry including during reproduction and breeding scenarios. In 2016, the Zoological Society of London’s (ZSL) London Zoo held a pair of Sumatran tigers (Panthera tigris sumatrae) for the purpose of breeding. While they are believed to be solitary in the wild, many collections maintain their tigers in pairs, with some keeping pairs together during parturition and rearing periods. The aim of this study was to investigate the social interactions between a male Sumatran tiger and cubs when housed in a shared enclosure. The data were collected using CCTV footage in the indoor enclosure for the tigers. The CCTV footage ran continuously throughout the day and night, allowing a more holistic overview of behaviour. These 24-hour recordings were split into 6 equal hour ranges to calculate behaviour activity budgets and proximity of the male from the cubs. Data were analysed using a Chi-squared test for association to determine differences between individual behaviour. Overall, the male spent longer than expected engaging in guarding behaviour of the cubs. The male also regularly engaged in affiliative behaviours directed towards the cubs. No cub-directed aggression was observed from the male toward the cubs. Overall, this suggests that maintaining a male tiger with its progeny may be feasible as a management approach in some zoological collections, provided the male’s personality is compatible, and alternative accommodation is available. Keywords: Felidae; Affiliative Behaviour; Guarding; Nocturnal Behaviour; Zoo; Panthera Tigris Sumatrae

CONSERVATION OF LEOPARDS (PANTHERA PARDUS) IN THE EASTERN AND WESTERN CAPE, SOUTH AFRICA: INVESTIGATING THE EFFECT OF LAND USE, GENE FLOW AND CONNECTIVITY

Thesis

Dec 2017

Jeannine McManus

The increasing extent of human-altered landscapes and associated human activities is projected to cause irreparable damage to biodiversity and ecosystem function by the end of the century. The conservation of species requires understanding the abilities and limitations of species persistence in modified landscapes and how this affects species population dynamics and connectivity between populations. The persistence of species in the face of altered habitat depends, in part, on the capacity of habitat patches to promote occupancy, and the ability of individuals to reach these patches and ensure fitness within them by balancing resources and threats despite the altered nature of the habitat. The distribution of animal populations across the landscape is the result of decisions individuals make in selecting and avoiding environmental characteristics over time. Carnivores interact strongly with other species and thereby have the ability to structure communities and ecosystems, often making them a focal species for conservation planning. Leopards (Panthera pardus) are the last free-roaming large carnivores in South Africa and, while they are considered highly adaptable to environmental changes, most leopard habitat exists outside protected areas, where they are increasingly threatened by habitat fragmentation and human-caused mortality. Their important ecological role and vulnerability to humans have raised concerns regarding the likelihood of carnivores to survive in human-altered landscapes. This thesis examines the behaviour of leopards in their environment, and how these behaviours influence leopard distribution, population structure and connectivity. This study found that conspecifics, sex-related differences and anthropogenic landscape features effect how leopards distribute themselves in the landscape, influence movement patterns, and shape their population structure. Sexes employed different strategies in selecting habitat and movement patterns, likely because of different reproductive- and conspecific avoidance strategies. Often habitat prediction modelling for solitary carnivores does not incorporate sex, and conspecifics’ locations and this research found these variables are important in leopard habitat selection and movement patterns. Male and female leopards, respectively, spent 70% iv and 40% of the time moving in long, straight movement patterns (inter patch behaviour). Inter patch behaviour is indicative of low resource areas, fragmented habitat, or areas with higher intraspecific avoidance and is employed to move quickly between habitat patches. Connectivity between habitat patches was reduced by human-associated features such as roads, and promoted by mountainous areas, rivers and protected areas, the latter being less affected by human-associated features. Despite the high occupancy of inter patch behaviour displayed by males, the leopard population in the region are genetically sub-structured into three subpopulations. While this population broadly conforms to a metapopulation model, gene flow between the three identified sub-populations shows low to moderate gene flow and requires management to ensure continued connectivity between these populations. These findings can contribute to improving leopard management policy at a landscape level to ensure this flagship species survives in heterogeneous environments.

Using reintroduction to elucidate breeding system, breeding phenology and infanticide for a solitary carnivore

Article

Mar 2020

Breeding systems affect the timing of reproduction, spacing patterns and social organization, individual fitnesses, and population sizes. For many species, information on breeding systems and mating is limited or untested in wild populations, resulting in management actions that are incompletely informed. We used photographic data collected on a reintroduced fisher (Pekania pennanti (Erxleben, 1777)) population in northern California to test hypotheses about the breeding system, the timing of breeding, and the potential for male infanticide. We documented fishers of both sexes breeding with multiple partners in the same year, demonstrating polygynandry. We use logistic and linear regression to evaluate the timing and frequency of male visitation at 262 reproductive dens used by 50 individual females. Of 46 documented copulations and 577 male visits, 100% and 95% occurred while females had kits in their natal dens. Seventy five percent of documented male visits occurred before 31 March and 95% of occurred before 17 April. Observed breeding occurred within a mean of 3.1 (± 1.6) days of locating females’ natal dens. We found no evidence for male directed infanticide. Our results add precision to the timing of the reproductive cycle and provide the first descriptions of male-female interactions for wild fishers.

The evolution of male infanticide in relation to sexual selection in mammalian carnivores

Article

Full-text available

Feb 2018
EVOL ECOL

The evolution of infanticide by males has often been explained by the sexual selection hypothesis, which posits that infanticide improves male reproductive success by shortening the interbirth intervals of the mothers of the killed offspring. In Carnivora, however, the fitness advantages assumed in this hypothesis have been shown in only a few species, and it has been argued that male infanticide may be nonadaptive in pinniped carnivores. According to the sexual selection hypothesis, male infanticide is expected to be more prevalent in species in which males are subjected to stronger sexual selection through intrasexual competition over mates. We examined a phylogenetically corrected relationship between male infanticide and sexual size dimorphism (SSD) as a measure of the intensity of sexual selection in carnivores. Our analyses failed to detect a significant association between the occurrence of male infanticide and SSD across carnivores, although they showed that, among fissipeds (typically terrestrial carnivores), males in species with stronger male-biased SSD are significantly more likely to commit infanticide. This suggests that the evolution of male infanticide is correlated with intense sexual selection in fissipeds. In pinnipeds (Odobenidae, Otariidae, and Phocidae), there was no significant association between male infanticide and SSD. Assuming that SSD represents the intensity of sexual selection on males, this result is consistent with the argument that infanticide by male pinnipeds is not a sexually selected behaviour.

Home ranges, activity patterns and habitat preferences of leopards in Luambe National Park and adjacent Game Management Area in the Luangwa Valley, Zambia

Article

Nov 2017

Leopard (Panthera pardus) populations are declining worldwide. There are limited data on leopard ecology, especially activity patterns and habitat use, but these are vital to facilitate their conservation. In Zambia we radio tracked two female and three male leopards to study home range sizes, activity patterns and habitat preferences in Luambe National Park (LNP), and an adjacent Game Management Area used for trophy hunting. Home range sizes (MCP 95%) comprised 28.3–55.7 km² for males and 3.1–42,3 km² for females; Kernel densities (50%; 95%) were 32.5 − 80.6 km² for males and 3.0–23,0 km² for females. The home range for one female shrank during motherhood. Analysis of habitat use and activity patterns of leopards revealed sex-specific differences. Males showed a higher mobility than females. During 24-hour observations all individuals showed a minimum mobility during noon hours and maximum mobility before sunrise and sunset. Analyses of habitat preferences using the Jacob-Index and R package adehabitatHS showed that leopards prefer denser vegetation types and rather avoid grassland. These findings should be taken into account in conservation decisions, for example in the granting of trophy hunting activities.

Home ranges, activity patterns and habitat preferences of leopards in Luambe National Park and adjacent hunting area in the Luangwa Valley, Zambia

Article

Aug 2016

Social organization of a solitary carnivore, the leopard, inferred from behavioural interactions at marking sites

Article

Apr 2023
ANIM BEHAV

Intraspecific interactions shape animal social networks and regulate population dynamics. Species with solitary life histories rely on communication cues for population regulation, especially olfaction for many terrestrial mammals. Increasing evidence shows complex social structures among presumably solitary species and although social factors may play a key role in spatial organization, we lack insights into how species with solitary life histories structure and maintain sociospatial systems. Herein, we applied a social network approach to decode leopard, Panthera pardus, behaviour and interactions at marking sites that we monitored with camera traps. We found that leopard social units within our study area consisted of up to five individuals and that same-sex and opposite-sex interactions were equally likely to occur. Individuals behaved and responded differently depending on the type of interaction, serving both territorial and reproductive purposes. Temporal segregation allowed intersexual co-occurrence, while same-sex co-occurrence may be facilitated through familiarity with stable neighbours. Central individuals interacted within and outside their social unit and appeared fundamental to group stability. The removal of these individuals, such as through legal harvest or pre-emptively as an attempt to minimize depredation, may weaken social cohesion and ultimately affect population demography. Our findings on intraspecific co-occurrence in a solitary carnivore depict a complex social structure that can be important for population stability and might occur in other solitary species.

Spatial patterns of large African cats: a large-scale study on density, home range size, and home range overlap of lions Panthera leo and leopards Panthera pardus

Article

Full-text available

Mar 2023

Facilitation of a free-roaming apex predator in working lands: evaluating factors that influence leopard spatial dynamics and prey availability in a South African biodiversity hotspot

Article

Full-text available

Jan 2023

Apex predators ideally require vast intact spaces that support sufficient prey abundances to sustain them. In a developing world, however, it is becoming extremely difficult to maintain large enough areas to facilitate apex predators outside of protected regions. Free-roaming leopards ( Panthera pardus ) are the last remaining apex predator in the Greater Cape Floristic Region, South Africa, and face a multitude of threats attributable to competition for space and resources with humans. Using camera-trap data, we investigated the influence of anthropogenic land modification on leopards and the availability of their natural prey species in two contrasting communities—primarily protected (Cederberg) and agriculturally transformed (Piketberg). Potential prey species composition and diversity were determined, to indicate prey availability in each region. Factors influencing spatial utilisation by leopards and their main prey species were also assessed. Estimated potential prey species richness (Cederberg = 27, Piketberg = 26) and diversity indices (Cederberg— H′ = 2.64, Ds = 0.90; Piketberg— H′ = 2.46, Ds = 0.89), supported by both the Jaccard’s Index ( J = 0.73) and Sørensen’s Coefficient ( CC = 0.85), suggested high levels of similarity across the two regions. Main leopard prey species were present in both regions, but their relative abundances differed. Grey rhebok, klipspringer, and rock hyrax were more abundant in the Cederberg, while Cape grysbok, Cape porcupine, chacma baboon, and common duiker were more abundant in Piketberg. Leopards persisted across the agriculturally transformed landscape despite these differences. Occupancy modelling revealed that the spatial dynamics of leopards differed between the two regions, except for both populations preferring areas further away from human habitation. Overall, anthropogenic factors played a greater role in affecting spatial utilisation by leopards and their main prey species in the transformed region, whereas environmental factors had a stronger influence in the protected region. We argue that greater utilisation of alternative main prey species to those preferred in the protected region, including livestock, likely facilitates the persistence of leopards in the transformed region, and believe that this has further implications for human-wildlife conflict. Our study provides a baseline understanding of the potential direct and indirect impacts of agricultural landscape transformation on the behaviour of leopards and shows that heavily modified lands have the potential to facilitate mammalian diversity, including apex predators. We iterate that conservation measures for apex predators should be prioritised where they are present on working lands, and encourage the collaborative development of customised, cost-effective, multi-species conflict management approaches that facilitate coexistence.

At home or passing through? Leopard population and spatial ecology on a private game reserve

Article

Full-text available

Sep 2022

Estimating large carnivore population size and understanding how individuals share space is crucial for their conservation, even more so now they are increasingly restricted to small, fenced game reserves where active management is often required. Combining data from GPS collars and camera traps, we estimated population size for leopards (Panthera pardus) on Ongava Game Reserve, northern Namibia, and investigated their spatio-temporal use of waterholes. Over three years of camera trapping, we identified a total of 29 individuals (including 12 adult or sub-adult females and 15 adult or sub-adult males). Based on the time interval over which they were observed, we defined 10 of these individuals as resident (four adult or sub-adult males and six adult or sub-adult females). The remaining 19 individuals (66%) were classified as transient. During the same period, we deployed two GPS collars, one on a resident adult male, the other on a resident adult female. Home range sizes from GPS data were estimated at 193 km 2 for the male and 122 km 2 for the female. Based on home range overlap found in the literature, we estimated Ongava's resident population to be composed of 2-4 males and 3-6 females. We found no evidence of exclusive use of waterholes by individuals, suggesting an absence of spatial avoidance. Our work highlights the importance of taking social status (resident vs transient) into account and of using multiple methods when estimating population size of leopards.

Resource competition explains rare cannibalism in the wild in livebearing fishes

Article

Full-text available

May 2022

Cannibalism, the act of preying on and consuming a conspecific, is taxonomically widespread, and putatively important in the wild, particularly in teleost fishes. Nonetheless, most studies of cannibalism in fishes have been performed in the laboratory. Here, we test four predictions for the evolution of cannibalism by conducting one of the largest assessments of cannibalism in the wild to date coupled with a mesocosm experiment. Focusing on mosquitofishes and guppies, we examined 17 species (11,946 individuals) across 189 populations in the wild, spanning both native and invasive ranges and including disparate types of habitats. We found cannibalism to be quite rare in the wild: most populations and species showed no evidence of cannibalism, and the prevalence of cannibalism was typically less than 5% within populations when it occurred. Most victims were juveniles (94%; only half of these appeared to have been newborn offspring), with the remaining 6% of victims being adult males. Females exhibited more cannibalism than males, but this was only partially explained by their larger body size, suggesting greater energetic requirements of reproduction likely play a role as well. We found no evidence that dispersal‐limited environments had a lower prevalence of cannibalism, but prevalence was greater in populations with higher conspecific densities, suggesting that more intense resource competition drives cannibalistic behavior. Supporting this conclusion, our mesocosm experiment revealed that cannibalism prevalence increased with higher conspecific density and lower resource levels but was not associated with juvenile density or strongly influenced by predation risk. We suggest that cannibalism in livebearing fishes is rare in the wild because preying on conspecifics is energetically costly and only becomes worth the effort when competition for other food is intense. Due to the artificially reduced cost of capturing conspecifics within confined spaces, cannibalism in captive settings can be much more frequent. We assessed the occurrence of cannibalism in mosquitofishes (genus Gambusia) and guppies (Poecilia reticulata) by examining 17 species (11,946 individuals) across 189 populations in the wild, and by conducting a mesocosm experiment for one species (Gambusia affinis). Cannibalism was rare, its occurrence was associated with resource competition, but it was not associated with juvenile density or strongly influenced by predation risk, and cannibals were predominantly female. Cannibalism in captive settings might be higher due to an artificially reduced cost of capturing conspecifics within confined spaces.

Big competition for small spots? Conspecific density drives home range size in male and female leopards

Article

Nov 2021

Variation in home range size exists among and within wildlife populations. Home range size variation may be driven by both intrinsic and extrinsic factors, including sex, food and reproductive resources, density and competition. In this study, we investigated the sex‐specific impacts of prey and reproductive resources, conspecific density and competition on leopard Panthera pardus home range size at two spatio‐temporal scales in the Sabi Sand Game Reserve, South Africa. Male leopard home ranges were more than twice the size of those of females, in line with expectations for a solitary, polygamous species. Both male and female leopard space‐use were primarily driven by short‐term changes in intra‐sexual conspecific density. Females were influenced by both short and long‐term drivers, with long‐term prey availability (home range and core) and refugia (core) further impacting size. Males were almost exclusively influenced by short‐term drivers; home range size was further impacted by short‐term changes in female leopard and prey density, and age. Long‐term prey availability contributed to male leopard core size. The difference in impact of short‐ and long‐term drivers between the sexes likely relates to tenure expectations; males may be forced out of their territories at any time and should therefore optimize their space‐use based on present conditions. Female leopards, however, must secure a home range that maximizes their reproductive success in the short‐ and long‐term in order to raise cubs to independence. Our findings challenge expectations that space‐use is primarily resource‐driven and demonstrate the critical role of social factors in saturated populations of solitary species. Furthermore, we illustrate the importance of considering temporally variable factors across different timescales to fully understand their impact on mammalian spatial organization.

Effect of sex, age, and reproductive status on daily activity levels and activity patterns in jaguars (Panthera onca)

Article

Full-text available

Sep 2021

All animals, including carnivores, adapt their daily activity duration and distribution to satisfy food demands, breed, or avoid mortality risk. We used the kernel density method to estimate daily movement activity levels and movement activity patterns of jaguars in Hato Piñero, in Venezuelan Western Llanos, based on 3,656 jaguar detection time records from two and a half years of camera trapping. Jaguars were active for 11.7 h per day on average and exhibited mostly nocturnal and crepuscular activity pattern, however, with marked differences between sex/age/reproductive groups. Reproductive females had the highest daily activity level (13.2 h/day), followed by adult males (10.9 h/day), non-reproductive females (10.5 h/day), and cubs (8.7 h/day). Activity patterns also differed, with males and reproductive females having activity peaks at the same hours after sunset and before sunrise, cubs in the night and after sunrise, while non-reproductive females were most active during night hours. This study was the first to document the effect of sex, age, and reproductive status on daily level and activity pattern in the jaguar.

The effect of competing carnivores on the feeding behaviour of leopards (Panthera pardus) in an African savanna

Article

Full-text available

May 2021

Knowledge of competition dynamics among Africa’s large carnivores is important for conservation. However, investigating carnivore behaviour in the field can be challenging especially for species that are difficult to access. Methods that enable remote collection of data provide a means of recording natural behaviour and are therefore useful for studying elusive species such as leopards (Panthera pardus). Camera traps and Global Positioning System (GPS) collars are powerful tools often used independently to study animal behaviour but where their data are combined, the interpretation of a species’ behaviours is improved. In this study we used data from baited camera trap stations to investigate the feeding habits of leopards at Malilangwe Wildlife Reserve, Zimbabwe. We investigated the influence of spotted hyenas, lions and other competing leopards on the feeding duration of leopards using Generalized Linear Mixed Effects Modelling. To test the influence of competing predators on resting distances from bait sites, eight leopards were fitted with GPS collars. Results showed that leopards spent the shortest time feeding on the baits in the presence of competing male leopards compared to other predators while lion presence caused animals to rest farthest from bait sites. Interaction analysis indicated that small‐bodied leopards spent significantly shorter durations feeding when spotted hyenas were present. Our findings demonstrate that competition from guild carnivores has negative impacts on the food intake of leopards, which may have implications for fitness and survival. This study provides a snapshot of the competition dynamics at bait sites which may give insight to ecosystem level interactions among large carnivores in savanna ecosystems.

Population estimates of large carnivores and their conflict with humans in East Africa and India

Thesis

Full-text available

Aug 2020

Alexander Braczkowski

Humanity is exerting unprecendented pressure on natural ecosystems and the species living in them. This pressure is particularly evident among the larger members of the order Carnivora. Their large body size (typically in the 25-600 kg range), life history traits, and reliance on large prey species places them at increased risk of extinction. The International Union for the Conservation of Nature (IUCN) Cat Specialist Group, and the Convention of Migratory Species (CMS) both recognize the deficiencies in robust data available on large carnivores across large tracts of Africa. Furthermore, the population estimates we do have are often drawn from less-reliable methods. The overarching aim of this PhD thesis was to: 1) use a recently-developed population estimation technique (Elliot and Gopalaswamy 2017) to estimate the densities, population size, and population parameters of large carnivores in the Queen Elizabeth Conservation Area (QECA), Uganda, and use these data to inform their conservation status, 2) improve understanding of the conflict between large carnivores and human communities in Lake Mburo, Uganda, and Mumbai, India, and 3) explore alternative methods to fund conservation measures, including compensation and a wildlife imagery royalty. In Chapter 1 as part of introducing my thesis, I examined the literature on historic and present methods being used to census African lions Panthera leo and together with a team of international collaborators I made a case for the adoption of spatially explicit capture recapture (SECR) methods for African lions. In Chapter 2 I built upon this and showed the utility of using population state variables (namely movement, sex-ratios, and density) in assessing the conservation status of African lions in a poorly known area of East Africa. I used a population of African lions in south-western Uganda’s Queen Elizabeth Conservation Area (QECA), as a model. I conducted a 93-day African lion census in 2017-2018 and compared the results to those from an intensive radio-collaring study from a decade ago. I hypothesized that if the population of African lions in the QECA was stable or increasing, lion movement distances and home ranges would be similar between the two study periods but if movement distances were larger and sex-ratios were male-biased, the lion population was likely declining. I found male lions expanded their ranges by > 400%, and females >100%, overall lion densities were low (2.70 lions/100 km2, posterior SD=0.47), and the sex ratio of lions in the system was skewed towards males (1 female lion: 2.33 males), suggesting a decline. I concluded this chapter with a discussion of the practical conservation application of using this census technique in other parts of Africa, particularly where historic lion home-range data exist. In Chapter 3, I used the same spatially explicit capture recapture models on data collected from 74 remote camera traps set across the QECA to assess the population densities of African leopards and spotted hyenas in this savannah park. We surveyed the northern, and southern sections of the QECA, and estimated leopard densities to be 5.03 (range = 2.80–7.63), and 4.31 (range = 1.95–6.88) individuals/100 km2 respectively, while hyena densities were 13.43 and 14 individuals/100 km2. Estimates of hyena density were the highest recorded for the species anywhere within their range using SECR methods. I also suggested that the high hyena densities could be related to the evidence provided in Chapter 2 of African lion decline in the QECA. One hypothesis that could explain the inverse densities of hyenas and lions is that hyenas have experienced competitive release from African lions in the QECA. Similar findings have been reported in the Talek region of Kenya’s Maasai Mara, and Zambia’s Liuwa Plains. This chapter also provided the first SECR population estimates of leopards, and spotted hyenas anywhere in Uganda. In Chapter 4 and Chapter 5 I addressed the most important threat to the existence of large carnivores: conflict with human communities, and their livestock. While conflict tends to dominate the narrative where large carnivores and humans co-exist, there can often be direct and indirect benefits to humans. In Chapter 4 I examined the ecosystem services provided to people by the Indian leopard Panthera pardus fusca, in Mumbai.The Sanjay Gandhi National Park (SGNP) is located in the city of Mumbai, India, and has some of the highest human population densities in the world. Large carnivores are known to control prey populations, suppress smaller carnivores, reduce parasite load in humans, and promote seed dispersal. However, this chapter is one of the first studies highlighting the ecosystem services provided by a large carnivore outside of a natural or protected system. I showed that leopard predation on stray dogs reduced the number of people bitten by dogs, reduced the risk of rabies transmission, and reduced dog sterilization and management costs. Our estimates showed that dog densities around SGNP (17.3/km2) were 40 times lower than four nearby urban informal settlements (688/km2) and were ten times lower than the citywide mean (160/km2). If it is, as we propose, leopards that are holding the dog population around the park at its current density, dog bites could increase from 3.6 bites/1000 people to 15.5 bites/1,000 people if leopards were to disappear. As over 78% of dog bites in Mumbai require treatment, and 2% require rabies post-exposure vaccination, the treatment costs could reach as high as US$ 200,000 per year (compared to ~US$ 42,500 currently). As development pressures are threatening the region’s leopards, this work shows the potential costs of their local extirpation. Chapter 5 assesses the landscape-level correlates of livestock attacks by two large carnivores, the spotted hyena, and African leopard in the cattle and sheep/goat farms bordering Lake Mburo National Park, south-western Uganda. I also make suggestions on how to improve the sustainability of a voluntary financial compensation scheme run by a local lodge (the Mihingo Conservation Fund) aimed at alleviating persecution of these species. I used ten years of depredation events to investigate the importance of seasonality and landscape features (ie. terrain ruggedness, proximity to roads, water, human settlements, and vegetation density) on livestock attack probability. I also examined the current costs of the compensation scheme of reported attacks. I showed that most livestock attacks in this region were caused by spotted hyenas, both predators killed at night, did not exhibit seasonal patterns in depredation, and attacks were owed to poorly fortified bomas (82% of leopard attacks and 64% of hyena attacks were made inside bomas). Attacks were also made near human settlements, close to the national park border, and in areas of rugged terrain. The compensation fund made more gross income from tourism activities than was paid in compensation in most years, but compensation costs had to be subsidised by the lodge because the funding was also used in other community development projects (eg. building of a school, and paying children’s school fees). Chapter 6 of this thesis built upon the sub-theme of Chapter 5, funding of carnivore conservation measures and created a roadmap for a recently proposed idea of a threatened wildlife imagery royalty to stem the large budgetary shortfalls facing large carnivore conservation. The idea of a threatened species imagery royalty was proposed in two recent papers, Good et al. (2017) and Courchamp et al. (2018). I built upon these and discussed how such a royalty could be implemented, explored several legal avenues for its application, and also showed its potential scale in leveraging funding. The creation of a national law which charges a royalty from corporations using the imagery of their threatened wildlife, and a “Fairtrade” equivalent held the most promise for the development of a wildlife imagery royalty. Indeed, articles 3 and 6 of the Convention on Biological Diversity (CBD) encourage sovereign states to ensure activities within their jurisdiction and control do not damage the environment of other states. Similarly they are encouraged to develop national strategies, plans or programs for the conservation and sustainable use of biological diversity. The funding that could potentially be leveraged from a wildlife imagery royalty is immense. I used large felids as a model group to show that the relevant 14 companies on the Forbes 2000 list alone could generate US$ 202 million–2.02 billion if they paid 0.1-1% of their profits in royalties. My thesis addressed an important but often overlooked component of estimating large carnivore populations, the use of population state variables in informing conservation status. The use of animal movement, sex-ratio, and density information has wide application that transcends large carnivores. My assessment of leopard-dog interactions, and the potential implications for humans, was one of the first examples in the literature of the potential benefits a large carnivore may have to humans. The assessments of compensation and wildlife imagery royalties have important consequences on better managing and also leveraging funding for the conservation of large carnivores and other threatened, enigmatic species.

Insights into giant armadillo (Priodontes maximus Kerr, 1792) reproduction

Article

Full-text available

Sep 2019

This paper presents unique data on the reproductive behavior of the rare giant armadillo ( Priodontes maximus ), including gestation, inter-birth intervals, number of offspring and parental care. It also describes a potential non-parental infanticide. The study used telemetry, camera traps and track observations for over 7 years in a 300-km ² area in the central Brazilian Pantanal. Females with young were recorded 5 times. Reproductive events did not appear to be seasonal. A 5-month gestation period was estimated. Parental care is long, as the offspring is completely dependent on its mother’s milk until 6–8 months of age. Weaning was estimated to occur at 11–12 months, but the offspring continued to be dependent on its mother’s burrows until 18 months old. Three births were recorded over a 6-year period for one individual. The offspring from the first birth recorded was killed at 4 weeks of age in a potential infanticide, but 7 months after the first birth, a second offspring was born. A third birth was recorded 3 years after the second birth. Results from this study suggest that the population growth rate of giant armadillos is very low and the species can therefore easily be locally extirpated.

Breeding pattern of wildcat Felis silvestris (Schreber, 1777) studied in captivity in the iberian peninsula

Article

Full-text available

Dec 2018
HYSTRIX

We studied the effect of several environmental and reproductive variables on the reproductive performance of captive European wildcat (Felis silvestris silvestris, Schreber 1777) females in Spain. We collected reproductive data from 34 females that produced 77 litters and 295 kittens. The youngest females that gave birth were 12 months old, whereas the oldest was11+ years old. On average, females giving birth were 3.8 years old (n=62), with a mode of one+ years old. Mean litter size was 3.7 kittens±1.0 (range: one to six; n=77 litters), with three or four kittens comprising 67.

Behavioural and pathological insights into a case of active cannibalism by a grey seal (Halichoerus grypus) on Helgoland, Germany

Article

Full-text available

Mar 2019
J SEA RES

First reports on cases of grey seal predation on other marine mammals from different parts of Europe have been published in recent years, but few cases provide sufficient detail. Here we report a case of active cannibalism by a grey seal, which has been witnessed and recorded in detail on the German island of Helgoland, describing particular behavioural aspects and lesions. In March 2018, a subadult male grey seal was observed catching, killing and feeding extensively from a juvenile grey seal. The carcass showed severe cutaneous lacerations, starting in the head region and following around the trunk in a circular pattern. These results are discussed with regard to the previously reported cases to form a solid knowledge base for retrospective and future assessments of carcasses potentially subjected to grey seal predation. The correct assignment of predated seals is important to determine the potential influence this behaviour may have on seal populations.

Reintroducing apex predators: the perils of muddling guilds and taxocenoses

Article

Full-text available

Jul 2018

Everton Miranda

Computer Assisted Sperm Analysis (CASA) in the Critically Endangered Captive Arabian Leopard (Panthera pardus nimr): A Multivariate Clustering Analysis

Article

Full-text available

Jan 2018

Rationale: Big felids including the Panthera genus are under tremendous stressful conditions that threaten the very existence of wild populations around the world. Survivability is commonly linked to numerous factors such as poaching, habitat fragmentation, inbreeding depression and lack of prey. A crucial element that is used to mitigate endangerment risk is the enhancement of reproductive performance with the use of assisted reproductive technologies. Amongst them is computer assisted sperm analysis (CASA) that digitally evaluates the kinematics of individual spermatozoa. Regrettably, this powerful tool is overlooked in all big felids due to the lack of a universal setting.Objective: To conduct a comparative CASA with several species modules and to deploy it for the first time in the critically endangered Arabian leopard.Results: The progressive motility was variable amongst all settings, whereby the highest in the bovine standard (82.9%), lowest in the stallion setting (12%), subjective (85%) and average at 50.1%. The combination of all motility parametrics, indicate a progressive joining of two minor and two major clusters with a very high distance of 93% and a linkage space of approximately 42%. This in turn demonstrate notable divergence of two important kinematic settings.Conclusion: The current study illustrates the inconsistent and incompatible readings amongst various CASA species modules. This affirms the urgent need to establish CASA exclusively customized for the Panthera genus to maximize the reproductive potential.

Intraspecific killing among Leopards (Panthera pardus) in Iran (Mammalia: Felidae)

Article

Full-text available

Apr 2018

Intraspecific aggression is one of the most common causes of death in leopards. Here, we report four cases of intraspecific killing amongst Persian Leopards (Panthera par-dus saxicolor) in Iran. A young male leopard was found on 7 June 2008 which, according to camera trap images, had been killed by an adult male over a Red Deer (Cervus elaphus) kill, with trauma to his neck in Dorfak No-Hunting Area. A young female that had been fitted with a satellite GPS collar on 6 December 2015 in Tandoureh National Park died on 29 January 2016 at a site where an Urial Sheep (Ovis orientalis) ram had been freshly killed. Necropsy results, footprints at the scene of death and camera trap footage all supported the deduction that the animal was killed by a larger female leopard at the kill site. On 13 January 2017, a young, partially eaten female leopard was found with double puncture on the side of her throat. Finally, a rehabilitated adult female fitted with a satellite GPS collar found on 19 December 2017 with a double puncture on her head with several trauma and haemorrhages on her back. These instances seem to be the first documented reports of intraspecific killing among free-ranging leopards in Asia.

Infanticide in a mammal-eating killer whale population

Article

Full-text available

Mar 2018

Infanticide can be an extreme result of sexual conflict that drives selection in species in which it occurs. It is a rarely observed behaviour but some evidence for its occurrence in cetaceans exists in three species of dolphin. Here we describe observations of an adult male killer whale (Orcinus orca) and his postreproductive mother killing a neonate belonging to an unrelated female from the same population in the North Pacific. This is the first account of infanticide reported in killer whales and the only case committed jointly by an adult male and his mother outside of humans. Consistent with findings in other social mammals, we suggest that infanticide is a sexually selected behaviour in killer whales that could provide subsequent mating opportunities for the infanticidal male and thereby provide inclusive fitness benefits for his mother.

Interbirth intervals are associated with age of the mother, but not with infant mortality in Indian rhinoceroses

Article

Full-text available

Jun 2017

Rhinoceroses are among the most endangered mammals in the world. Despite a recent increase in numbers in most wild populations, poaching or political instability may exterminate large populations very quickly. Therefore, captive or ex situ rhinoceros populations can play an important role in their conservation. Previous studies identified infant mortality and interbirth intervals among the main parameters affecting the viability and survival of rhinoceros populations. In our study, we tested the recently suggested prediction that in captive Indian rhinoceros Rhinoceros unicornis, longer interbirth intervals may result in higher infant mortality. We also examined the factors that are the main predictors of infant mortality and interbith intervals using the studbook data on Indian rhinoceros born in zoos worldwide as well as data from Dudhwa National Park, India, where rhinoceroses were successfully reintroduced. We found no association between interbirth intervals and infant mortality. In both populations, the main predictor of infant mortality was mother's parity, with higher mortality in calves born to primiparous mothers. In addition, we found that the interbirth intervals were shorter in zoos than in Dudhwa and that they increased with increase in age of the mother, which was the only factor affecting interbirth interval in both populations. Our results show that the same factors affect both parameters in both populations and thus illustrate that the reproduction and infant survival of Indian rhinoceros in zoos reflect the natural pattern. Furthermore, we suggest that in captivity, the interbirth intervals could be slightly prolonged to approach the situation in the wild.

Resource selection by leopards (Panthera pardus) in a landscape mosaic in northern West Bengal

Thesis

Full-text available

Oct 2014

Aritra Kshettry

Exploring paleo food-webs in the European Early and Middle Pleistocene: A network analysis

Article

Full-text available

Nov 2015
QUATERN INT

Food webs are networks of feeding (trophic) interactions among species. As any other network approach, research on food webs focuses its analysis on the structure of direct and indirect interactions among diverse species, rather than looking at the particularities of certain taxa. In recent times, scholars have collected an impressive amount of empirical food-web data to study present day terrestrial and aquatic habitats.More restrictively, this approach has also been applied to trophic interactions represented in the fossil record of extinct ecosystems. Nevertheless, to our knowledge, none of them has addressed the role played by the different Pleistocene hominin species as part of such food-webs. In this work, we aim at filling this gap by focusing on the Early and Middle Pleistocene paleo-communities in Western Eurasia. Our goal is to improve our understanding on changes experienced by large mammals' interactions during this period, and shed some light on the influence of and on Homo species of those changes.We have constructed up to 27 paleo food-webs from the archaeo-paleontological record of European assemblages, covering from the Middle Villafranchian to the Late Galerian. Only large mammals have been considered, including a couple of Homo species that are present in 8 food-webs. Then, we have developed a two-steps analysis. First, we have calculated the main structural features of all the networks, and have compared them across geographical areas, periods and cases with and without Homo species. Second, we have calculated different structural centrality measures in order to assess the relevance of Homo species in their corresponding food-webs.The obtained results show that the Pleistocene food webs under study shared basic features with modern food webs, although differences in the values of some parameters might be significant. Moreover, when comparing the networks across periods, we found a marked change that could be related to the Mid-Pleistocene Revolution. Finally, our results also highlight the trophic position of hominins in the web as a central species that channeled energy fluxes.

The Role of Scent Marking in Mate Selection by Female Pumas (Puma concolor)

Article

Full-text available

Oct 2015
PLOS ONE

Mate selection influences individual fitness, is often based on complex cues and behaviours , and can be difficult to study in solitary species including carnivores. We used motion-triggered cameras at 29 community scrapes (i.e. scent marking locations used by multiple individuals) and home range data from 39 GPS-collared pumas (Puma concolor) to assess the relevance of communication behaviours for mate selection by female pumas in Califor-nia. Female pumas visited community scrapes irregularly and visitation bouts appeared to be correlated with oestrus. Female pumas on average selected from 1.7 collared males, and selection was based on multiple cues that varied among the different time periods measured (i.e. the female's visitation bout and in 90 days previous to the consorting event). Female mate selection over the course of a visitation bout was based on frequency of the male visitation, mass, and age. In the 90 days previous to consorting, the number of scrapes a male created was the most important contributor to selection, which was likely related to his residency status. We also found that at least 14% of females mated with multiple males, thus possibly confusing paternity. Our findings provide a mechanistic understanding of how female pumas use scent and auditory communication at community scrapes to select dominant resident males to mate with.

Just a cat fight or something more sinister? Infanticide is rare among female leopards

Article

Full-text available

Jul 2023
ECOLOGY

Spatial patterns of large African cats: a large‐scale study on density, home range size, and home range overlap of lions Panthera leo and leopards Panthera pardus

Article

Full-text available

Mar 2023

Spatial patterns of and competition for resources by territorial carnivores are typically explained by two hypotheses: 1) the territorial defence hypothesis and 2) the searching efficiency hypothesis. According to the territorial defence hypothesis, when food resources are abundant, carnivore densities will be high and home ranges small. In addition, carnivores can maximise their necessary energy intake with minimal territorial defence. At medium resource levels, larger ranges will be needed, and it will become more economically beneficial to defend resources against a lower density of competitors. At low resource levels, carnivore densities will be low and home ranges large, but resources will be too scarce to make it beneficial to defend such large territories. Thus, home range overlap will be minimal at intermediate carnivore densities. According to the searching efficiency hypothesis, there is a cost to knowing a home range. Larger areas are harder to learn and easier to forget, so carnivores constantly need to keep their cognitive map updated by regularly revisiting parts of their home ranges. Consequently, when resources are scarce, carnivores require larger home ranges to acquire sufficient food. These larger home ranges lead to more overlap among individuals' ranges, so that overlap in home ranges is largest when food availability is the lowest. Since conspecific density is low when food availability is low, this hypothesis predicts that overlap is largest when densities are the lowest. We measured home range overlap and used a novel method to compare intraspecific home range overlaps for lions Panthera leo ( n = 149) and leopards Panthera pardus ( n = 111) in Africa. We estimated home range sizes from telemetry location data and gathered carnivore density data from the literature. Our results did not support the territorial defence hypothesis for either species. Lion prides increased their home range overlap at conspecific lower densities whereas leopards did not. Lion pride changes in overlap were primarily due to increases in group size at lower densities. By contrast, the unique dispersal strategies of leopards led to reduced overlap at lower densities. However, when human‐caused mortality was higher, leopards increased their home range overlap. Although lions and leopards are territorial, their territorial behaviour was less important than the acquisition of food in determining their space use. Such information is crucial for the future conservation of these two iconic African carnivores.

Relaxed territoriality amid female trickery in a solitary carnivore

Article

Dec 2022
ANIM BEHAV

Territoriality (the defence of exclusive home ranges) is a strategy utilized within mammal populations to maximize individual fitness by monopolizing available resources. There is a trade-off, however, between acquiring the resources necessary for survival and reproduction and the cost of defending their exclusive use. Clarifying the sociospatial organization of wildlife populations is vital for understanding intraspecific competition and reproductive behaviour and, ultimately, conserving vulnerable or endangered species. We evaluated territorial behaviour in a solitary carnivore, the African leopard, Panthera pardus, under high-density conditions. We also assessed the influence of resource availability, sex-specific mating tactics and kinship on space sharing within the observed sociospatial structure. Both male and female leopards exhibited relaxed territoriality, with considerable intrasexual overlap occurring among both sexes, indicative of a risk aversion strategy. The risk of serious injury or death due to frequent territorial altercations in such a high-density system negated the benefits of strict spatial boundaries. Space sharing occurred more frequently in resource-rich areas: males overlapped more commonly in areas with high female density, and males and females overlapped more commonly in areas of high prey density. Males competed for access to females rather than monopoly of their home ranges; we hypothesize that the extralimital mating excursions undertaken by female leopards probably reduce the benefit of female monopoly (and consequently, of female defence) in this polygamous species. Space sharing among females was primarily driven by kinship; related females exhibited greater overlap than unrelated females, suggesting kinship benefits to space sharing among mother–daughter pairs. The contributions of resource availability, sex-specific mating tactics and kinship towards creating conditions permitting relaxed territoriality illustrate the complexity of ecological, demographic and behavioural factors involved in the sociospatial organization of solitary carnivores.

Assessment of leopard translocations in South Africa

Article

Full-text available

Jul 2022

Translocations are commonly employed to mitigate human–carnivore conflict but rarely evaluated, resulting in conflicting reports of success, particularly for leopards (Panthera pardus). We evaluate the status of available leopard translocation data, the factors driving the intentional removal of leopards, and the potential causal factors associated with successful and failed translocation events. We obtained data on 60 leopard translocation events across five provinces in South Africa between 1994 and 2021. We considered a successful translocation outcome when (1) the animal was moved outside of its original home range, (2) the animal established a new home range away from the capture site, (3) no substantive livestock losses were linked to the translocated animal in the post-release monitoring period, and (4) the animal survived at least 6 months post-translocation. If mortality occurred due to factors that were equally likely to impact resident individuals and were unrelated to the translocation event (e.g., poaching), the event was not considered a failed effort. Most translocations were the result of human–carnivore conflict (HCC; 82%, n = 49), stressing the high prevalence of HCC and the importance of advocating preventative conflict mitigation efforts to conserve leopards. The leopards were moved distances from 2.5 to 196.3 km (63.3 ± 51.7km). Forty (67%) translocation events had unknown outcomes, indicating the limited data available on translocation outcomes. This also indicates the disparity in the objectives of translocations by various entities involved with translocations and suggests that monitoring be a prerequisite for future translocations. Twenty events offered reliable outcomes by means of post-event monitoring, with seven (12%) considered successful, with three (5%) as failures, and with four (7%) not moved beyond their original home ranges, while six (8%) ended in unrelated deaths. The failed events were attributed to inter/intra-specific competition, and one animal returned to its original home range after a translocation distance of 68 km. Translocation success was strongly explained by translocation distance. We found that damage-causing leopards were successfully translocated under specific conditions, and longer translocation distances increase success. Translocations are commonly employed but are still poorly monitored. We discuss basic standardized protocols to improve future leopard translocations (including pre- and post-monitoring) while advocating alternative non-lethal practices to reduce the prevalence of human–carnivore conflict.

Design and ecological applications of the baited-camera trapping method of censusing leopards in a savanna ecosystem

Thesis

Full-text available

Nov 2021

Allan Tarugara

Determining populations of leopards (Panthera pardus) is important for both their conservation and also that of their prey. Camera-trapping has emerged as a powerful and non-invasive tool for studying carnivores in their natural habitats especially for species that are elusive or occur at low densities such as leopards. This thesis presents the Baited-Camera Trapping (BCT) method of censusing leopards, a Zimbabwean conceived design modification of the conventional unbaited setup. This method has been documented to improve capture rates and provide robust and novel data for leopard surveys in savanna environments. This study used single cameras coupled with bait to survey a population of leopards at Malilangwe Wildlife Reserve (MWR), a privately owned medium-sized property in south-eastern Zimbabwe. The objectives of the study were to: (1) conduct a cost-benefit analysis to determine the optimal density and exposure length of baits for censusing leopards at MWR, (2) develop a technique for estimating body dimensions of leopards from camera trap photographs, (3) determine the influence of competing carnivores on the feeding habits of leopards in a savanna ecosystem, and (4) to review the application of the BCT method in comparison with conventional camera trapping. Data were collected from July 2017 to January 2018 and the CAPTURE software was used for population size analysis and the Statistical Package for Social Scientists were used for cost-benefit analyses. Generalized Linear Mixed Effects Modelling, performed using the R statistical software, was used to compare actual and photograph based body measurement data as well as to analyze the influence of competing predators on feeding duration and resting distances of leopards at bait stations. This study estimated the leopard population at MWR at 61 (61-67) individuals and concludes that using BCT stations at a density of 0.24 cameras km-2 km for 9 days is the optimal and cost-effective sampling effort required to provide reliable population statics in semi-arid savannas. The study established that the type of body measurement and the posture of a leopard in a photograph had a significant influence on the accuracy of image-based measurements. Body length measurements taken from the level back-straight forelimb-parallel tail posture were the most accurate [mean error = 2.0 cm (1.5-2.7 cm)] while head-to-tail and tail length measurements and variations from the level back-straight forelimb-parallel tail posture did not provide sufficient accuracy. The findings also showed that the presence of male leopards at feeding locations was associated with shorter feeding durations while lion presence caused feeding leopards to wait longer from bait sites. The thesis provides the first published record of the BCT method outlining a step-by-step procedure for replication by other researchers and a comparative review of the method with traditional survey approaches. The findings in this thesis underscore the ability of BCT method to investigate multiple leopard population ecology questions which enhances its cost-benefit ratio. Furthermore, the method provides new information which can broaden the scope of research and inform management and policy direction. It is recommended that (i) researchers and managers incorporate cost-benefit analysis in their work as this is essential for informing effective application of effort and resources, (ii) researchers take advantage of the BCT method to collect behaviour and morphological data for species that are less understood such as leopards to maximize on the capital investment, (iii) managed wildlife areas that contain leopards consider the uptake of the BCT techniques as a wide encompassing population monitoring option, and (iv) regulatory authorities that supervise hunting operations such as the Zimbabwe Parks and Wildlife Management Authority adopt the BCT technique to enhance their information management portfolios and quota setting for sustainable harvest practises.

Intraspecific interactions in a high density leopard population

Article

Full-text available

Nov 2021

Although less studied than interspecific interactions, interactions among members of the same species can influence space use and temporal activity. Using techniques commonly applied to the analysis of interspecific interactions – multi-species occupancy modelling and the analysis of temporal activity patterns – we studied intraspecific interactions within a high density population of Persian leopards (Panthera pardus saxicolor) in Tandoureh National Park, northeastern Iran. Using camera trap data, we investigated spatiotemporal interactions between male leopards, lone female leopards and families (cubs / females with cubs). While we hypothesised that male and female leopards would display different temporal activity patterns, we did not predict spatial avoidance between these groups. We also predicted that leopard families would exhibit spatiotemporal avoidance from male leopards due to the risk of infanticide. Contrary to our expectations we did not find any evidence for spatial or temporal avoidance between leopard families and adult male leopards. Male and lone female leopards exhibited positive pairwise co-occurrence, consistent with reports of high overlap between male and female leopard home ranges. While a high level of overlap in temporal activity patterns was found between males/lone females and males/families, there was evidence for variation in the proportion of time each leopard group was active in particular periods of the diel cycle. Male leopards showed cathemeral activity, while lone females and families were more active during daylight hours. The application of these techniques to interactions within a species has improved understanding of the ecology and behaviour of this endangered solitary carnivore.

Infanticide by Females Is a Leading Source of Juvenile Mortality in a Large Social Carnivore

Article

Jul 2021

Social animals benefit from their groupmates, so why do they sometimes kill each other's offspring? Using 30 years of data from multiple groups of wild spotted hyenas, we address three critical aims for understanding infanticide in any species: (1) quantify the contribution of infanticide to overall mortality, (2) describe the circumstances under which infanticide occurs, and (3) evaluate hypotheses about the evolution of infanticide. We find that infanticide, although observed only rarely, is in fact a leading source of juvenile mortality. Infanticide accounted for 24% of juvenile mortality, and one in 10 hyenas born in our population perished as a result of infanticide. In all observed cases of infanticide, killers were adult females, but victims could be of both sexes. Of four hypotheses regarding the evolution of infanticide, we found the most support for the hypothesis that infanticide in spotted hyenas reflects competition over social status among matrilines.

Repatriating leopards into novel landscapes of a South African province

Article

Full-text available

Feb 2021

1. Leopards are often translocated away from where they are caught as non‐lethal human‐wildlife conflict mitigation. It is alleged that leopards fail to settle where they are translocated to, owing to territoriality. We address the need to publish more accounts of successful repatriation of leopards, but also include novel applications aimed at orphans and confiscated leopards. 2. We satellite collared 16 leopards which included a mixture of relocated and translocated leopards, of which the latter included conventional damage causing animals (DCAs, viz ‘problem animals’), orphans and confiscations. We determined standard home‐range metrics and assessed home‐range stabilization as a means of determining site fidelity. Premature mortality and site infidelity, that is homing back to origins, were considered failures. We looked at range stabilization by examining successive monthly ranges against that of the preceding month, that is utilization distribution overlap indices (UDOIs). 3. Relocations turned out to be residents (˜3 km, n = 3), while they were immune to intervention, while translocations resulted in 50% success (n = 12), which were invariably confiscated adults of unknown origin, and simulations of natal dispersals of orphans (˜25 km, n = 3). DCAs never settled where released (˜90 km, n = 5). Resident leopards showed high monthly UDOIs, and for those translocated a minimum of 0.15 was benchmarked to suggest range stability, which also reflected large spatial ranging. 4. Success in home‐range establishment was associated with landscapes which were unsaturated by other leopards, but anthropogenic threats still persisted, such that survival after a year was ˜45%, but was not different to the normal background mortality of areas outside protected areas in the country. Operations are costly, particularly that to do with veterinary treatment, immobilization, collars and temporary keeping, but such costs can be carried by public interest groups. 5. All adults (>3 years) of known origin should be relocated (transported distance < home‐range diameter), while subadults (1–3 years) can be considered for translocations (transported distance > home‐range diameter), while heeding ecological and genetic considerations, and not exceeding ˜400 km. Other non‐lethal mitigation should however be considered before translocation of leopards is contemplated. These findings can be applicable to solitary felids with a similar social organization.

Observations of intraspecific killing, cannibalism, and aggressive behavior among polar bears (Ursus maritimus) in the eastern Barents Sea and the Kara Sea

Article

Nov 2020
POLAR BIOL

The ability of the polar bear (U. maritimus) to kill and consume conspecifics is accepted, but the reasons behind this behavior and its prevalence remain unclear. Here, we report 14 cases of intraspecific killing, cannibalism, and aggressive behaviors among polar bears observed in seven instances in the Barents Sea and the Kara Sea on Frans-Josef Land, Novaya Zemlya, and Vize Island. All but one of the observations were made on land during the ice-free season. Perpetrators, when observable , were mostly thin. The hunger resulting from a failure to gain fat reserves in spring appears to motivate perpetrators, while bear aggregation on islands could facilitate successful intraspecific killing. Surprisingly, cases of intraspecific killing were observed even in years when sea-ice conditions in the previous spring were relatively good. In one case, the killing of a cub of the year in the spring by a large, fat male could hardly be explained by nutritional demands. This could be a case of sexually selected infanticide, as the killing of cubs during the mating season increases the male's opportunity to breed.

Parturition dates in wild Eurasian lynx: evidence of a second oestrus?

Article

Full-text available

Jun 2020

Understanding reproductive physiology of a species is important to assess their potential to respond to environmental variation and perturbation of their social system during the mating or pre-mating seasons. We report 175 parturition dates from wild Eurasian lynx (Lynx lynx) in Scandinavia. Most lynx birth dates were highly synchronised around a mean of 30th May (SD = 9 days) with 173 of the 175 births ranging from May 2nd to June 30th. We detected two very late births on July 29th and August 15th in the absence of any indication that the females had given birth and lost a litter earlier in the year. We propose that these represent evidence of a second oestrus which is highly unusual in lynx because of their unique reproductive physiology. The rarity of these late season births has implications for lynx demography and social organisation.

Proximity to humans is associated with longer maternal care in brown bears

Article

Full-text available

Nov 2019
BEHAV ECOL SOCIOBIOL

In the sexual conflict over the duration of maternal care, male mammals may improve their reproductive success by forcing early mother–offspring separation in species where lactation supresses estrus. However, when individual females benefit from continuing to care for their current offspring, they should adopt counter-strategies to avoid separation from offspring. Here, we tested whether spatial segregation from adult males and proximity to humans during the mating season could be associated with longer maternal care in the Scandinavian brown bear (Ursus arctos). Using resource selection functions (RSFs), we contrasted habitat selection patterns of adult males and those of adult females with yearlings that either provided 1.5 years of maternal care (“short-care females”) or continued care for an additional year (“long-care females”) during the mating season, the period when family break-ups typically occur. Males and short-care females had similar habitat selection patterns during the mating season. In contrast, habitat selection patterns differed between males and long-care females, suggesting spatial segregation between the two groups. In particular, long-care females used areas closer to human habitations compared with random locations (defined here as selection), whereas males used areas further to human habitations compared with random locations (defined here as avoidance). Our results show a correlation between habitat selection behavior and the duration of maternal care. We suggest that proximity to humans during the mating season may represent a female tactic to avoid adverse interactions with males that may lead to early weaning of offspring. Significance statement In mammalian species where lactation supresses ovulation, males may gain a reproductive advantage by forcing early mother-offspring separation; however females can respond through behavioral tactics. We show that female brown bears with yearling cubs can spatially segregate from males during the mating season and that this behavior is associated with longer maternal care. Females selecting areas close to human habitations tend to keep their yearlings for an additional year, suggesting that human presence could have a shielding effect from males. Our study is among the few to explore sexual conflicts over the duration of maternal care close to weaning and shows that animals have the potential to adjust their behavioral tactics to make use of human-dominated landscapes.

Big cats at large: Density, structure, and spatio-temporal patterns of a leopard population free of anthropogenic mortality

Article

Feb 2019

Human impact is near pervasive across the planet and studies of wildlife populations free of anthropogenic mortality are increasingly scarce. This is particularly true for large carnivores that often compete with and, in turn, are killed by humans. Accordingly, the densities at which carnivore populations occur naturally, and their role in shaping and/or being shaped by natural processes, are frequently unknown. We undertook a camera‐trap survey in the Sabi Sand Game Reserve (SSGR), South Africa, to examine the density, structure and spatio‐temporal patterns of a leopard Panthera pardus population largely unaffected by anthropogenic mortality. Estimated population density based on spatial capture–recapture models was 11.8 ± 2.6 leopards/100 km². This is likely close to the upper density limit attainable by leopards, and can be attributed to high levels of protection (particularly, an absence of detrimental edge effects) and optimal habitat (in terms of prey availability and cover for hunting) within the SSGR. Although our spatio‐temporal analyses indicated that leopard space use was modulated primarily by “bottom‐up” forces, the population appeared to be self‐regulating and at a threshold that is unlikely to change, irrespective of increases in prey abundance. Our study provides unique insight into a naturally‐functioning carnivore population at its ecological carrying capacity. Such insight can potentially be used to assess the health of other leopard populations, inform conservation targets, and anticipate the outcomes of population recovery attempts.

Flexibility in the duration of parental care: Female leopards prioritise cub survival over reproductive output

Article

Jun 2017
J ANIM ECOL

Deciding when to terminate care of offspring is a key consideration for parents. Prolonging care may increase fitness of current offspring, but it can also reduce opportunities for future reproduction. Despite its evolutionary importance, few studies have explored the optimal duration of parental care, particularly among large carnivores. We used a 40‐year dataset to assess the trade‐offs associated with the length of maternal care in leopards in the Sabi Sand Game Reserve, South Africa. We compared the costs imposed by care on the survival and residual reproductive value of leopard mothers against the benefits derived from maternal care in terms of increased offspring survival, recruitment and reproduction. We also examined the demographic and ecological factors affecting the duration of care in the light of five explanatory hypotheses: litter size, sex allocation, resource limitation, timing of independence and terminal investment. Duration of care exhibited by female leopards varied markedly, from 9 to 35 months. Mothers did not appear to suffer any short‐ or long‐term survival costs from caring for cubs, but extending care reduced the number of litters that mothers could produce during their lifetimes. Interestingly, the duration of care did not appear to affect the post‐independence survival or reproductive success of offspring (although it may have indirectly affected offspring survival by influencing dispersal distance). However, results from generalised linear mixed models showed that mothers prolonged care during periods of prey scarcity, supporting the resource limitation hypothesis. Female leopards also cared for sons longer than daughters, in line with the sex‐allocation hypothesis. Cub survival is an important determinant of the lifetime reproductive success in leopards. By buffering offspring against environmental perturbation without jeopardising their own survivorship, female leopards apparently “hedge their bets” with current offspring rather than gamble on future offspring which have a small probability of surviving. In many species, parents put their own needs before that of their offspring. Leopard mothers appear sensitive to their offspring's demands, and adjust levels of care accordingly.

Population recovery highlights spatial organization dynamics in adult leopards

Article

Full-text available

May 2016
J ZOOL

Polygynous species follow sex-specific spacing patterns to maximize reproductive success, and changes in population density under otherwise stable environmental conditions likely provoke sex-specific responses in spacing patterns. A classical dual reproductive strategy hypothesis posits that female home range size and overlap are set by habitat productivity and remain stable under increasing population density, whereas male home range size and overlap decrease with increased mate competition. An alternative dispersal-regulated strategy predicts that females relinquish part of their home range to philopatric daughters and form matrilineal clusters, while adult male spacing is stable with density-dependent subadult male emigration rates. We used 11 years of telemetry data to assess the response of adult leopard Panthera pardus spacing following the release of harvest pressure. Female annual home ranges and core areas were smaller than in males. Intersexual overlap was larger than intra-sexual overlap in males or in females. As leopard density increased, female home range size and inter-annual fidelity in home range use decreased, and females formed matrilineal kin clusters. In contrast, male leopards maintained large home ranges, and did not track female home range contraction. Spacing dynamics in adult leopards was consistent with dispersal-regulated strategies, and did not support a classical dual reproductive strategy. Our study suggests possible hidden lag effects of harvest disturbance on spacing dynamics that are not necessarily apparent when only assessing demographic recovery of harvested populations.

The susceptibility of leopards (Panthera pardus) to trophy hunting

Thesis

Full-text available

May 2014

Alexander Braczkowski

The trophy hunting of African leopards Panthera pardus pardus may generate revenue to help foster their conservation. However, leopards are sensitive to hunting and populations decline if overharvested. The practice therefore requires careful management grounded in robust estimates of population density/status. Camera-trap surveys are commonly used to establish leopard numbers, and may guide harvest quotas. However, such surveys are limited over wide spatial scales and many African governments lack resources to implement them. In this thesis I explore the potential use of a harvest composition scheme applied to puma Puma concolor in North America, to monitor leopards. The method hinges on the susceptibility of different leopard cohorts to hunting and if this varies, then predictions can be made about harvest composition. Susceptibility is likely to be governed by space use, encounter rates with bait lures (a common method used to attract leopards to hunting hides) and hunter selectivity. Thus in this thesis I explore leopard susceptibility to these factors using a protected leopard population in northern Zululand, South Africa. In my first chapter I examine using scent lures in camera-trapping. Against a backdrop of a passive survey I show adult males, females and sub-adults are captured at similar rates compared to a passive survey using lures. The use of lures does not appear to violate closure assumptions or affect spatio-temporal patterning, but their use appears limited as density estimate precision is not improved. My second chapter examines ecological (likelihood of encountering a hunter) and anthropogenic (attractiveness to hunters) susceptibility of leopards to trophy hunting. I show that adult males are the most susceptible cohort to hunting (sub-adults least susceptible). I then take the incident rates from ecological and anthropogenic models and create a theoretical harvest composition using population parameters of protected leopards. My third data chapter departs from hunting susceptibility and examines determinants of leopard trophy package price across Africa. I show that factors such as trophy quality, outfitter leopard hunting reputation and hunt success have little impact on price determination. Instead, overall outfitter reputation and the number of charismatic species in a package are positively correlated with price. These results have important consequences on several sustainable leopard hunting schemes proposed in the literature.

Conservation and behavior of Africa's "Big Five"

Article

Full-text available

May 2014

We examine the conservation status of Africa's " Big Five " : lion, leopard, buffalo, black and white rhinoceros and elephant, and the role of behavioral knowledge in their conservation. Efforts to conserve these flagship species consist of in situ conservation, captive breeding and reintroductions. With a few exceptions, we find limited evidence that knowledge of behavior informs conservation programs targeted at these species. For management in the wild, knowledge of infanticide and ranging can provide guidelines for realistic hunting quotas and corridors between protected areas, respectively. For ex situ and reintroduction programs, behavioral knowledge is chiefly focused on improved animal husbandry. Despite a formidable understanding of these species' behavior, the practicalities of using such knowledge may be diminished because exploitation of these species is so forceful and the bulk of efforts aimed at conserving these species (and indeed most other African species) are primarily in situ where behaviorally driven interventions are limited. Our comparative findings suggest that behavior has been of rather narrow use in the conservation of these flagship species [Current Zoology 60 (4): 486–499, 2014].

Panthera pardus

Chapter

Full-text available

Jan 2013

The African Leopard: Ecology and Behavior of a Solitary Felid

Article

Full-text available

Nov 1994

Reproductive success of female leopards Panthera pardus: The importance of top-down processes

Article

Full-text available

Jun 2013
MAMMAL REV

1.Long-term studies on large felids are rare and yet they yield data essential to understanding the behaviour of species and the factors that facilitate their conservation. 2.We used the most extensive data set so far compiled on leopards Panthera pardus to establish baseline reproductive parameters for females and to determine the demographic and environmental factors that affect their lifetime reproductive success. 3.We used comprehensive sightings reports and photographs from ecotourism lodges in the Sabi Sand Game Reserve, South Africa, to reconstruct life histories for 44 female leopards that gave birth to 172 litters over a 32-year period. 4.Leopards appeared to exhibit a birth pulse; most litters were born in the wet season, particularly in December. Mean age at first parturition (n = 26, mean ± standard error = 46 ± 2 months, range = 33–62) was older than previously recorded, possibly due to elevated intraspecific competition. Average litter size was 1.9 ± 0.1 (n = 140, range = 1–3) and declined with maternal age. Age of litters at independence (n = 52, 19 ± 1 months, range = 9–31) was inversely related to prey abundance but did not affect the likelihood of recruitment of offspring. Interbirth intervals differed following successful litters (in which at least one cub survived to independence; n = 55, 25 ± 1 months, range = 14–39) and unsuccessful litters (n = 46, 11 ± 1 months, range = 4–36), as did the time taken to replace litters. 5.Variation in lifetime reproductive success was influenced mainly by differences in cub survival, which was related to maternal age and vulnerability to infanticide. Cub survival (37%) declined as females got older, perhaps because mothers relinquished portions of their home ranges to philopatric daughters. Male leopards were responsible for many (40%) cub deaths and females appeared to adopt severalstrategies to counter the risk of infanticide, including paternity confusion and displaying a period of reduced fertility immediately after a resident male was replaced. 6.Our results suggest that the reproductive success of female leopards is regulated primarily by top-down processes. This should be taken into account in management decisions, particularly when managers are considering the implementation of invasive activities such as legal trophy hunting.

A Case of Offspring Adoption in Leopards, Panthera pardus

Article

Full-text available

Apr 2012
S AFR J WILDL RES

We document the first reported instance of offspring adoption in a wild leopard (Panthera pardus) population and discuss the potential fitness benefits accrued by the biological and foster mothers. A 15-year-old female leopard adopted the 7-month-old male cub of her 9-year-old daughter and successfully raised him to independence. The behaviour was presumably motivated by kin selection as no reciprocal support was gained by the adoptive mother, she did not benefit from additional parental experience, and it was unlikely to be a case of reproductive error.

Factors affecting leopard (Panthera pardus) spatial ecology, with particular reference to Namibian farmlands

Article

Full-text available

Nov 2004
S AFR J WILDL RES

Understanding spatial ecology is fundamental to effectively managing large, wide-ranging carnivores such as the leopard (Panthera pardus). While numerous studies have been conducted on leopards within protected areas, more information regarding leopard ecology is needed outside such areas for effective conservation. This study examined the spatial ecology of leopards living on commercial Namibian farmlands, and assessed information from other studies to investigate which factors appeared to influence leopard range size and density. Home range sizes were particularly large in Namibia, with high range overlap, and neither sex exhibited exclusive home range use. There were no significant differences in range size between males and females, or between wet and dry seasons for either sex. Rainfall did not directly affect range size, but exerted an influence via prey biomass. Leopard density was positively correlated with prey biomass and negatively related to range size. Leopards showed marked variation in range size and land tenure systems between studies, reflecting their remarkable ecological flexibility. Nevertheless, large home range sizes and low population densities mean that leopards require large, contiguous tracts of suitable habitat, and that more conservation efforts must be extended beyond protected areas to ensure the long-term viability of leopard populations in such areas.

Improving data analysis in herpetology: using Akaike's Information Criterion (AIC) to assess the strength of biological hypotheses

Article

Full-text available

Mar 2006

Marc J. Mazerolle

In ecology, researchers frequently use observational studies to explain a given pattern, such as the number of individuals in a habitat patch, with a large number of explanatory (i.e., independent) variables. To elucidate such relationships, ecologists have long relied on hypothesis testing to include or exclude variables in regression models, although the conclusions often depend on the approach used (e.g., forward, backward, stepwise selection). Though better tools have surfaced in the mid 1970's, they are still underutilized in certain fields, particularly in herpetology. This is the case of the Akaike information criterion (AIC) which is remarkably superior in model selection (i.e., variable selection) than hypothesis-based approaches. It is simple to compute and easy to understand, but more importantly, for a given data set, it provides a measure of the strength of evidence for each model that represents a plausible biological hypothesis relative to the entire set of models considered. Using this approach, one can then compute a weighted average of the estimate and standard error for any given variable of interest across all the models considered. This procedure, termed model-averaging or multimodel inference, yields precise and robust estimates. In this paper, I illustrate the use of the AIC in model selection and inference, as well as the interpretation of results analysed in this framework with two real herpetological data sets. The AIC and measures derived from it is should be routinely adopted by herpetologists.

Wolf, Canis lupus, Pup Mortality: Interspecific Predation or Non-Parental Infanticide?

Article

Full-text available

Apr 2011
Can Field Nat

A breeding male Gray Wolf, Canis lupus, equipped with a GPS collar was documented going to the den site of another Gray Wolf pack. This trip was coincident with an attack on the den of the other pack and the occurrence of a dead and partially con - sumed Gray Wolf pup at the same location. We present two possible explanations-interspecific predation and non-parental infanticide-to account for this observation. Because the Gray Wolf with the GPS collar and his mate were first-time breeders and were attempting to establish a territory space of their own, we speculate that, based on the available evidence, this observation most likely represents a case of non-parental infanticide that fits the predictions of the resource competition hypothesis.

Sexually selected infanticide in grizzly bears: The effects of hunting on cub survival

Article

Full-text available

Jan 2009

Bruce Mclellan

Sexually selected infanticide (SSI) has been documented in some species with a mating system in which males have almost exclusive breeding rights with 1 or more females. When the dominant male is removed, the new male kills the offspring sired by the previous male to enable the mother to be bred earlier. It has been suggested that this immigrant male hypothesis of SSI operates in grizzly bears (Ursus arctos) and that removing dominant males by hunting results in high cub mortality due to killing by immigrant males, or in low reproductive rates because of a female counterstrategy of using suboptimal habitat to avoid potentially infanticidal immigrant males. I tested 2 predictions of the immigrant male hypothesis in a hunted area adjacent to protected areas with high densities of grizzly bears that could supply immigrant males. These predictions were not supported. Over 25 years, 134 grizzly bears were captured: most of the 77 male and 57 female grizzly bears were ≤3 years of age when first captured (54.5% and 52.6%, respectively), and 22.1% of the males and 19.3% of the females were 4–6 years of age when first captured. Similarities of these sex ratios suggest that there was not a substantially greater influx of subadult males than females into the hunted area. Cub survival to the end of the breeding season was high (0.93 or 0.95; n = 87), as was annual cub survival (0.85, n = 81); 15% of the 39 litters monitored for an entire year were completely lost. Yearling survival was 0.95 to the end of the breeding season, when SSI should cease. These results do not support the immigrant male hypothesis of SSI but suggest that grizzly bears either do not exhibit SSI, or that SSI exists in a different form. I propose a second hypothesis of how SSI may operate in bears. This mate recognition hypothesis of SSI is that males of any age may, if they are able, kill cubs that they believe they did not sire the previous year and try to mate with the mother. I use a simulation model to evaluate factors that may influence the existence and likely form of SSI in bears. Results of this study suggest that killing some adult males under a sustainable management regime does not decrease cub survival.

Life-history variables of an atypical mustelid, the honey badger Mellivora capensis

Article

Full-text available

Dec 2004
J ZOOL

The honey badger, or ratel, Mellivora capensis has not been well studied and data on life-history variables have previously been incomplete and contradictory. Here we present data on life-history variables that were collected from visual observations as part of the first intensive study of free-living honey badgers (25 radio-marked individuals) and we make comparisons with other similarly sized mustelids (5–25 kg). The honey badger is a non-social species and only the mother rears the young. The data do not support delayed implantation as gestation was a maximum of 50–70 days with the unusually small litter size of one cub. The long time to independence of both male and female cubs (12–16 months) resulted in birth intervals longer than 12 months with no distinct breeding season. Overall the honey badger appears to have a more K-selected life history compared to other species within the Mustelidae.

The role of intraspecific predation in the survival of juvenile wolverines Gulo gulo

Article

Full-text available

Mar 2003
WILDLIFE BIOL

Wolverine Gulo gulo populations have a low reproductive potential and are thus relatively sensitive to changes in survival rates. Consequently, knowledge about survival and mortality causes in juvenile wolverines is important for a sound management of the species. We estimated survival rates for juvenile wolverines and evaluated the relative importance of intraspecific predation compared to other mortality causes in northern Scandinavia during 1993-2001. We monitored 80 radio-marked juvenile wolverines from May to February. Intraspecific predation was the most important cause of juvenile mortality and occurred during two periods. First, seven juveniles were killed in May-June when still altricial, i.e. infanticide. Second, four juvenile females were killed by conspecifics outside their mothers' territories after independence in August-September. The survival rate of radio-marked juveniles during May-February was 0.68. There was a strong tendency for survival to be lower during the summer when juveniles were altricial, than after they became independent. The estimates of survival rates and mortality causes provided by this study are important for the understanding of wolverine population dynamics. Currently, our data are too weak to suggest an explicit explanation for infanticide in spring/early summer. Still, in the light of the available information on wolverine life history and infanticide patterns in other species, we suggest two, not mutually exclusive, hypotheses to consider for further investigation: 1) males kill non-related juveniles to increase their reproductive success, and 2) females kill non-related juveniles to reduce competition for resources. In addition, attention should be given to the alternative hypothesis that infanticide in wolverines is non-adaptive. Finally, we suggest that independent juvenile females were killed by resident females in territorial defence.

Infant Killing in Primates: A Review of Observed Cases with Specific Reference to the Sexual Selection Hypothesis

Article

Full-text available

Oct 2009
AM ANTHROPOL

Discussion of infant killing in free-ranging primates has focused on the sexual selection hypothesis developed by Hrdy during the mid-1970s. This hypothesis suggests that infant killing is a form of sexual competition whereby an infanticidal male gains a reproductive advantage by selectively killing the offspring of his male rivals. Despite criticisms that the evidence in support of the hypothesis is distorted by misinterpretation of data and observer bias, the sexual selection hypothesis, bolstered in part by additional reports of infanticide in a variety of specks, has become entrenched as the primary explanatory hypothesis for primate infanticide. However, the majority of reliably documented instances of infanticide in primates come from a very small number of species, and a careful examination of the specific context of each of these episodes fails to support the interpretation of infanticide as a primatewide adaptive complex. Most importantly, the atmosphere of generalized inter- and intrasexual aggression that surrounds the majority of infant killings obscures the evolutionary significance of this behavior.

Large predators and their prey in a southern African savanna: a predator's size determines its prey size range

Article

Full-text available

Apr 2004
J ANIM ECOL

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.

Estimating effects of adult male mortality on grizzly bear population growth and persistence using matrix models

Article

Full-text available

Apr 2001
BIOL CONSERV

We radio monitored a hunted, sexually segregated grizzly bear (Ursus arctos) population and an unhunted, unsegregated population for demographics and constructed a stage- and age-classified matrix model to test for the effects of adult male mortality and resulting sexual segregation on population growth and persistence. Population parameters in the model were adult female survival, subadult female survival, offspring survival, probability of litter sizes, and probability of unsuccessful pregnancy. The last three parameters were affected by adult male mortality and segregation, the others were not. We compared population growth with and without effects of hunting by holding adult female and subadult female survival constant and by using hunted and unhunted values for offspring survival, litter size, and pregnancy. Population growth (Lambda) showed the greatest elasticity for adult survival, subadult survival, offspring survival, litter size, and unsuccessful pregnancy, in that order. This corresponds with observed anti-infanticide tactics (sexual segregation) by adult females to maximize their fitness. The hunted population decreased at a rate of 0.99 whereas the simulated, unhunted population increased at a rate of 1.05. The hunted population was much more susceptible to population extinction. Under demographic stochasticity mean time to extinction was 32 years in the hunted population and 110 years in the unhunted population. Under environmental stochasicity mean time to extinction was 21 years in the hunted population and 43 years in the unhunted population. We suggest that sexual segregation caused by hunting resident adult males can result in population decline and can even contribute to rapid population extinctions when numbers are small.

Infanticide among Animals: A Review, Classification, and Examination of the Implications for the Reproductive Strategies of Females

Article

Full-text available

Oct 1979

Sarah Blaffer Hrdy

Infanticide among animals is a widespread phenomenon with no unitary explanation. Although the detrimental outcome for the infant is fairly constant, individuals responsible for infanticide may or may not benefit, and when they gain in fitness there may be considerable variation in how they gain. Sources of increased fitness from infanticide include: (1) exploitation of the infant as a resource, (2) elimination of a competitor for resources, (3) increased maternal survival or lifetime reproductive success for either mother or father by elimination of an ill-timed, handicapped, or supernumerary infant, and, finally, (4) increased access for individuals of one sex for reproductive investment by the other sex at the expense of same-sex competitors. Predicted attributes of the perpetrators (such as sex and degree of relatedness to the infant), attributes of the victim (i.e., age and vulnerability), as well as schedule of gain, vary for each class. Under some circumstances, individuals commit infanticide which does not result in any prospect for gain; such instances are considered nonadaptive or “pathological.” In those cases where infanticide does on the average increase fitness, selection pressures favoring it have arisen as a result of the extensive and time-consuming investment involved in production of young, and the extreme vulnerability that characterizes infancy in many animals.

Impact of conservation interventions on the dynamics and persistence of a persecuted leopard (Panthera pardus) population

Article

Full-text available

Nov 2009
BIOL CONSERV

There is an extraordinary assortment of technical approaches to conserving carnivore populations, but the effectiveness of conservation activities is rarely evaluated. Accordingly, we initiated a study to assess the impact of several conservation interventions on the dynamics and persistence of a leopard (Panthera pardus) population in Phinda Private Game Reserve, South Africa. These included revisions of the statutory systems that regulate problem animal control and trophy hunting, and we instituted a program intended to reduce human–leopard conflict in the region. We compared demographic rates of radiocollared leopards from two sampling periods: a pre-treatment period prior to intervention, and a treatment period after intervention. The average annual mortality rate of the population decreased from 0.401 ± 0.070 to 0.134 ± 0.016, with fewer leopards killed by humans and in intraspecific clashes after intervention. The overall reproductive output of the population increased in the treatment period, although annual cub production was higher in the pre-treatment period. This was mainly due to larger litter sizes prior to intervention, which may have been a strategy used by female leopards to offset high levels of infanticide. Results from camera-trap surveys and a Leslie-matrix model indicated an increase in annual population growth rate (λ) of 14–16% after the implementation of conservation measures. Our findings highlight the importance of addressing both the numerical and functional components of population dynamics when managing large carnivores exposed to hunting or persecution.

Maternal rank is not correlated with cub survival in the spotted hyena, Crocuta crocuta

Article

Full-text available

Jan 2005

Paula White

Reproductive success in female spotted hyenas, Crocuta crocuta, is positively correlated with social rank. High-ranking females are known to produce more offspring, but the effects of maternal rank on early cub survivorship have not been investigated. Cub mortality was examined over a 4-year period in one clan of wild-living spotted hyenas in Kenya. Data were obtained for 100 cubs in 63 litters produced by 27 adult females. Survivorship of cubs from birth through their first year was examined as a function of litter size, sex of cubs, and maternal rank. Overall, cub mortality was high (61%). Contrary to expectation, singleton cubs did not survive better than twins, and there was no difference in survivorship between female and male cubs. High-ranking mothers were not more successful at raising twins or daughters than were low-ranking mothers. There was no correlation between cub mortality and maternal rank. Peaks in cub mortality coincided with life stage events, including mean age of arrival at a communal den, and age at which cubs began visiting kills. Documented causes of mortality included intraclan infanticide, disease, orphaning, predation by lions, and a mechanism of filial infanticide that has not been previously described in this species: selective litter reduction by mothers via partial litter abandonment. No instances of facultative or obligate siblicide were detected. During this study, association between rank and number of cubs surviving to 1 year of age appeared to be due to differences in reproductive output and not differential survival of cubs within their first year. Copyright 2005.

Sport Hunting, Predator Control and Conservation of Large Carnivores

Article

Full-text available

Feb 2009
PLOS ONE

Sport hunting has provided important economic incentives for conserving large predators since the early 1970's, but wildlife managers also face substantial pressure to reduce depredation. Sport hunting is an inherently risky strategy for controlling predators as carnivore populations are difficult to monitor and some species show a propensity for infanticide that is exacerbated by removing adult males. Simulation models predict population declines from even moderate levels of hunting in infanticidal species, and harvest data suggest that African countries and U.S. states with the highest intensity of sport hunting have shown the steepest population declines in African lions and cougars over the past 25 yrs. Similar effects in African leopards may have been masked by mesopredator release owing to declines in sympatric lion populations, whereas there is no evidence of overhunting in non-infanticidal populations of American black bears. Effective conservation of these animals will require new harvest strategies and improved monitoring to counter demands for predator control by livestock producers and local communities.

DNA analyses support the hypothesis that infanticide is adaptive in langur monkeys

Article

Full-text available

Jun 1999

Although the killing of dependent infants by adult males is a widespread phenomenon among primates, its causes and consequences still remain hotly debated. According to the sexual selection hypothesis, infanticidal males will gain a reproductive advantage provided that only unrelated infants are killed and that the males increase their chances of siring the next infants. Alternatively, the social pathology hypothesis interprets infanticide as a result of crowded living conditions and, thus, as not providing any advantage. Based on DNA analyses of wild Hanuman langurs (Presbytis entellus) we present the first evidence that male attackers were not related to their infant victims. Furthermore, in all cases the presumed killers were the likely fathers of the subsequent infants. Our data, therefore, strongly support the sexual selection hypothesis interpreting infanticide as an evolved, adaptive male reproductive tactic.

Paternity confusion and the ovarian cycles of female primates

Chapter

Nov 2000

Male primates, carnivores and rodents sometimes kill infants that they did not sire. Infanticide by males is a relatively common phenomenon in these groups, but tends to be rare in any given species. Is this behavior pathological or accidental, or does it reflect a conditional reproductive strategy for males in certain circumstances? In this book, case studies and reviews confirm the adaptive nature of infanticide in males in primates, and help to predict which species should be vulnerable to it. Much of the book is devoted to exploring the evolutionary consequences of the threat of infanticide by males for social and reproductive behavior and physiology. Written for graduate students and researchers in animal behavior, behavioral ecology, biological anthropology and social psychology, this book shows that social systems are shaped not only by ecological pressures, but also social pressures such as infanticide risk.

Vulnerability to infanticide by males: patterns among mammals

Chapter

Nov 2000

Carel P van Schaik

Infanticide by male primates: the sexual selection hypothesis revisited

Chapter

Nov 2000

Carel P van Schaik

Infanticide by female mammals: implications for the evolution of social systems

Chapter

Nov 2000

Leslie J. Digby

Infanticide in lions: Conse quences and counterstrategies

Article

Jan 1994

Infanticide in carnivores

Article

Rough rookeries

Article

Jan 1994
NAT HIST

F. Bruemmer

Infanticide: Comparative and Evolutionary Perspectives

Article

Jul 1985

Copulatory parameters and reproductive success of wild leopards in South Africa

Article

Oct 2010

Leopards (Panthera pardus) are a poorly understood, solitary felid, and additional study could provide novel insights into both evolution and conservation management. We studied the reproductive biology of 7 adult female and 2 adult male leopards on Karongwe, South Africa, from 1999 to 2005. We intensively researched copulatory biology from 2001 to 2003, during which we observed 19 consortships and 4,855 copulations (1,809 copulations visually) during 2,449 h of following consort pairs. Leopards copulated on average 4 times per hour, with an average of 256 copulations per consortship. Conception rate was low, resulting, on average, after 2.3 consortships (SE = 0.4 consortships). All reproductive parameters except gestation length were shorter than those in published literature, which we suspect reflected a facultative response to superabundant resources. Although females produced the expected 1.6 cubs per year, lifetime reproductive rates on Karongwe Reserve were approximately half that reported elsewhere due to lower female survival resulting from intraspecific factors. These results offer encouragement for founding new populations of endangered felids in areas of high prey availability and resource abundance, provided factors affecting population regulation can be managed.

Model Selection and Multimodel Inference: A Practical Information-Theoretic Approach

Book

Jan 2002

Adaptations of Female Lions to Infanticide by Incoming Males

Article

May 1983

Female Panthera leo with cubs show various direct responses to immigrating males, including defense of their cubs or avoidance of the new males. Despite these responses, male replacement in the females' pride results in considerable cub mortality. Those females that remain in the pride and mate with the new males show low fertility in the first few months after a takeover of their pride. At the same time, however, females show heightened sexual activity, being more active in initiating copulations and seeking a greater number of mating partners. These 2 factors appear to elicit competition between male coalitions for control of the pride, with the result that larger coalitions eventually become resident. This is adaptive because a female needs protection from male harassment of her cubs for >2 yr in order to rear her cubs successfully, and only large male coalitions are likely to remain in a pride for >2 yr. A simple model specifies one set of conditions under which a female will improve her lifetime reproductive success by showing temporary periods of infertility, but attracting a larger coalition. -Authors

Infant killing as an evolutionary strategy: Reality or myth?

Article

Jun 2005
EVOL ANTHROPOL

Paternity confusion and the ovarian cycles of female primates

Article

Jan 2000

Why leopards commit infanticide

Abstract

No full-text available