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The Amboseli Elephants: A Long-term Perspective on a Long-lived Mammal by C. J. Moss; H. Croze; P. C. Lee
Abstract
C. J. Moss, H. Croze, P. C. Lee (eds.). 2011. The Amboseli Elephants: A Long-term Perspective on a Long-lived Mammal. University of Chicago Press, Chicago, Illinois, 383 pp. ISBN-13 978-0-226-54223-2 and ISBN-10 0-226-54223-8, price (hardbound), $65.00.
A 38-year program of research on a single population, the Amboseli Elephant Research Project, stands as a pinnacle example of mammalogy for its length and depth of investigation. This study, widely known through the scientific and popular writing of Cynthia Moss and Joyce Poole, is now put into full scientific context in this edited multiauthor volume that was 12 years in the making, or as the authors point out, “the gestation period of 5–6 elephant calves.”
What the authors have achieved is not just a reference on the Amboseli population, but a compendium of biological, ecological, and natural history knowledge on elephants. By comparison, all the other great books on elephant behavior read more like travelogues or biographies. Be warned, readers looking for the common coffee table book with large glossy color photos and field anecdotes will be sorely disappointed. Appealingly, this book instead focuses on providing a well-organized overview of the Amboseli system and the elephants within it by summarizing previously published research findings (with updated information), as well as novel information not published in the peer-reviewed literature during this long-term project.
The book is organized into 5 parts. In Part 1, the editors set the background for their subsequent detailed sections on elephant behavior. Harvey Croze and Keith Lindsay provide a background chapter devoted to the biotic and abiotic conditions of Amboseli and how those conditions changed over time. Kadzo Kangwana and Christine Brown-Nunez provide an intriguing and detailed account of how Maasai communities surrounding the park are shifting toward a more sedentary agricultural lifestyle that is incorporated into the commercial economy. Treated objectively in Part 1, the increasing importance of human land use and interactions with elephants is a recurrent theme throughout the book, and is revisited from the perspective of Amboseli Elephant Research Project proponents in …
... Environmental factors also influence elephant conception rates. A further consequence of these impacts on mortality and conception may be the appearance of population pulses, with brief, exceptional rates of population increase if females become synchronized in their conceptions and births (Lee et al. 2011). ...
... These herds may be accompanied by adult males, which are assumed to be temporary visitors. The relatedness of the adult females and immatures in a female herd is unknown, but it is assumed that the herd is a family unit sensu Moss et al. (2011). The capture of numerous elephants in entire female herds during 1993 provided a representative sample of the population of females and immature males, from which the immediate post-drought sex and age structure of the female herds could be estimated. ...
... In common with the Gonarezhou results, studies elsewhere find high drought mortality among immature elephants. In Amboseli, Kenya, extreme, prolonged droughts during the 1970s and 1980s resulted in exceptionally high calf mortality of between 40 and 60% during the first two years of life, while average non-drought calf mortality was ~12% (Lee et al. 2011(Lee et al. , 2022. In Tarangire, Tanzania, drought mortality during 1993 among animals aged <8 years was 20%, with the majority of these deaths occurring amongst dependent calves (Foley et al. 2008). ...
Hundreds of elephants died during a severe drought in Gonarezhou National Park (Gonarezhou) in south-east Zimbabwe during 1992. The following year, entire female herds comprising 670 female and juvenile elephants were captured and translocated elsewhere. Sex-specific von Bertalanffy growth functions for shoulder height against age for elephants culled in Gonarezhou a decade earlier allowed each of 667 elephants captured during 1993 to be aged based on shoulder height. The captured elephants provided a representative sample of the age and sex structure of the population one year after the drought. Immediately after the drought, the age structure was determined by deducting one year from each elephant’s age at capture and compared with that of elephant herds culled in Gonarezhou during 1972-1987. Adult females formed a high proportion (45%) of the individuals in female herds immediately after the 1992 drought, implying that there was high mortality of non-adults during the drought. There were relatively few surviving individuals in the 0-4-year age class, suggesting that mortality was greatest amongst the youngest individuals. When non-adults of all ages were considered, there were fewer males than females amongst the drought survivors, suggesting that the males experienced greater mortality than females. Significant mortality of weaned elephant calves during droughts is uncommon; and the high mortality of non-adults in Gonarezhou during 1992 highlights the particular severity of the drought.
... Elephants live in large, fission-fusion matriarchal family groups with multimodal sensory perception and communication, and are capable of problem-solving, targeted helping, and empathy [9•,17], but we know this largely due to long-term ethological studies (e.g. [18]). The paucity of experimental data is likely due both to the difficulty of testing elephants in captivity -there are no university labs in which elephants can, or should be transported -and in the wild, where rapidly decreasing numbers and increasing conflict with humans make it difficult to establish controlled research programs [19••]. ...
... Long-term field sites have focused on the behavioral ecology of African (savanna, Loxodonta africana - [18,22]; forest, L. cyclotis -[23]) and Asian elephants [24,25] for decades, providing considerable evidence for the complexity of elephant sociality across species. Nonetheless, relatively few studies have focused on the cognitive mechanisms underlying elephant behavior [9•,17]. ...
... Much of what we do know about elephant cognition is scattered across multiple cognitive themes, suggesting the field is new and studies often designed opportunistically. As elephants live in complex fission-fusion social environments, where they must keep track of social relationships with many partners [18,34], elephant social cognition is likely the area of research that has received the most attention. A study with wild African elephants, for instance, provided evidence that they could recognize up to 30 individuals based on odor cues and remember their relative locations [35]. ...
While researchers interested in the evolution of human intelligence have traditionally focused on the psychology of other primates, a growing field aims to understand how similar cognitive abilities emerge in evolutionarily distant taxa. Here, we briefly review what we know, and why we do not know more, about the ‘mind’ of one such animal — the elephant — as well as its relevance to understanding convergent cognitive evolution across species. We also discuss the importance of studying animals such as elephants in the wild to better identify expressions of cognitive flexibility in human-impacted environments. Finally, as researchers invested in the study of an endangered species, we emphasize the need to contribute to the management of conservation-related problems from novel, cognitive perspectives.
... This compound is a confirmed pheromone in bark beetles and European rabbits and a discussion point. Bold semiochemical in elephants , 2012, * confirmed semiochemical in mammals . **of mammalian origin tetramethylphenol. ...
... The female elephants had ketones as a major compound class, but not Octadien-4-one. Bold semiochemical in elephants , 2012, * confirmed semiochemical in mammals . **of mammalian origin ). ...
... To the best of our knowledge this compound has not been previously reported in elephants. , 2012, *confirmed semiochemical in mammals . **of mammalian origin ...
As an endangered mammal, novel research into the African elephant’s ethochemistry will assist ethologists, conservation biologists and wildlife managers in understanding odour signals in elephant exudates, and how they impact elephant behaviour in captivity and in the wild. Analytical methods combining genetics, statistics with SPME GC_MS and innovative metabolomics visualisation software are a useful first step in unlocking odours salient to elephant reproduction, breeding and behaviour. Mammals, such as the African elephant, which live in sophisticated, fission-fusion, social systems marked by linear dominance hierarchies and ritualized greeting ceremonies, require an effective means of communication in order to maintain social cohesion. A number of acoustic, olfactory and visual signals have been described. Within a group context, individuals need to discriminate between members of their group and foreign conspecifics in order to avoid inbreeding and to identify recipients of nepotistic behaviour. Such olfactory group/herd/clan/colony identity signals have been described in a number of mammals such as beavers, bats, naked mole rats, rabbits, fur seals, lemurs and hyena but are lacking in the iconic African elephant. It is to date not clear what fixed and variable information is encoded in African elephant urine, temporal gland secretions (TGS), genital and buccal secretions, and whether an olfactory signal for herd membership exists, although scientists have long expected this to be the case. Specifically, African elephant TGS, buccal and genital secretions in adult females have not been described in a free-ranging population. The overall objective of this research was to augment scientific understanding of African elephant olfactory behaviour in a multi-disciplinary way, combining behavioural observation and experimental trials of African elephants in sanctuaries in South Africa, with genetic and chemical data sampled from a free-ranging African elephant population during a translocation event in Malawi. The research first assesses olfactory acuity and scent discrimination ability in African elephants through novel behavioural bioassays. Subsequently, this study examines whether chemical signals in urine, TGS, buccal and genital secretions encode for age, sex and identity, and explores whether odour is correlated with genetic relatedness. For the first time, the chemistry in TGS, buccal and genital secretions is characterised in wild African elephant adult females (n=40). Elephants were found to be highly adept at scent-discriminating between humans, and scent- tracking a target human across various substrates, including distractor trails. Results suggest that elephants may utilise olfaction to discriminate between individual conspecifics. This was tested using behavioural bioassays, which concluded that African elephants can discriminate between unfamiliar and familiar conspecifics from both urine and dung. Urine elicited the most interest, and was used for further detailed analysis using the comprehensive metabolomics tool XCMS online. TGS, buccal and genital secretions from wild-sampled elephants (n=113) were found to encode individual identity in African elephants. TGS and buccal secretions encoded for age, and TGS and genital secretions tended towards significance for sex. Genetic relatedness was not correlated with odour in TGS, buccal and genital secretions at the herd level. However in all three odours, Similarity Percentage Analysis (SIMPER) identified “herd” as a highly significant factor in explaining chemical differences between herds. This suggests that group odour in African elephants is not correlated to genetic relatedness at the population, herd and individual level, and allows for the possibility that bacteria may be involved in group odour. The biomarkers alkan-2-ones and alkan-2-ols previously published in association with elephant male urinary microbial communities, were identified in adult female buccal and labial secretions. SIMPER analyses further extracted a number of short-chain fatty acids significant to chemical differences between groups (notably acetic acid, pentanoic acid, hexanoic acid, decanoic acid, dodecanoic acid and tetradecanoic acid). These and other compounds have been identified in similar studies as key volatile compounds from bacterial fermentation in clan-living hyenas and colonially-living meerkats, further supporting this possibility. The frequent affiliative social behaviour of African elephants is posited as a likely mechanism for bacterial transmission. Conservation objectives can be supported by an improved understanding of how chemical communication in social mammals like elephants influences mate choice, establishing social relationships, courting, mating and the use of scent for establishing territories. In African elephants, an improved understanding of elephant semiochemistry and eliciting behaviour could shed light on scent manipulation for elephant translocation and reintroductions, captive breeding, welfare and enrichment protocols, human elephant conflict (HEC), elephant reintroductions, social behaviour and habitat selection.
... We used these vital rates to calculate a baseline population growth rate for the Mashi elephant population. Female elephant vital rates were taken from a dataset derived from long-term observations of elephants in East Africa (Moss et al., 2011). Though this dataset was produced in a different region of Africa than our study site, Moss et al.'s (2011) study provides reliable long-term demographic data on a population of savannah elephants experiencing little immigration, emigration, or poaching, which is necessary for calculating the population growth that Mashi contributes to the regional elephant population (See Supplemental Information for further details). ...
... As there does not appear to be any sex ratio bias in savannah elephant calves, we assumed that the production of female and male calves is equal, as males are the only sex that is reportedly hunted in Mashi (Moss, 2001). As only adult elephants are hunted, we used aggregated demographic data provided by Moss et al. (2011) to calculate the probability of survival to 15 years for male calves and scaled the production of male calves by this amount to estimate the 10-year adult male production (Table S2). We used this production as the sustainable annual offtake and calculated the benefits of the elephant harvest by multiplying this offtake by the conservancy's per-elephant fee (N$ 180,000/US$ 13,100 per-elephant) plus the value of the meat produced by each elephant (N$ 24/US$ 1.75 per-kg [NACSO, 2018] and 1,000 kg meat/elephant reported by the Mashi conservancy chairperson) for a total value of US$ 14,900 (N$ 204,000) per-elephant. ...
... These findings are based on a conservative approach: our calculation for sustainable hunting offtake in Mashi utilizes a greater elephant density than the conservancy's reported elephant density and also assumes an optimistic population growth rate. As our estimated growth rate was derived from a population of elephants that had little mortality from poaching or hunting, it is almost certainly higher than what is occurring in the Zambezi region of Namibia (Moss et al., 2011). In fact, the time series of elephant surveys used by Robson et al. (2017) showed no significant trend in elephant population size in the Zambezi region from 1989 to 2013. ...
The Kazavango‐Zambezi Transfrontier Conservation Area is home to the largest remaining elephant population in Africa but is also the site of high levels of human‐elephant conflict through crop depredation. Offsetting the costs of coexisting with elephants in this area is critical to incentivizing elephant conservation within community‐based conservation (CBC) areas, and trophy hunting has long been touted as a method for generating revenue for communities from wildlife. However, the idea that sustainable elephant hunting can offset the costs of crop depredation remains largely untested. We combined household survey data, financial records, and elephant population data to compare the potential benefits of sustainable hunting with the costs of crop depredation in a CBC area in northeastern Namibia. We determined that sustainable trophy hunting only returns ~30% of the value of crops lost to the community and cannot alone offset the current costs of coexistence with elephants. As core institutions supporting the practice of conservation, CBC efforts must promote community management capacity to combine multiple wildlife‐based income streams and build partnerships at multiple scales of governance to address the challenges of elephant management.
... One in four of the calf deaths are due to maternal agalactia (lack of milk) and/or general weakness of the new-born calf [10]. Similarly, on average 19% of calves die before five years of age in wild populations of African elephants (Loxodonta africana) [11] and a portion of the calf deaths are due to mothers struggling to meet the lactation demands. During dry years mothers are unable to sustain milk production at a level that meets the metabolic requirements of their larger sons, and as result male calves are more likely to die [12]. ...
... During dry years mothers are unable to sustain milk production at a level that meets the metabolic requirements of their larger sons, and as result male calves are more likely to die [12]. Furthermore, during poor seasons or years, mothers of calves under two years of age are at greater risk of mortality as a consequence of lactation costs [11,13]. In zoos, the calf mortalities are high, especially in Asian elephants (on average 30% during the first year), and one of the most important reasons is rejection of the calf by the mother, resulting in a need for human intervention to supplementally feed the calves [14]. ...
... In zoos, the calf mortalities are high, especially in Asian elephants (on average 30% during the first year), and one of the most important reasons is rejection of the calf by the mother, resulting in a need for human intervention to supplementally feed the calves [14]. Many of the reasons underlying such high calf mortality are relatively well studied in elephants [9][10][11][15][16][17][18], but milk composition has gained less attention even though it may be an important factor underlying mortality. Such information, particularly from animals managed in their natural habitat, could have major potential to bring about important advances for improving calf survival and maternal well-being in diverse elephant populations. ...
The nutritional content of milk from free-living Asian elephants has not previously been reported, despite being vital for better management of captive populations. This study analyzed both milk composition and consumed plant species of Asian elephants managed in their natural environment in Myanmar. Longitudinal samples (n = 36) were obtained during both the wet and the dry season from six mature females in mid to late lactation in 2016 and 2017. Milk composition averaged 82.44% water, with 17.56% total solids containing 5.23% protein, 15.10% fat, 0.87% ash, and 0.18 µg/mL vitamin E. Solids and protein increased with lactation month. Total protein in milk was higher during the wet vs. the dry season. Observed factors linked with maternal (age, parity, size and origin) and calf traits (sex) had significant associations with milk nutrient levels. Primary forages consumed contained moderate protein and fiber. Higher dietary protein during the wet season (11–25%) compared to the dry season (6–19%) may be linked with increased milk protein observed. Our results call for further field studies of milk and diet composition, over entire seasons/lactation periods, and across maternal and calf traits, to improve feeding management, with an overall goal of maximized health and survival.
... non-sharable) types of care, such as allonursing, transfers of food, information and social status, but also 'non-depreciable', or at least less depreciable, types of care, such as vigilance and protection against predation (Table 2). To the best of our knowledge, only four studies to date have reported that living grandmothers improve the fitness of their descendants in non-human mammal species: MacDonald Pavelka et al. (2002), in an introduced supplementary-fed population of Japanese macaques, Macaca fuscata; Lahdenperä et al. (2016), in semi-captive Asian elephants, Elephas maximus; Moss & Lee (2011), in wild African elephants, Loxodonta africana (see also Foley et al., 2008);and Ward et al. (2009b), in killer whales, Orcinus orca. In contrast, in the typical social mammal, the age and grandparental status of the helper does not appear to provide a specific advantage (Festa-Bianchet, 1991;Packer et al., 1998). ...
... Memory of key resources for times of food or water shortage, experience of predators and anti-predator behaviour (McComb et al., 2001(McComb et al., , 2011, leading to enhanced reproductive output by females whose mother is alive (Moss & Lee, 2011). Social cohesion and transmission of social capital may also be at play. ...
... Offspring performance increases on average with matriarch age, supposedly because only the oldest matriarchs have accumulated the knowledge required to deal with rare events (Foley et al., 2008; reanalysed in Supporting Information, Appendix S1.B). Yet elephant matriarchs continue to breed into old age (Moss & Lee, 2011). ...
Several non-human mammalian species provide grandparental care but remain fertile until death, unlike our species. This might call into question the 'grandmother hypothesis' that the ability to provide grandparental care, associated with an increase in the cost of breeding with age, promote the early cessation of reproduction. Here, we analyse individual longevity records from non-human mammals to determine whether the few species with grandparental care also stand out among mammals in terms of age-specific survival patterns. Indeed, females of species with grandparental care lived on average 43% longer than males (range: 24-61%), compared with 12% in other polygynous species (95% quantile: −8 to 30%), because of low baseline mortality rates and delayed onset of actuarial senescence. We discuss this finding with respect to the 'stopping early' vs. 'living longer' debate. We review the role of the environmental context and of the decrease in offspring performance with maternal age (Lansing effect). We formalize the idea of a continuum of parental-grandparental allocation instead of a discrete switch to grandparental care only. Lastly, we suggest that the evolution of menopause has been driven by different forces in different species. ADDITIONAL KEYWORDS: biodemography-grandparental care-longevity-parental care-senescence.
... Transient dynamics are particularly relevant for savanna elephants. They are large, live long (Lee et al., 2016), have extended and overlapping generations (Wittemyer et al., 2013), have high adult survival rates (e.g., van Aarde et al., 2008;Lee et al., 2011), and low fecundity (late maturity and few offspring) (Lee et al., 2016). These life-history characteristics should buffer populations against disturbances in the highly variable savannas where elephants live. ...
... The relatively small size of MC also does not allow elephants to move to areas less affected by drought, as is the case in larger protected areas (i.e., in Kruger National Park, Abraham et al., 2019). Conception rates are typically lower in dry years (Gough & Kerley, 2006;Rasmussen et al., 2006;Trimble et al., 2009), and an extended drought might also have reduced survival among the younger elephants (Foley et al., 2001(Foley et al., , 2008Young & van Aarde, 2010;Lee et al., 2011;Boult et al., 2018). The harsh conditions during the droughts reduced age-specific survival which also coincided with a lowered number of adult females relative to the nonbreeding cohort in 2020, and collectively destabilized the age structure. ...
Disturbances that change population structure may evoke transient dynamics that can be assessed within a demographic resilience framework. Conservation management interventions are conceptually disturbances that can be evaluated through such a framework to inform management actions and goals. The Main Camp in Addo Elephant National Park in South Africa presents a case study. Here management reduced the size of the elephant (Loxodonta africana) population by ~26%. We compared population growth, modelled trends, constructed life tables and parameterized population projection matrices from data collected before, during and after the interventions. The interventions reduced population size and density, but co‐occurring droughts may have reduced subsequent population growth and stage‐specific survival. Transient dynamics followed the interventions and droughts and were associated with an unstable stage structure. The effect of adult survival on modelled asymptotic growth (its elasticity) was greater than a change in fertility. However, lowered juvenile survival contributed most to changes in transient growth. Management plans for elephant populations should consider the length of transients induced by interventions and environmental disturbances such as droughts. Our approach can benefit the assessment of population responses of elephants to disturbances such as poaching and persistent droughts elsewhere in Africa.
... As male elephants come into musth, they expand their ranges in search of estrus females within highly mobile family groups [7,15,16]. Although female elephants are considered more risk-averse than males and prefer to avoid human-modified landscapes (HMLs) when possible [17,18], females do crop-raid in some systems [19,20], and many family groups utilize travel corridors in unprotected landscapes [21][22][23][24]. ...
... Although female elephants are considered more risk-averse than males and prefer to avoid human-modified landscapes (HMLs) when possible [17,18], females do crop-raid in some systems [19,20], and many family groups utilize travel corridors in unprotected landscapes [21][22][23][24]. Moreover, family groups occupy areas beyond the confines of wildlife preserves all across the African continent [16,17,22,25]. These factors drive musth males to travel farther, faster, and with more directional purposes [11,[26][27][28][29][30]. ...
Driven by reproductive motives, male African elephants (Loxodonta africana) in musth often expand their home ranges to locate estrous females. This extended range, coupled with heightened aggression often observed in musth males, can be particularly problematic in regions where human-modified landscapes and elephant territories increasingly overlap. Several mitigation tools have been tested to resolve a wide range of human–elephant conflicts with varying degrees of success due to geographical disparities and habituation. We present findings on the potential application of estrous call playbacks in manipulating the behavior and movement of male elephants non-invasively, particularly mature musth adults and younger post-dispersal males, in Etosha National Park. Estrous vocalizations were presented across 26 experimental trials to mature musth adults (n = 5), mature non-musth adults (n = 6), and non-musth males belonging to younger, post-dispersal age classes (n = 8), with behavioral responses scored on a gradient scale from 0–1. Both mature musth adults and younger non-musth elephants were significantly more likely to respond with the highest intensity by approaching the acoustic source compared to mature non-musth adults that avoided the call. However, younger males tested in the presence of an older, higher-ranking male tended to react with a lower intensity than those tested alone. This result likely demonstrates the influence of social hierarchy and associations on male elephant behavior. We also observed a significant increase in physiological response, measured by defecation rate, across all male groups in response to the estrous call playbacks. Our findings suggest that using estrous calls as acoustic deterrents may effectively and non-invasively aid in reducing tension at the human–elephant interface, depending on the age, social context, and reproductive status of the male elephant.
... In addition to natural observations, elephants have sometimes been observed interacting with elephant bones (typically jaws or skulls) collected by humans for display at tourist or educational facilities, as has been noted elsewhere (Poole 1996). In our research camp, we collect jaws from known elephants to facilitate age estimation and for educational purposes. ...
... These behaviors are comparable to those of socially similar species like chimpanzees, in which agitated and subdued behavior has been recorded even at carcasses of unrelated conspecifics (Anderson 2018). Such behaviors have often been attributed to grief (Poole 1996;King 2013;Pierce 2013). A better understanding of elephant memory and emotionality will shed light on this phenomenon. ...
Many nonhuman animals have been documented to take an interest in their dead. A few socially complex and cognitively advanced taxa—primates, cetaceans, and proboscideans—stand out for the range and duration of behaviors that they display at conspecific carcasses. Here, we review the literature on field observations of elephants at carcasses to identify patterns in behaviors exhibited. We add to this literature by describing elephant responses to dead elephants in the Samburu National Reserve, northern Kenya. The literature review indicated that behavior of elephants at carcasses most often included approaches, touching, and investigative responses, and these occurred at varying stages of decay, from fresh carcasses to scattered and sun-bleached bones. During our own observations, we also witnessed elephants visiting and revisiting carcasses during which they engaged in extensive investigative behavior, stationary behavior, self-directed behavior, temporal gland streaming, and heightened social interactions with other elephants in the vicinity of a carcass. Elephants show broad interest in their dead regardless of the strength of former relationships with the dead individual. Such behaviors may allow them to update information regarding their social context in this highly fluid fission–fusion society. The apparent emotionality and widely reported inter-individual differences involved in elephant responses to the dead deserve further study. Our research contributes to the growing discipline of comparative thanatology to illuminate the cognition and context of nonhuman animal response to death, particularly among socially complex species.
... Asian elephants live in relatively small, dynamic family groups, and often move within dense, low-visibility forests (de Silva and Wittemyer 2012;Sukumar 2003), where vision may not be as important as olfaction and audition. African savannah elephants (Loxodonta africana), on the other hand, often move across vast, open landscapes with varying-sized family groups (Moss et al. 2011), where visual cues from conspecifics may be substantially more relevant. Thus, it is possible that these ecological differences between Asian and African elephants could explain the differences in their performance on these experiments. ...
... Given the differences in the elephants' natural environments, there is likely significant variability in the two species' foraging behaviors. Savannah elephants (Loxodonta africana) in relatively large social groups often seek out food within open savannah environments (Moss et al. 2011), where visual information about resource location may be relevant. Asian elephants (Elephas maximus), on the other hand, usually live in dense forest or jungle environments where visibility is limited (Sukumar 2003), and thus vision may not be as relevant as olfaction for locating food. ...
Asian elephants have previously demonstrated an ability to follow olfactory cues, but not human-provided social cues like pointing and gazing or orienting to find hidden food (Plotnik et al. in PLoS One 8:e61174, 2013; Anim Behav 88:91–98, 2014). In a study conducted with African elephants, however, elephants were able to follow a combination of these social cues to find food, even when the experimenter’s position was counter to the location of the food. The authors of the latter study argued that the differences in the two species’ performances might have been due to methodological differences in the study designs (Smet and Byrne in Curr Biol 23(20):2033–2037, 2013). To further investigate the reasons for these potential differences, we partially adapted Smet and Byrne (2013)’s design for a group of Asian elephants in Thailand. In a two-object-choice task in which only one of two buckets was baited with food, we found that, as a group, the elephants did not follow cues provided by an experimenter when she was positioned either equidistant between the buckets or closer to the incorrect bucket when providing the cues. The elephants did, however, follow cues when the experimenter was closer to the correct bucket. In addition, there was individual variability in the elephants’ performance within and across experimental conditions. This indicates that in general, for Asian elephants, the pointing and/or gazing cues alone may not be salient enough; local enhancement in the form of the experimenter’s position in relation to the food reward may represent a crucial, complementary cue. These results suggest that the variability within and between the species in their performance on these tasks could be due to a number of factors, including methodology, the elephants’ experiences with their handlers, ecological differences in how Asian and African elephants use non-visual sensory information to find food in the wild, or some combination of the three.
... We predict that the movement path for male and female elephants are less tortuous, have longer step lengths, longer net displacements and smaller turning angles and will show stronger directionality toward water sources in the dry season than in the wet season. Past reports indicate that elephants remember and re-visit previously visited sites (De Beer and Van Aarde, 2008;Prins and Van Langevelde, 2008;de Knegt et al., 2011;Polansky et al., 2015) and pass on the information of their historical migration routes through generations (McComb et al., 2001;Moss et al., 2011). Thus, longer step lengths and higher directionality of elephant movement paths toward water sources in the dry season is an indication that elephants use information to travel to these water sources. ...
... The difference between male and female elephants movement patterns may be also be explained by their social organization (Archie et al., 2011;Moss et al., 2011) and the difference in foraging strategy between the sexes . The foraging range of male elephants is larger than that of females as they take more risks and disperse to unfamiliar habitats to seek for food and mates Skarpe et al., 2014). ...
Water is a scarce resource in semi-arid savannas where over half of the African elephants (Loxodonta africana) populations occur and may therefore influence their movement pattern. A random search is expected for an animal with no information on the location of the target resource, else, a direction-oriented walk is expected. We hypothesized that elephants movement patterns show a stronger directional orientation toward water sources in the dry season compared to the wet season. We investigated the movement paths of four male and four female elephants with hourly GPS fixes in Tsavo National Park, Kenya in 2012–2013. Consistent with our predictions, the movement paths of elephants had longer step lengths, longer squared net displacements, and were directed toward water sources in the dry season as compared to the wet season. We argue that African elephants know the location of dispersed water resources, enabling them to survive with scarce resources in dry savannas. These results can be used in conservation and management of wildlife, through for instance, protection of preferred water sources.
... As such, human prestige is probably homologous with chimpanzee prestige, i.e., a trait derived from our common ancestor and thus more than six million years old. There is also evidence for prestige dynamics among elephants (McComb, Moss, Durant, Baker, and Sayialel, 2001;McComb, Shannon, Durant, Sayialel, Slotow, Poole, and Moss, 2011;Mutinda, Poole, and Moss, 2011;TenHouton, 2017), corvids (Fraser and Bugnyar, 2011;Kulahci, Rubenstein, Bugnyar, Hoppitt, Mikus, and Schwab, 2016) and perhaps even cetaceans (Janik, 2014;King and Janik, 2013). These species are phylogenetically distant from one another, so prestige here would probably arise from convergent (or parallel) evolution, rather than by common ancestry. ...
This essay focuses primarily on Fury (2014) and to a lesser extent on Saving Private Ryan (1998), two popular war films. I suggest cognitive mechanisms that make the actions of main characters biologically plausible and intelligible. The principal ones have to do with social status and especially prestige, which is based on certain kinds of competence, especially in heroic leaders. Prestige is understood to be co-created by leaders and followers together. Heroism is understood to be depicted in these films as effective leadership in extreme circumstances so as to solve collective action problems. Heroic qualities are signaled (honestly) by means of wounds and scars. These signals are received and understood (both in the films and in their viewers) by means of social learning and social comparison judgments that track prestige. Group cohesion is also explored, especially in Fury, in terms of shared emotions, mimicry, rituals and commitments to a common task. Hatred of morally defined out-groups is also seen at work. I conclude that these films posit warfare as one of a small number of "biologically possible arrangements" that accomplish a rare concatenation of fitness promoting goals. Some consideration is also given to what makes consilience between empirical science and cinematic imagination possible.
... Though megaherbivores may exhibit some robustness to environmental variation, we would not expect the absence of environmental stochasticity observed in the SKKR dynamics to be typical of megaherbivores, especially given the diverse habitats occupied by black rhinoceros and elephant in particular. Hrabar and du Toit (2005), Gough and Kerley (2006), Chamaillé-Jammes et al. (2008) and Lee et al. (2011) all reported influences of rainfall on the demography of megaherbivores, black rhinoceros in the first instance and African elephant in the other three. Nevertheless, Brodie et al. (2011:355) found no temporal variation in vital rates, over a 14-year period, of the black rhinoceros population they studied in the 'most extreme desert-dwelling ecotype of black rhino'. ...
Population dynamics is a central component of demography and critical for meta-population management, especially of endangered species. We employed complete individual life records to construct census data for a reintroduced black rhinoceros population over 22 years from its founding and investigated that population’s dynamics to inform black rhinoceros meta-population management practice and, more generally, megaherbivore ecology. Akaike’s information criterion applied to scalar models of population growth based on the generalized logistic unambiguously selected an exponential growth model (r = 0.102 ± 0.017), indicating a highly successful reintroduction, but yielding no evidence of density dependence. This result is consistent with, but does not confirm, the threshold model of density dependence that has influenced black rhinoceros meta-population management. Our analysis did support previous work contending that the generalized logistic is unreliable when fit to data that do not sample the entire range of possible population sizes. A stage-based matrix model of the exponential population dynamics exhibited mild transient behaviour. We found no evidence of environmental stochasticity, consistent with our previous studies of this population that found no influence of rainfall on demographic parameters. Process noise derived from demographic stochasticity, principally reflected in annual sex-specific recruitment numbers that differed from deterministic predictions of the matrix model. Demographically driven process noise should be assumed to be a component of megaherbivore population dynamics, as these populations are typically relatively small, and should be considered in managed removals and introductions. We suggest that an extended period of exponential growth is common for megaherbivore populations growing from small size and that an increase in age at first reproduction with increasing population size, manifest in the study population, may provide a warning of density feedback prior to detectable slowing of population growth rate for megaherbivores .
... African (Loxodonta africana) and Asian elephants (Elephas maximus) of both sexes engage in distinctive trunk-tip behaviours when inspecting conspecific genitalia, temporal glands, mouth, ears and feet 26 . Elephants emit chemical signals via their temporal glands, urine, faeces, breath, saliva, interdigital glands, genitalia and body surfaces, and detect both self and non-self signals via highly sophisticated olfactory and vomeronasal systems 27 . These chemical signals influence elephant behavior, social interactions and reproduction 28 . ...
Group-living animals that live in complex social systems require effective modes of communication to maintain social cohesion, and several acoustic, olfactory and visual signaling systems have been described. Individuals need to discriminate between in- and out-group odour to both avoid inbreeding and to identify recipients for reciprocal behaviour. The presence of a unique group odour, identified in several social mammals, is a proposed mechanism whereby conspecifics can distinguish group from non-group members. African elephants (Loxodonta africana) live in stable, socially complex, multi-female, fission–fusion groups, characterized by female philopatry, male dispersal and linear dominance hierarchies. Elephant social behaviour suggests that individuals use odour to monitor the sex, reproductive status, location, health, identity and social status of conspecifics. To date, it is not clear what fixed or variable information is contained in African elephant secretions, and whether odour encodes kinship or group membership information. Here we use SPME GC–MS generated semiochemical profiles for temporal, buccal and genital secretions for 113 wild African elephants and test their relationship with measures of genetic relatedness. Our results reveal the existence of individual identity odour profiles in African elephants as well as a signature for age encoded in temporal gland and buccal secretions. Olfactory signatures for genetic relatedness were found in labial secretions of adult sisters. While group odour was not correlated with group genetic relatedness, our analysis identified “group membership” as a significant factor explaining chemical differences between social groups. Saturated and short-chain fatty acids (SCFAs), derived from key volatile compounds from bacterial fermentation, were identified in temporal, buccal and genital secretions suggesting that group odour in African elephants may be the result of bacterial elements of the gut microbiome. The frequent affiliative behavior of African elephants is posited as a likely mechanism for bacterial transmission. Our findings favour flexible group-specific bacterial odours, which have already been proposed for other social mammals and present a useful form of olfactory communication that promotes bond group cohesion among non-relatives in fission–fusion mammals.
... There are, however, peaks of frequency of estrus during and shortly after the rains, and in areas of highly seasonal rainfall the great majority of breeding takes place at this time (Laws 1969;Moss 2001;. Female elephants in the wild live to over 60 years of age (Moss 2001), while reproduction generally ceases or declines markedly in their 50s (Moss and Lee 2011a). ...
How can humans and wildlife coexist? In the new book "Tarangire: Human-Wildlife Coexistence in a Fragmented Ecosystem", published @SpringerNature, we synthesize interdisciplinary research, highlight challenges & propose solutions that work for humans and wildlife.
... There are, however, peaks of frequency of estrus during and shortly after the rains, and in areas of highly seasonal rainfall the great majority of breeding takes place at this time (Laws 1969;Moss 2001;. Female elephants in the wild live to over 60 years of age (Moss 2001), while reproduction generally ceases or declines markedly in their 50s (Moss and Lee 2011a). ...
We synthesize data on the ecology of large carnivores in the Tarangire Ecosystem (TE). Despite anthropogenic pressures, all large carnivore species (lions Panthera leo, spotted hyena Crocuta crocuta, striped hyena Hyena hyena, leopard Panthera pardus, cheetah Acinonyx jubatus, and wild dog Lycaon pictus) have persisted in this fragmented ecosystem consisting of multiple protected areas among a matrix of village lands. The focal species were widely distributed across land-use gradients. While the comparatively abundant spotted hyena permanently occupied village lands, other species only sporadically used these human-dominated areas. Across species, carnivores used village lands more frequently during the rainy season, possibly following seasonal shifts in the movement of prey species. These processes can increase human-carnivore interactions, expanding the potential for conflict. In some areas, leopards, lions, and striped hyenas reached high densities, whereas cheetahs and wild dogs occurred patchily and at low densities. Our review suggests that the existence of diverse protected areas contribute to the persistence of the large carnivore community. The persistence of lions, cheetahs, and wild dogs appears dependent on human-induced mortality and prey depletion. Conserving large carnivores in TE requires the application of interventions that reduce human-induced mortality while simultaneously conserving the spatio-temporal distributions of prey species.
... There are, however, peaks of frequency of estrus during and shortly after the rains, and in areas of highly seasonal rainfall the great majority of breeding takes place at this time (Laws 1969;Moss 2001;Foley and Faust 2010). Female elephants in the wild live to over 60 years of age (Moss 2001), while reproduction generally ceases or declines markedly in their 50s (Moss and Lee 2011a). ...
The Tarangire Ecosystem is well known for its elephant population and Tarangire National Park is marketed as one of the best places in East Africa to see large herds of elephants. In the past century the elephant population in the ecosystem has undergone significant changes in response to poaching and land use changes. These have impacted elephant ranging and migration patterns and have led to dramatic alterations in the demographic structure of the population. This chapter provides a historical account of the elephant population in the Tarangire Ecosystem from the mid-1900s until the present day. Included in this chapter is how the demographic structure of the population was impacted by and has recovered from heavy elephant poaching, how the elephant range has contracted and expanded over time in response to poaching and changing land-use patterns, and how connectivity with other elephant populations has been impacted by human land use. It also describes some of the main problems that are likely to affect the elephant population in the future.
... There are, however, peaks of frequency of estrus during and shortly after the rains, and in areas of highly seasonal rainfall the great majority of breeding takes place at this time (Laws 1969;Moss 2001;. Female elephants in the wild live to over 60 years of age (Moss 2001), while reproduction generally ceases or declines markedly in their 50s (Moss and Lee 2011a). ...
Facilitating coexistence between humans and large carnivores is one of the most complex and pressing conservation issues globally. Large carnivores pose threats to human security and private property, and people may respond to those risks with retaliation which can jeopardize the persistence of carnivore populations. The nature of these interactions can be influenced by several variables including ecological, anthropogenic as well as political dimensions. The Tarangire Ecosystem (TE) of northern Tanzania is a stronghold for multiple large carnivore species. Despite multi-faceted and long-term carnivore conservation efforts being implemented in the ecosystem, the anthropogenic impacts on carnivore populations are pervasive. As only a portion of the TE is fully protected, the wide-ranging nature of carnivores brings them into close contact with people living among a matrix of village lands. Consequently, this ecosystem experiences high levels of human-carnivore conflicts. In this chapter, we synthesize the existing information to characterize the extent, impacts, and spatiotemporal patterns of human-carnivore interactions (which often result in severe conflicts, causing harm to people, livestock, and carnivores), examine the efficacy and challenges of implementing interventions designed to reduce human-carnivore conflict, and explore the socio-economic dimensions of these mitigation efforts.
... There are, however, peaks of frequency of estrus during and shortly after the rains, and in areas of highly seasonal rainfall the great majority of breeding takes place at this time (Laws 1969;Moss 2001;. Female elephants in the wild live to over 60 years of age (Moss 2001), while reproduction generally ceases or declines markedly in their 50s (Moss and Lee 2011a). ...
In the Tarangire Ecosystem, elephants frequently use pastoral areas, where they interact with people and livestock. To characterize the elephant-livestock interface in Manyara Ranch, we used a social-ecological approach to capture the herders’ and the elephants’ perspectives of these interactions. We interviewed cattle herders to assess their perceptions of elephants relative to other wildlife species (n = 117 interviews) and observed how elephants responded to sound playbacks associated with humans and cattle relative to sounds of wildlife species (n = 300 playbacks). Most herders (86%) supported elephant conservation, and reported spatial avoidance of elephants as the main strategy to avoid negative interactions. Among eleven large mammal wildlife species, herders ranked elephants as the fifth most problematic species to cattle. Elephants frequently reacted (e.g., bunching, fleeing, shaking the head and moving the trunk, or approaching) to human-related sound playbacks (79% of playbacks), and reacted less frequently when exposed to sounds of cattle (62%) or wildlife (34%). Playback experiments suggested that while elephants primarily reacted non-aggressively when faced with livestock, aggressive elephant behavior may be triggered by human behavior. Evidence from both the interview data and the behavioral experiments suggest that coexistence between elephants and pastoralists is mostly facilitated by mutual spatial avoidance.
... Developing welfare parameters for African elephants (Loxodonta africana) in fenced reserves in South Africa rubbing, or touching behaviours). Most of these have been described by other authors [37,41,65]. The term Arousal [38] is used in this study to describe any behaviour that indicates the animal is responding to an external stimulus, and may escalate from mild alertness (e.g. head Biting own trunk Trunk placed in own mouth and pulled down. ...
South Africa has many fenced reserves harbouring small to medium sized populations of African elephant (Loxodonta africana), most of which have been translocated. Elephants on fenced reserves may be exposed to various management interventions and practices (translocation, hunting, darting, high tourism impact, contraception programs, disruption due to infrastructure maintenance, etc.). These factors may impact the welfare of elephants. Poor elephant welfare may have serious consequences such as increased inter- and intra-species aggression that could result in fatalities. This is the first study to attempt to define behavioural and physiological welfare parameters for free-ranging elephants on small to medium sized reserves. The eight study sites incorporated reserves with different social structure combinations, elephant life-histories, reserve sizes, habitat, management, and tourism intensity. Data collection consisted of behavioural observations (10-minute videos) as well as faecal samples. By incorporating both behavioural and physiological (faecal glucocorticoid metabolite (fGCM) concentration) parameters, we aimed to investigate whether the two parameters showed similar trends. Five behavioural categories were identified (Arousal, Assessing, Ambivalent, Ambivalent/ Body care, and Frustrated behaviour), with various detailed behaviours demonstrated by the elephants that may indicate the influence of anthropogenic disturbance and possibly impact on animal welfare. The study showed significant differences between the selected detailed behaviours, behavioural categories and fGCM concentrations of elephants across the eight reserves. History seemed to be a decisive factor, as reserves with predominantly ex-captive elephants showed higher frequencies of certain behaviours as well as higher fGCM concentrations. Age, sex, reserve size and season were also found to contribute to our defined welfare indices and fGCM concentrations. This indicates that behavioural parameters, indicative of certain behavioural states, are valuable indicators of welfare, as supported by the physiological response of the elephants. The results also highlight the importance of taking multiple specified behaviours from a category into consideration when evaluating the welfare of elephants, to account for individual variation.
... Amboseli encompasses 390 km 2 of predominantly savanna grassland habitats that surround semi-permanent and permanent swamps, which are fed with run-off from the Kilimanjaro Mountain catchment. The Amboseli Elephant Research Project was established in 1972 and has long-term, detailed demographic records on~1500 individual elephants within the population, which make up 58 distinct family groups [40]. Individuals born after 1972 have been accurately aged, while the ages of the older elephants were estimated using criteria that are accepted as a standard in studies of African elephants, including the length of the hind footprint, dentition, shoulder height and back length [41]. ...
The transmission of reliable information between individuals is crucial for group-living animals. This is particularly the case for cognitively advanced mammals with overlapping generations that acquire detailed social and ecological knowledge over long lifetimes. Here, we directly compare the ecological knowledge of elephants from two populations, with radically different developmental histories, to test whether profound social disruption affects their ability to assess predatory threat. Matriarchs (≤50 years of age) and their family groups received playbacks of three lions versus a single lion roaring. The family groups in the natural Amboseli population (Kenya) reliably assessed the greater predatory threat presented by three lions roaring versus one. However, in the socially disrupted Pilanesberg population (South Africa), no fine-scale distinctions were made between the numbers of roaring lions. Our results suggest that the removal of older and more experienced individuals in highly social species, such as elephants, is likely to impact the acquisition of ecological knowledge by younger group members, particularly through the lack of opportunity for social learning and cultural transmission of knowledge. This is likely to be exacerbated by the trauma experienced by juvenile elephants that witnessed the culling of family members and were translocated to new reserves. With increasing levels of anthropogenic disturbance, it is important that conservation practitioners consider the crucial role that population structure and knowledge transfer plays in the functioning and resilience of highly social and long-lived species.
... and L. africana83,85 . We added a few taxa not previously included by the original authors, using individual body masses from Oboussier's database (Unpublished data field book H. Oboussier, collections of the Zoological Institute and Museum, University Hamburg, Germany). ...
The 1-m-tall dwarf elephant Palaeoloxodon falconeri from the Pleistocene of Sicily (Italy) is an extreme example of insular dwarfism and epitomizes the Island Rule. Based on scaling of life-history (LH) traits with body mass, P. falconeri is widely considered to be ‘r-selected’ by truncation of the growth period, associated with an early onset of reproduction and an abbreviated lifespan. These conjectures are, however, at odds with predictions from LH models for adaptive shifts in body size on islands. To settle the LH strategy of P. falconeri, we used bone, molar, and tusk histology to infer growth rates, age at first reproduction, and longevity. Our results from all approaches are congruent and provide evidence that the insular dwarf elephant grew at very slow rates over an extended period; attained maturity at the age of 15 years; and had a minimum lifespan of 68 years. This surpasses not only the values predicted from body mass but even those of both its giant sister taxon (P. antiquus) and its large mainland cousin (L. africana). The suite of LH traits of P. falconeri is consistent with the LH data hitherto inferred for other dwarfed insular mammals. P. falconeri, thus, not only epitomizes the Island Rule but it can also be viewed as a paradigm of evolutionary change towards a slow LH that accompanies the process of dwarfing in insular mammals.
... More time was lost by children and adults in AE due to the location of schools within wildlife dispersal and migratory routes compared to MKE. According to Croze and Moss (2011) wildlife species such as elephants, zebra and buffaloes spent about 80% of their time outside the Amboseli National Park. The Park is not fenced and there is free movement of wildlife compared to MKE, where wildlife movement is restricted by the wide spread electric fences around conservation areas. ...
Traditionally, the cost of Human-wildlife conflict (HWC) has largely focused on visible costs, ignoring the hidden costs (HC). The HC of HWC are losses that are uncompensated, temporarily delayed, or psychosocial in nature. HC, such as opportunity costs (OC) are scantly documented to inform policy changes for addressing HWC. This study demonstrates the importance of considering HC using Amboseli Ecosystem (AE) and Mt. Kenya Ecosystem (MKE) in Kenya. The objectives of this study were to: a). quantify the economic magnitude of the OC of HWC and its impacts on human wellbeing; b) compare the time and monetary OC; c) make recommendations for HWC related policy reform. Data was collected from 408 households using a multi-stage sampling technique. Opportunity costs were conceptualised as the mean time and money lost due to wildlife presence and attacks. Analysis indicates that the hours spent guarding livestock (t = 3.820, d.f = 110, p = 0.000) and crops (t = 3.571, d.f = 130, p = 0.00) in AE and MKE at night were significantly different. Conversely, daytime hours spent guarding livestock and crops in AE and MKE were similar (P > 0.05). On average, AE households spent KES 208, 540 (US1205) guarding livestock and crops. School children in AE lost more time in the morning (1.28 ± 0.053 h; n = 98) and in the evening (1.22 ± 0.044 h; n = 93) than in MKE. Overall, OC were more in AE than MKE, suggesting that HC varies with ecosystems. A review of the wildlife compensation policy and law to include HC can help deter resentments resulting from uncompensated HWC costs.
... Kin recognition and recognition of other elephants they have crossed paths with possibly decades earlier, grieving behaviours, and complex play and social learning behaviours have all been well described [5,6]. Long-term (lifelong, following several generations) studies such as those conducted in Amboseli National Park [7] have provided huge insight into the behavioural repertoire of elephants, their communication, and how these behaviours and resulting highly related herds could be affected by anthropogenic change. Ex situ, modern captive settings strive to provide an environment which can not only provide the species' basic ecological needs, but also takes individual needs and preferences into account, being enriching and dynamic enough to work towards the highest possible welfare through opportunities for natural behavioural expression [8]. ...
Elephants are highly intelligent animals with a huge capacity for social cognition, living in large, long-lived, related herds. In captivity, it is extremely difficult to meet all of the species’ ecological needs, as well as those required individual by individual, but improvements are continually being made. After identifying impaired welfare, one collection made the decision to relocate four female African Elephants (Loxodonta africana) to a different facility. As the worlds’ largest land mammal, many safety, welfare, and logistical considerations were undertaken. The elephants travelled in two pairs, a mother–daughter pair and an older unrelated female and a younger unrelated female with a strong social bond. As a result, there was a short gap in between transports, allowing for further habituation to transport crates and the heat of summer. The changes in both social and individual behaviours of the two females remaining when their group was temporarily reduced from four to two were investigated using one-zero sampling. The study determined the daily activities of the elephants comparing ‘before transport’ to ‘after transport’ for the two remaining elephants to establish any changes in their behaviours as a result of this disturbance. Post transport, there was an increase in both human-audible vocalisations and temporal gland secretions, and hugely decreased play behaviour was observed. The dynamic between the remaining pair was also altered with more tactile behaviours from mother to daughter seen but more submission from daughter to mother. This led to the conclusion that the elephants, although mostly unrelated and living in an ‘unnatural’ captive setting, had the same signs of stress and behavioural change as would a highly related group if separated.
... Although males reach sexual maturity around 10-12 years of age, they do not generally reach their sexual peak until their thirties (Laws, 1969;Poole, 1987;Sukumar, 1989;Poole, 1994;Turkalo et al., 2017). Females become sexually mature between 8 and 12 years, and are in oestrus for only four to six days every four to five years -assuming they conceive each time they are sexually receptive and ovulate (Sukumar, 1989(Sukumar, , 2003Freeman et al., 2009;Moss et al., 2011;Brown, 2014). As such, males often engage in contest competition for access to receptive females, potentially year-round depending on female receptivity (Poole, 1989a;Sukumar, 1989;Vidya & Sukumar, 2005;Keerthipriya et al., 2020). ...
Sexual selection mediated by multimodal signals is common among polygynous species, including seasonally breeding mammals. Indirect benefit models provide plausible explanations for how and why mate selection can occur in the absence of direct benefits. Musth-an asynchronous reproductive state in male elephants-facilitates both inter-and intrasexual selection via indirect benefits, and it is further communicated through a multimodal signal. In this review, we synthesise existing evidence that supports the hypothesis that musth is a multimodal signal subject to sexual selection and that male elephants increase their direct fitness by propagating this signal while females accrue indirect benefits. Musth is characterised by a suite of physiological and behavioural changes, serving to facilitate copulation between the sexes, and via multisensory modalities musth conveys honest information about the condition of a male. Female elephants mate preferentially with musth males, increasing their own fitness in the absence of direct benefits. In addition, musth resolves dynamic dominance hierarchies among male elephants and often eliminates the need for costly physical combat. Future work in this field should investigate potential postcopulatory selection mechanisms in elephants, including sperm competition and cryptic female choice. These topics join other fundamental questions related to sexual selection, signalling, and indirect benefits that are still unanswered in elephants.
... Furthermore, all species that exhibit persistent relationships across developmental stages (including with maternal kin) appear to share one thing in common, which is that individuals exhibit persistent relationships with partners that represent the greatest value. These valuable partners are maternal kin in baboons and elephants (Moss et al. 2011;Silk et al. 2010b;Silk et al. 2006b), ecologically-knowledgeable mothers in orcas (Brent et al. 2015;Foster et al. 2012), mothers in codominant bonobos (Surbeck et al. 2011(Surbeck et al. , 2019, and adult males in the male-dominated societies of chimpanzees, bottlenose dolphins, and mountain gorillas (Goodall 1986;Mitani 2009b;Robbins et al. 2001;Samuels and Gifford 1997). ...
Highly differentiated and affiliative social relationships are observed in a variety of mammals, including primates, cetaceans, and social carnivores. Although there has been a transformation in our understanding of the form and function of social bonds in the past two decades, the role of early life social experiences in the development of bonds remains less clear. Few studies have examined whether social relationships during infancy and juvenility (aside from those between mothers and offspring) persist into adulthood. In this study, we used longitudinal data on wild chimpanzees (Pan troglodytes schweinfurthii) at Gombe National Park, Tanzania, to investigate the effects of party-level association during infancy and juvenility (hereafter immaturity) on affiliative relationships among adult males (the philopatric sex). In total, we examined behavioral data from focal follows between 1970 and 2015 (N = 23 adult males). We used maternal associations as proxies for the associations of immature males, and we measured adult male social relationships using party-level associations and grooming activity. We found that immature males that associated with individual adult males at higher rates had stronger relationships with those same adult males later in life. By contrast, rates of association between pairs of immature males did not predict the strength of their dyadic relationships as adults. Overall, these findings emphasize the importance of early socialization in male chimpanzee social development. These results also reinforce studies in mountain gorillas (Gorilla beringei) and bottlenose dolphins (Tursiops sp.), suggesting that the persistence of social relationships that do not involve the mother may be more likely to evolve in long-lived species where young adult males face challenges entering an adult hierarchy composed of stronger and/or more socially experienced competitors.
... Our study allowed for testing wild animals over a long time period (mean of 402.8 days between the first and last recording of the same individual) to confirm the presence of individually distinct vocalizations while concurrently indicating the robustness of male vocalizations over time. Rumbles are used by African elephants in many different contexts (Moss, Croze & Lee, 2011) and the vocalizations used in our analysis were recorded while elephants displayed various behaviors. Despite this, the individual differences were pronounced, suggesting that rumbles can provide reliable information about identity across a variety of behavioral contexts. ...
The ability to recognize conspecifics plays a pivotal role in animal communication systems. It is especially important for establishing and maintaining associations among individuals of social, long-lived species, such as elephants. While research on female elephant sociality and communication is prevalent, until recently male elephants have been considered far less social than females. This resulted in a dearth of information about their communication and recognition abilities. With new knowledge about the intricacies of the male elephant social structure come questions regarding the communication basis that allows for social bonds to be established and maintained. By analyzing the acoustic parameters of social rumbles recorded over 1.5 years from wild, mature, male African savanna elephants ( Loxodonta africana ) we expand current knowledge about the information encoded within these vocalizations and their potential to facilitate individual recognition. We showed that social rumbles are individually distinct and stable over time and therefore provide an acoustic basis for individual recognition. Furthermore, our results revealed that different frequency parameters contribute to individual differences of these vocalizations.
... A species' ability to cope with the changing selective forces resulting from anthropogenic disturbance may be partially determined by the amount of genetic variability in populations as well as the way that variation is structured within and between populations (Archie et al., 2011;Ishida et al., 2016). Evidence for recent emergence of genetic structure within the three studied elephant populations suggests that habitat loss and fragmentation in the areas between Ruaha and Katavi are starting to alter population connectivity. ...
Habitat fragmentation plays a major role in the reduction of genetic diversity among wildlife populations. The African savannah elephant population of the Ruaha-Rungwa and Katavi-Rukwa ecosystems in south-western Tanzania, comprises one of the world’s largest remaining elephant populations, but is increasingly threatened by loss of connectivity and poaching for ivory. We investigate whether there are incipient signs of genetic isolation (loss of heterozygosity) within the younger cohort as a result of habitat loss between the two ecosystems. To investigate the genetic structure of populations, we compared the genotypes for 11 microsatellite loci in the western (n = 81 individuals from Katavi-Rukwa), central (n = 36 individuals from Lukwati and Piti), and eastern populations (n = 193, individuals from Ruaha-Rungwa). We found evidence of significant genetic differentiation among the three populations, but the levels were low, suggesting recent divergence. Furthermore, we identified weak isolation by distance, suggesting higher gene flow among nearer individuals with samples within 50km of each other being more genetically similar to one another than beyond. Although sample sizes were small, a further analysis of genetic differences across populations and in separate age classes revealed evidence of increasing genetic structure among younger age classes across the landscape. In a long-lived species with overlapping generations, it takes a long time to develop genetic substructure even when there are substantial obstacles to migration. Thus, in these recently fragmented populations, inbreeding (and the loss of heterozygosity) may be less of an immediate concern than demography (the loss of adults due to illegal hunting).
... In another study of Asian elephant cognition, the elephants used an experimenter's position, not visual pointing and gaze cues, in relation to food to locate the food (via local enhancement, Ketchaisri et al., 2019). Juvenile elephants learn to use their trunk and forage by interacting with related conspecifics (Lee & Moss, 2011), yet Achara, the youngest subject, did not copy demonstrator Chandra (Achara's aunt) at OKC. Kandula exhibited insightful problem solving on another task (Foerder et al., 2011) but not in the present study, though his mother, Shanthi, did solve the present task. Unfortunately, we could not have Shanthi (NZP) demonstrate for her son, Kandula (OKC), because of their separate housing, but it would be informative to test closely related demonstrator-observer pairs (copy kin strategy: Laland, 2004). ...
One of the greatest challenges in comparative cognition is to design tasks that accurately assess cognitive abilities across a diverse set of taxa with differing morphologies and behaviors. The floating object task was designed to test insightful problem solving via water tool use in animals but so far has been tested only in primates. In the floating object task, animals add water to a tube in order to reach a floating food reward. A similar task, the Aesop's fable task, which is solved by adding stones to the tube, has been used with corvids and raccoons in addition to human children. Elephants are considered to exhibit complex cognitive abilities on par with primates, and they possess a prehensile trunk appendage well-suited for tests of water tool use. Here, we presented the floating object task to 12 zoo-housed Asian elephants (Elephas maximus) to determine if they demonstrate innovative problem solving or social learning. One elephant solved the task on her own. Additionally, elephants at one zoo that observed a conspecific solve the task exhibited increased interest in the task compared to baseline elephants, demonstrating social learning via stimulus enhancement. Asian elephants are capable of learning to use water as a tool, but the cognitive abilities underpinning their ability to solve the floating object task remain unclear. Our findings may bolster support for the convergent cognitive evolution of problem solving in elephants and apes, but further research using additional paradigms is needed.
... The SGR project's impact on the lifestyle of (Jachowski, 2012).This piece of work is described within the scientific community as a compendium of biological, ecological, and natural history knowledge on elephants. ...
Every wildlife species has a language or 'signal' for communication both within and without. In addition, the interaction between wildlife species and their natural habitat is usually a balanced system. But it is always the entry of man and his insatiable exploitative appetite into this union that is the cause of problems in this natural ecosystem. The case of land use and land use change comes into focus particularly the ones that lead to wildlife habitat fragmentation. A lot of pioneer ecological studies have looked at the effect of landscape modification on the life of wildlife. Very few, if any, have attempted to assess the inaudible voices from the wildlife habitat as a response to the said modifications. This paper used Narration Review (NR) method to analyze previous elephants' behavior observation study projects in Tsavo and Amboseli ecosystems in Kenya. A total of five papers were identified for sysnthesis.All the five papers discussed the response of elephants in terms of usage of wildlife crossing structures (CS) that were installed during the construction of Mombasa-Nairobi leg of Standard Gauge Railway (SGR) project that was commissioned in 2017. It was established that understanding the behavior of elephants in their local rangeland can help position crossings for landscape connectivity. Secondly, the SGR project's operation has come with an increasing trend of elephants' mortality in some of its corridor locations. Interestingly however, it was reported that elephant's high cognitive intelligence facilitates their faster learning of use of crossing underpasses compared to the rate of response by other wildlife species. The paper recommends for the initiation of more animals' behavior observation projects to help in development planning decision on their ethical treatments. This study contributes to the entrenchment of sustainability thinking in wildlife conservation efforts in the face of piquing demand for infrastructure development, especially in the sub Saharan Africa region which still has a huge gap.
... From the few studies that have been able to access longitudinal records of wild or free-ranging long-lived mammals, powerful empirical evidence highlights the need to further explore the evolutionary significance of maternal relatives, particularly that associating with maternal relatives increases care for dependent young [14,15] while also decreasing infant mortality [16,17]. More generally, the presence of close female maternal kin (mothers and sisters) has been found to significantly improve female reproductive success (non-human primates [18][19][20], cetaceans [21,22] and elephants [12,23]). These results parallel those from human studies, which show that female reproductive success improves with help from mothers and pre-reproductive daughters [24][25][26]. ...
Preferential treatment of kin is widespread across social species and is considered a central prerequisite to the evolution of cooperation through kin selection. Though it is well known that, among most social mammals, females will remain within their natal group and often bias social behaviour towards female maternal kin, less is known about the fitness consequences of these relationships. We test the fitness benefits of living with maternal sisters, measured by age-specific female reproduction, using an unusually large database of a semi-captive Asian elephant ( Elephas maximus ) population. This study system is particularly valuable to an exploration of reproductive trends in a long-lived mammal, because it includes life-history data that span multiple generations, enabling a study of the effects of kinship across a female's lifespan. We find that living near a sister significantly increased the likelihood of annual reproduction among young female elephants, and this effect was strongest when living near a sister 0–5 years younger. Our results show that fitness benefits gained from relationships with kin are age-specific, establish the basis necessary for the formation and maintenance of close social relationships with female kin, and highlight the adaptive importance of matriliny in a long-lived mammal.
This article is part of the theme issue ‘The evolution of female-biased kinship in humans and other mammals'.
... The dashed line shows elephant population size in 2017 (n = 1,247). Maps: Black polygons = remaining elephant habitats; grey polygons = lost habitats of many unplanned developments (Croze, Moss, & Lindsay, 2011;Schüßler, Lee, & Stadtmann, 2018). Community choices and human tolerance will shape Amboseli's conservation success, and our model has begun to identify how these choices would impact elephants. ...
Global ecosystem change presents a major challenge to biodiversity conservation, which must identify and prioritize the most critical threats to species persistence given limited available funding. Mechanistic models enable robust predictions under future conditions and can consider multiple stressors in combination. Here we use an individual‐based model (IBM) to predict elephant population size in Amboseli, southern Kenya, under environmental scenarios incorporating climate change and anthropogenic habitat loss. The IBM uses projected food availability as a key driver of elephant population dynamics and relates variation in food availability to changes in vital demographic rates through an energy budget. Habitat loss, rather than climate change, represents the most significant threat to the persistence of the Amboseli elephant population in the 21st century and highlights the importance of collaborations and agreements that preserve space for Amboseli elephants to ensure the population remains resilient to environmental stochasticity.
... Conspicuous vocal signals may also accompany copulation events in some species. In African elephants, Loxodonta africana, copulation is signaled by way of the loud and overlapping calls made by many members of the female's family, for which scientists have termed it "the mating pandemonium" (Payne, 2003;Poole, 2011). Within a given area, these loud vocalizations could presumably serve to measure copulation events directly. ...
The popularity of bioacoustics for threatened species monitoring has surged. Large volumes of acoustic data can be collected autonomously and remotely with minimal human effort. The approach is commonly used to detect cryptic species and, more recently, to estimate abundance or density. However, the potential for conservation‐relevant information to be derived from acoustic signatures associated with particular behavior is less well‐exploited. Animal vocal behavior can reveal important information about critical life history events. In this study, we argue that the overlap of the disciplines of bioacoustics, vocal communication, and conservation behavior—thus, “acoustic conservation behavior”—has much to offer threatened species monitoring. In particular, vocalizations can serve as indicators of behavioral states and contexts that provide insight into populations as it relates to their conservation. We explore the information available from monitoring species' vocalizations that relate to reproduction and recruitment, alarm and defense, and social behavior, and how this information could translate into potential conservation benefits. While there are still challenges to processing acoustic data, we conclude that acoustic conservation behavior may improve threatened species monitoring where vocalizations reveal behaviors that are informative for management and decision‐making.
... Members of a family unit exhibit a linear age-structured dominance hierarchy and the social rank is an important mediator in avoiding within-group conflict over resources (e.g. Moss et al. 25 ). Exhibiting consistent and predictable behavioural types or personalities could further improve the resolution of within-group conflict, with different personalities adopting different social roles when confronted with social challenges 26 . ...
Personality, i.e. consistent between-individual differences in behaviour, has been documented in many species. Yet little is known about how males and females of long-lived, highly social species differ in their measures of personality structure. We investigated sex differences in the mean, variance, and covariance of three previously reported personality traits (Attentiveness, Sociability, Aggressiveness) in 150 female and 107 male Asian elephants (Elephas maximus) from a semi-captive population in Myanmar. These three personality traits were obtained by performing exploratory factor analysis on 28 behavioural items that had been rated by experienced elephant handlers. We found that males scored significantly higher on Aggressiveness and tended to score lower on Sociability than females. However, no sex difference was found in the mean scores of Attentiveness. Variances for the three personality traits did not differ between the sexes, suggesting that male and female elephants share the same range of personality variation. Likewise, trait covariances were similar between the sexes. While both sexes show complex sociality in the wild, female Asian elephants typically live in highly social family units, whereas male elephants’ social bonds are weaker. Males usually form dominance ranks by aggressive interactions, especially during musth. Our results on a large sample of individuals living in their natural environment are thus in agreement with elephant life-histories and parallel the findings of sex differences in other long-lived highly social species with similar life-histories.
... year in Amboseli ecosystem begins in October and ends the following September and is linked closely to the annual cycle of growth of vegetation in the study site [46]. It is also evident in Amboseli ecosystem that the shorter rainfall season of October-November-December (OND) receives more rainfall compared to the long-rains of March-May season (MAM). ...
Within savanna environments, movements of elephant are influenced by changes in climate especially seasonal rainfall. In this study, we investigated the possible changes in elephant population based on projected rainfall changes using regional climate models (RCM) and Representative Concentration Pathways (RCPs). The relationship between elephant and rainfall was modelled against annual, wet season, dry season rainfall based on various time lags. Future relation between elephant and rainfall was projected based on three RCPs; 2.6, 4.5 and 8.5. There was a strong linear relationship between elephant and October-November-December (OND) rains with time lag of 13 years (Y = −4016.43 + 19.11x, r2 = 0.459, P = 0.006). The rainfall trends for RCP 2.6 and 4.5 showed a slight increase in annual rainfall for the period 2006-2100 but driven by OND increases. Rainfall increase for RCP 8.5 was significant and was driven by increase in both March-April-May (MAM) and OND. These rainfall dynamics had influence on the projected elephant population in the Amboseli ecosystem. For RCP 2.6 and 4.5 the elephant population increase was 2455 and 2814 respectively. RCP 8.5 elephant population doubled to an average of 3348 elephants. In all the RCPs there are seasonal and yearly variations and absolute number varies from the average. The range of variation is small in RCPs 2.6 and 4.5 compared to RCP 8.5. Evidently, elephant population will increase based on projected rainfall projections surpassing park capacity. It therefore, requires that the Park authority put in place measures that could contain these numbers including opening of blocked wildlife corridors, maintain the cross border movement of Amboseli elephant with Tanzania in that case ensure there is no poaching. Lastly, work with local communities so that they can benefit from tourism through setting up conservancies through which they could minimize the human elephant conflicts based on the projected elephant population.
Keywords
Representative Concentration Pathways 2.6, 4.5 and 8.5, Rainfall Variability, Population Dynamics
... Elephant populations still occur in the same areas; although migrations of the Amboseli elephants ceased between 1977 and 1991 due to insecurities, former ranging patterns were resumed afterwards (Koch et al. 1995). Genetic studies on mitochondrial DNA sequences of Kenyan elephants highlight the connectivity of populations across the international border Archie et al. 2011). In the eastern extent, elephants from Tsavo West can disperse towards Tsavo East NP and the Tanzanian Mkomazi NP (Ngene et al. 2017a). ...
Context
East African ecosystems are characterized by the migrations of large herbivores that are highly vulnerable to the recent development of anthropogenic land use change.
Objectives
We analyzed land cover changes in the Kenyan-Tanzanian borderlands of the greater Amboseli ecosystem to evaluate landscape connectivity using African elephants as an indicator species.
Methods
We used multi-temporal Landsat imagery and a post classification approach to monitor land cover changes over a 43-year period. GIS based methods were accompanied by a literature review for spatial data on land cover changes and elephant migrations.
Results
Land cover changed considerably between 1975 and 2017. Wood- and bushlands declined by 16.3% while open grasslands increased throughout the study region (+ 10.3%). Agricultural expansion was observed (+ 12.2%) occupying important wildlife habitats and narrowing migration corridors. This development has led to the isolation of Nairobi National Park which was previously part of a large contiguous ecosystem. Eight migration corridors were identified of which only one is formally protected. Two others are almost completely blocked by agriculture and three are expected to become endangered under continuing land use changes.
Conclusions
Landscape connectivity is still viable for this ecosystem (except for Nairobi National Park). However, the current situation is very fragile as anthropogenic land use changes are threatening most of the identified large mammal migration corridors. Sustainable land use planning with regard to important wildlife habitats and connecting corridors is a crucial task for further conservation work to safeguard a viable future for wildlife populations in the Kenyan-Tanzanian borderlands.
... The study was carried out in the Amboseli basin (bounding coordi- Amboseli elephants. Target females were selected based on more than 40 years of observations to represent the known diversity in dispersal areas and foraging opportunities in Amboseli (which are lar- gely inherited through generations unless disrupted by human distur- bance; Croze & Moss, 2011;Moss, 1988) and to minimize risks to target elephants, family members and staff. Individual females were selected according to ethical and safety criteria, minimizing the dis- turbance of each intervention. ...
The ability of animals to adapt to their changing environment will depend in part on shifts in their ranging patterns, but when and why individuals choose to move requires detailed understanding of their decision-making processes. We develop a simple decision-making model accounting for resource availability in habitually used ranges. We suggest that disparities between model predictions and animal tracking data indicate additional factors influencing movement decisions, which may be identified given detailed system-specific knowledge. The model was evaluated using movement data from satellite-tracked elephants (Loxodonta africana) inhabiting the Amboseli basin in Kenya, moving from savannah areas with low quality but constant resource availability, to areas with temporally constrained higher nutrient availability. Overall, the model fits the data well: There was a good correlation between predicted and observed locations for the combined data from all elephants, but variation between individuals in how well the model fits. For those elephants where model predictions were less successful, additional factors likely to affect movement decisions, including reproduction, anthropogenic threats, memory and perception are suggested. This protocol for building and testing decision-making models should contribute to success in attempts to preserve sufficient space for large herbivores in their increasingly human-dominated ecosystems.
... For example, vampire bats, Desmodus rotundus, regurgitate for unrelated roostmates, which is thought to expand their future meal donor networks (Carter & Wilkinson, 2015), and spotted hyaenas, Crocuta crocuta, choose social partners based on dominance rank to maximize feeding opportunities (Smith, Memenis, & Holekamp, 2007). While some work has demonstrated that individuals strengthen bonds with other relatives in response to familial loss (Silk, Altmann, & Alberts, 2006), social expansion beyond kin following bond loss has also been found: army ants (Dorylus molestus) with a dead queen fuse with neighbouring colonies despite low relatedness (Kronauer, Sch€ oning, D'Ettorre, & Boomsma, 2010), and elephants (Charif et al., 2005;Moss & Lee, 2011;Vidya, Varma, Dang, Van Thanh, & Sukumar, 2007;Wittemyer et al., 2009) and humans (Goldenberg, 2009) strengthen bonds with nonkin in response to severe societal disruption. Quantifying social interaction differences across individuals with different histories can elucidate relative costs and benefits of social expansion following disruption, offering insight regarding the degree to which such behaviour is compensatory and the nature of associated costs. ...
Social environments are fundamental to fitness in many species. In disrupted societies, the loss of important partners may alter social environments for surviving individuals. African elephants, Loxodonta africana, have experienced age-selective mortality linked to the ivory trade, and the resulting social costs for surviving young elephants are unknown. In this study, we followed orphaned female elephants and nonorphaned counterparts in Kenya's Samburu and Buffalo Springs National Reserves to elucidate whether orphaning and related dispersal behaviour incur social costs. There were clear social differences between orphans and nonorphans, most notably in that orphans tended to receive more aggression than nonorphans. Dispersal from natal groups was a behaviour found exclusively among orphans. Differences in social environments of orphans that remained in their natal groups and those that dispersed were also found in the form of dispersed orphans receiving more aggression while feeding than those that remained in their natal group. Our results suggest that orphaning in elephants is associated with social costs, and that these costs are amplified for orphans that disperse from their natal groups. Future research should identify the relationship between the social costs of being an orphan and fitness, which may be important to the recovery of populations affected by the ivory trade and other forms of disruption.
... Ils vivent alors seuls ou en compagnie d'autres mâles. Cependant, les relations au sein d'un tel groupe ne sont pas aussi fortes qu'au sein du troupeau et seuls les mâles dominants peuvent se reproduire (Olivier 1982 ;McCombe et al. 2011 ;Moss et al. 2011). ...
How does an elephant population recover after being pushed to the brink of extinction? In this and a separate paper on behaviour we present an account of war-induced collapse and post-war recovery of an elephant population. Mozambique’s 15-year civil war from 1977–1992 had a profound impact on the elephants of Gorongosa National Park. Elephant numbers plummeted from ~2,200 pre-war to <200 post-war impacting the structure of the population and its families, the physical appearance of the elephants, their genetic make-up and behaviour (companion study). Using individual registration, this study aimed to collect baseline data to estimate the population size, reproductive parameters and growth and to document its composition, including age and sex structure, tusk configuration, family and clan membership. A quarter of a century after the war, rapid reproductive rate and growth in numbers are indications of recovery, but the skewed sex ratio among older age classes and the prevalence of tusklessness in post-war generations are evidence of long-lasting scars. Additional Keywords: Age at first birth, inter-calf interval, growth rate Comment les populations d’éléphants parviennent-elles à se rétablir après avoir été poussées à la limite de l’extinction? Dans ce document — et dans une seconde publication traitant du comportement — nous présentons un compte-rendu de la chute du nombre d’individus provoquée par le conflit au Mozambique, puis de son rétablissement au lendemain de la guerre. Les quinze ans de guerre civile de 1977 à 1992 ont eu de profondes répercussions sur les éléphants du parc national de Gorongosa. Près de 2200 avant la guerre, leur nombre a chuté en deçà de 200, affectant la structure de la population et les familles qui la composent, l’apparence physique des éléphants, leur constitution génétique et leur comportement (étude parallèle). À l’aide de la reconnaissance individuelle, la présente étude a pour objectif de collecter des données de référence afin d’estimer la densité de cette population, ses paramètres de reproduction et sa croissance. Il s’agit également d’en documenter la composition, notamment la répartition des âges et des sexes, la configuration des défenses, la famille et l’appartenance au clan. Un quart de siècle après la guerre, le taux de reproduction rapide et le nombre croissant d’individus sont des indicateurs de rétablissement, mais un rapport des sexes déséquilibré parmi les classes d’âges les plus avancées et l’absence de défenses dans les générations nées après la guerre sont les preuves de séquelles durables. Mot-clés supplémentaires: âge de la première naissance, intervalle entre les naissances, taux de croissance
Simple Summary
African elephants are known for their long memory; this is also valid for their olfactory sense and their ability to discriminate scents. This feature is highly important for these mammals to maintain their family bonds and to differentiate between familiar and unfamiliar individuals. Thus far, scientific data only testify to an olfactory memory of up to one year for African elephants. This study investigated the long-term olfactory memory of two mother-daughter pairs that were separated for 2 and 12 years, respectively. Results showed that all four elephants were able to recognize their separated relatives just by the scent of feces, thereby giving the empirical implication of olfactory memory in African elephants of up to 12 years.
Abstract
African elephants are capable of discriminating scents up to a single changed molecule and show the largest reported repertoire of olfactory receptor genes. Olfaction plays an important role in family bonding. However, to the best of our knowledge, no empirical data exist on their ability to remember familiar scents long-term. In an ethological experiment, two mother-daughter pairs were presented with feces of absent kin, absent non-kin, and present non-kin. Video recordings showed reactions of elephants recognizing kin after long-term separation but only minor reactions to non-kin. Results give the empirical implication that elephants have an olfactory memory longer than 1 year and up to 12 years and can distinguish between kin and non-kin just by scent. These findings confirm the significance of scent for family bonds in African elephants.
Although social behaviour is common in group-living mammals, our understanding of its mechanisms in long-lived animals is largely based on studies in human and non-human primates. There are health and fitness benefits associated with strong social ties, including increased life span, reproductive success, and lower disease risk, which are attributed to the proximate effects of lowered circulating glucocorticoid hormones. However, to deepen our understanding of health-social dynamics, we must explore species beyond the primate order. Here, using Asian elephants as a model species, we combine social data generated from semi-captive timber elephants in Myanmar with measurements of faecal glucocorticoid metabolite (FGM) concentrations. These data enable a “natural experiment” because individuals live in work groups with different demographic compositions. We examine sex-specific FGM concentrations for four different aspects of an individuals’ social world: general sociality, work group size, sex ratio and the presence of immatures (< 5 years) within the work group. Males experienced lower FGM concentrations when engaged in more social behaviours and residing in female-biased work groups. Surprisingly, females only exhibited lower FGM concentrations when residing with calves. Together, our findings highlight the importance of sociality on individual physiological function among elephants, which may have broad implications for the benefits of social interactions among mammals.
There has been extensive research on the ecology and evolution of social life in animals that live in groups. Less attention, however, has been devoted to apparently solitary species even though recent research indicates that they also possess complex social behaviors. To address this knowledge gap, we artificially selected on sociability, defined as the tendency to engage in non-aggressive activities with others, in fruit flies. Our goal was to quantify the factors that determine the level of sociability and the traits correlated with this feature. After 25 generations of selection, the high sociability lineages showed sociability scores about 50% higher than did the low sociability lineages. Experiments using the evolved lineages indicated that there were no differences in mating success between flies from the low and high lineages. Both males and females from the low lineages, however, were more aggressive than males and females from the high lineages. Finally, the evolved lineages maintained their sociability scores after ten generations of relaxed selection, suggesting no costs to maintaining low and high sociability, at least under our settings. Sociability is a complex trait, which we currently assess through genomic work on the evolved lineages.
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We review studies of the social systems of the living elephants—the Asian elephant (Elephas maximus), African savannah elephant (Loxodonta africana), and African forest elephant (Loxodonta cyclotis). Social systems include social organisation, the way relationships are structured, and the mating system; we describe each of these in turn, drawing from long-term observational studies and studies based on indirect methods in more inaccessible populations. Male and female elephants exhibit different adult lifestyles: females live in fission–fusion societies, whereas males disperse from their natal groups and subsequently associate with other males and females only temporarily. Associations and dominance relationships among females and among males may be complex and structured by factors such as genetic relatedness and relative ages. Elephants are polygynous and males compete amongst themselves for access to females. The outcome of such competition may be shaped by musth (a rut-like phenomenon) and age. Molecular markers have been used to understand aspects of social structure and mating system in some populations; we point to these studies and discuss further avenues of research. We also comment on how anthropogenic activities affect social systems, and the relevance of studying social systems in the context of conservation.
African elephant calves are highly social and their behavioral development depends heavily on interactions with other elephants. Evaluating early social behaviors offers important information that can inform management decisions and maximize individual- and population-level welfare. We use data collected from the population of elephants at the San Diego Zoo Safari Park in Escondido, CA to evaluate developmental trajectories of spatial independence and social behavior in nine elephant calves across a range of ages. As calves aged, the probability of being further from mothers also increased. Tactile interactions were common among calves, with all individuals either initiating or receiving physical touches from other elephants in a large proportion of focal scans. While the probability of initiating tactile interactions tended to decline with increases in calf age, the probability of receiving tactile interactions from other elephants remained invariant with regard to this variable. The social play was also common, occurring in a fifth of all focal scans. While there was evidence that social play tended to decline with increases in calf age, results suggest additional factors may be useful in characterizing patterns in play behavior at the individual level. Calves most frequently engaged in play with individuals of similar age but showed substantial variation in play partner choice. Results of this study suggest that maintaining groups of elephants in captivity with diverse age structure positively contribute to their healthy social development.
Highlights
• 1. Cross-sectional study of a large population of captive African elephant calves showed significant age-related changes in indicators of maternal independence and social development.
• 2. Interactions with other elephants of diverse age classes, including social touch and play, are highly relevant across early developmental stages and likely promote prosocial behavior and elephant welfare in captive settings.
Orienting to gaze-direction is widespread among animal species, but evidence for spontaneous use of gesture for direction is limited [1]. Remarkably, African elephants (Loxodonta africana) have been found able to follow human pointing, including subtle actions in which the contralateral hand is used, and in which the body silhouette is not broken [2,3]. The natural origin of this ability is puzzling, as the species is not reported to use trunk- or limb-gesture for showing directions [4]. One natural gesture, the ‘periscope-sniff’ presumed to be used to enhance olfactory sampling by an elephant in circumstances of alarm or curiosity [5], might also betray the elephant’s direction of focal attention. Here we investigate what information elephants gain from seeing periscope-sniff. When one elephant in a group gave a periscope-sniff, we recorded the location and orientation of the next periscope-sniff given. Elephants that could not see the first gesturer only gestured themselves if immediately adjacent to the first or closer to the presumed stimulus of interest. In contrast, elephants able to see the first signaller’s periscope-sniff were often a considerable distance behind it, further from the stimulus. Focusing on these cases, where making the periscope-sniff was apparently caused by seeing the first gesture, we found its orientation significantly matched the first, suggesting that direction information was gained from seeing the periscope-sniff. Elephants’ ability to use a conspecific’s periscope-sniff as if it were an ostensive pointing gesture enables them to react to the presence and location of potential dangers.
Animal vocalisations can signify diverse behavioural contexts, knowledge of which can be applied in bioacoustic monitoring programs. Australia’s endemic black cockatoos (Calyptorhynchus sp., family Cacatuidae) are highly vocal species that are threatened in many locations. In this study, we describe the nest‐associated vocal behaviours of two endangered subspecies of black cockatoo, the south‐eastern red‐tailed black cockatoo, C. banksii graptogyne and the Kangaroo Island glossy black cockatoo, C. lathami halmaturinus . Breeding success is limiting their recoveries and nest monitoring is challenging, but vocal recordings might provide valuable long‐term information hard to obtain otherwise. We recorded daily vocal activity at wild nests of both cockatoos using autonomous sound recorders. Combined with behavioural observations and video footage, we identified vocalisations characteristic of six behavioural contexts at nests: birds in flight, while perched, during begging (adult females), during courtship displays (adult males), when entering or sitting near to the nest hollow entrance (adult females), and from nestlings. Linear discriminant analysis on 12 acoustic measurements correctly classified 58.4% of calls of the red‐tailed black cockatoo (n = 907 calls from eight nests) and 62.9% of calls of the glossy black cockatoo (n = 1632 calls from 11 nests). In both subspecies, the female nest call and nestling calls are the most conspicuous vocal indicators of active nesting, and therefore should be considered for their bioacoustic potential. Other adult vocalisations indicate a range of behavioural contexts that could be informative for monitoring nesting behaviour, and its association to habitat features, in these endangered subspecies.
Quantitative assessments of the structure of vocalizations are a fundamental prerequisite to understand a species’ vocal communication system and, more broadly, the selective pressures shaping vocal repertoires. For example, to reduce ambiguity in signal interpretation in the absence of auxiliary visual cues, species in densely vegetated habitats should exhibit more discrete vocal signals than species in open habitats. To test this “ambiguity reduction hypothesis”, we conducted the first quantitative assessment of the rumble vocalizations of the forest elephant. Based on 686 forest elephant rumbles recorded with autonomous acoustic recording units at four sites across Central Africa, we used model-based cluster analyses paired with subsequent evaluation of cluster-discreteness and discriminant function analyses to quantify the structure of rumbles based on 23 source- and filter-related acoustic parameters. Model-based cluster analyses suggest that rumbles can be classified into five to eight types. Similar to previous findings in savannah elephants and contrary to the ambiguity reduction hypothesis, average silhouette coefficients below 0.34 indicated that these rumble types were highly intergraded. However, discriminant function analyses predicted rumble types with at least 75% accuracy whereby the location of the minimum fundamental frequency, middle slope and peak frequency contributed most to separation between types. In line with an increasing number of studies highlighting that a distinction between discrete and graded repertoires may have little biological significance, we propose that ambiguity reduction may take place through the evolution of perceptual and cognitive mechanisms, rather than acting on vocal production.
Southern Tanzania Elephant Program (STEP) has an ongoing elephant monitoring program in Ruaha National Park to collect long-term data on elephant ecology, behaviour, and demography. One key aim of our program is to understand seasonal patterns in elephant use of the ecosystem. Since February 2015, we have conducted over 100 vehicle transects (covering >10,000 km) to collect elephant sightings and dung density data along Ruaha's major rivers and across different habitats. We used Getis-Ord hotspot analysis to identify significant spatial clusters of elephant dung and elephant sightings along the transect network. We found that the Ruaha basin and the miombo-dominated area of the plateau were used year-round by elephants. The location of elephant hotspots varied between seasons and years and were potentially related to water and forage availability as well as social and risk factors. We found evidence of both spatial overlap and segregation between bulls and cow-calf groups.
Open access link til Nov 13th:
https://authors.elsevier.com/a/1XnGs15DJ~tY1P
Strategies for the conservation and management of many wild species requires an improved understanding of how population dynamics respond to changes in environmental conditions, including key drivers such as food availability. The development of mechanistic predictive models, in which the underlying processes of a system are modelled, enables a robust understanding of these demographic responses to dynamic environmental conditions. We present an individual-based energy budget model for a mega-herbivore, the African elephant (Loxodonta africana), which relates remotely measured changes in food availability to vital demographic rates of birth and mortality. Elephants require large spaces over which to roam in search of seasonal food, and thus are vulnerable to environmental changes which limit space use or alter food availability. The model is constructed using principles of physiological ecology; uncertain parameter values are calibrated using approximate Bayesian computation. The resulting model fits observed population dynamics data well. The model has critical value in being able to project elephant population size under future environmental conditions and is applicable to other mammalian herbivores with appropriate parameterisation.
We introduce a Special Section of The Journal of Wildlife Management (JWM) that contains 9 papers describing in theory and in practice a wide range of applications of resource selection statistics, several of which have not been previously published. There is an intense interest in and widespread use of resource selection statistics in the study of wildlife and habitat relationships. There is also debate over the proper application of these methods. We briefly describe the debate and the papers contained in the Special Section. We point out that resource selection statistics, when properly applied, can be a powerful tool in wildlife research.
We introduce a Special Section of The Journal of Wildlife Management (JWM) that contains 9 papers describing in theory and in practice a wide range of applications of resource selection statistics, several of which have not been previously published. There is an intense interest in and widespread use of resource selection statistics in the study of wildlife and habitat relationships. There is also debate over the proper application of these methods. We briefly describe the debate and the papers contained in the Special Section. We point out that resource selection statistics, when properly applied, can be a powerful tool in wildlife research.
2007. 272 pp. (Paperback). Price: US$ 16.95. ISBN-13: 978-1-57805. 'At least once in a lifetime', Schaller urges in this book, 'everyone should make a pilgrimage into the wilderness to dwell on its wonders and discover the idyll of a past now largely gone.' George B. Schaller, the legendary naturalist–explorer of our time, needs no introduction. Considered by many of us as the father of field biology, he is re-nowned for his ground-breaking studies on many charismatic species such as the African lion, Indian tiger, jaguar, snow leopard, mountain gorilla, Marco Polo sheep, chiru and giant panda. Schaller's credentials as a field biologist are im-maculate, and so are his writing skills. His works have been echoed in classic books such as National Book Award winner, The Serengeti Lion, The Year of the Gorilla, The Last Panda and many more. This book is an assortment of 19 such soul-nourishing short essays, inter-woven with his personal reflections on natural history and life itself, previously published in various magazines and books over the past five decade provid-ing a unique overview of his legendary career. The chapters are organized tidily into four continental sections. Beginning as a young biologist in the Arctic of the North America, Schaller takes us on an extraordinary journey to varied unique and wild places not travelled to by most, introducing us to the animals he studied and cherished, that many of us will never see in the wild 'Knowing such animals individually', he writes, 'one begins to view an area with a new intimacy and with a caring that turns into a special enchantment'. The charm of the book lies in his brazen love of the species he studies and his elegant way of describing them. His own photographs of field work, author himself and his family apart from the species he has observed and the places he has explored appear throughout the book, giving us a glimpse of the world he has lived. While reading the book, I could not resist the feeling of walking with him to those remote places he has described. Descriptions of the species and the land-scape are enhanced by the fact that Schaller is also a trained ethologist, and knows the way of recording minute and significant observations. He considers himself as 'a nineteenth-century natural-ist', who uses pen and photograph as potent weapons against human ignorance of the grace of nature, to reach people to conserve a species. Novel to this book are Schaller's introductions for each chapter, his present thoughts, which up-date information on the species, and their present conservation challenges. With a tap of spiritual aestheticism, occasionally dwelling on a kind of quest of under-standing nature, both the outer as well as his own true nature, Schaller writes, 'Af-ter all, the reasons for any quest dwell deep within us and are not always acces-sible even to introspection.' But then again it is not the story of a quest, but of a life's experience that the author lives intensely moment by moment. The initial chapters present the author as a pure field biologist in his early career but, as later essays show, he has broadened his outlook over the time to become an out-spoken proponent for conserving these wild animals and their habitats. The introduction part titled 'Of mar-vels and memories', itself comes out as marvellous portrait of the life, work and philosophy of the author. Speaking of his view on conservation Schaller writes, 'there is no final destination for conser-vation ...I have chosen a never ending path…so I strive to protect something that will outlive me.' He rightly points out that 'conservation problems are social and economic, not scientific… research is easy; Conservation most de-cidedly is not', appealing to biologists, especially to the ecologists to be commit-ted to science education, conservation and public outreach beyond their res-earch. He writes in the same chapter that today people speak of nature as 'natural resources' and he finds today's conserva-tion assembly lacking in heart, '... an appeal for conservation must reach the heart, not just the mind', because 'con-servation without moral values cannot sustain itself'. Defining a field biologist in 'Feral Biologist', he points out, 'patience becomes a more valuable com-modity than intellect…Indeed, a field biologist's greatest danger lies not in encounters with fierce creatures and treacherous terrain, but in being seduced by the comforts of civilization.' A feral biologist…he says is 'someone who suffers from cultural shock not when set-tling into a project but on returning home, he is a true feral biologist'. Schaller's literary talent, pooled with his zeal for getting to ground in the field, triumphs over many of the finest nature writings. 'Flowing towards me like a wall of dark brown lava', he remembers at Sheenjek river on Alaska's North Slope, when surrounded by the caribou herd. While observing capybaras in Argentina, he recalls '...As I lay looking up at the rodents, I felt like a strayed Lil-liputian among a colony of field mice.' Telling of his many futile efforts to catch the elusive jaguar to radio collar in Bra-zil's Pantanal, he reveals 'jaguars may even kill cows by crunching open their skulls, using a primitive force alien to lions and tigers'. In the Virunga Moun-tains he writes, '…felt a brief spasm of panic, for the gorillas had never behaved in this manner before', while he flees onto a tree when charged by D.J., a sil-verback mountain gorilla. In the Seren-geti, Schaller speaks of an anxious moonlit night, '…night with menacing snarls…the air with the odor of blood', with a pride of lionesses eating a zebra. '…their frosty eyes remind me of im-mense solitudes', he writes for elusive snow leopards which he studied in the Hindu Kush mountain. 'I was grateful for her curiosity and boldness…I would not have seen much of her without her con-sent', he writes in the same chapter, while watching a snow leopard eating her kill. The plain beauty and truth in his proses which appear throughout the book, totally floored me again and again. Other chapters describe studying the behaviour of the great blue heron, stalk-ing tigers in India, his hermit in the snow-laden land of the giant panda, wit-nessing vast herds of Mongolian gazelle and chiru, observing mating behaviour of
Re-introduced African elephant (Loxodonta africana Blumenbach) populations are growing at very high rates in many of southern Africa's reserves, have attained densities higher than previously thought possible and may be exhibiting irruptive growth. Active management of such populations is necessary to prevent the potentially negative effects on habitat and biodiversity that are associated with elephant overpopulation. One potentially feasible method of elephant management is immunocontraception, but very little is known about the long-term effectiveness of this method. Using demographic data from three South African elephant populations, we made model projections of the effects of contraception on population growth rates to determine whether contraception may be a feasible management tool for elephant. In comparison with noncontracepted populations, realistic reductions in population growth rate after 20 years of contraception were projected to be up to c. 64%, with 50% being a very feasible target. Through its ability to reduce population growth rates, immunocontraception should be an effective tool for preventing or minimizing irruption in elephants and, perhaps, other introduced ungulate species.