Social Interactions in Zoo-Housed Elephants: Factors Affecting Social Relationships

Male elephant management in AZA institutions: Current status and priorities for the future

Asian elephant (Elephas maximus) and African savanna elephant (Loxodonta africana) populations collectively managed by ex-situ facilities accredited by the Association of Zoos and Aquariums (AZA) face sustainability challenges. Among the priorities to strengthen animal wellbeing and population sustainability is male elephant management. We conducted a survey of AZA facilities currently housing male elephants to assess the status, challenges, and priorities in three areas of male elephant management: musth, socialization, and semen collection. Surveys were administered to elephant care teams at AZA-accredited institutions between November 2022 and February 2023, and we received responses from 34 institutions (91.9% of AZA-accredited facilities holding adult male elephants), housing 32 adult male Asians and 26 adult male Africans. Most facilities prioritized breeding and male socialization over musth management and semen collection (although most facilities acknowledged that all these efforts are important), citing leadership support and staffing as most important to achieve male management goals. Behaviors most commonly accompanying musth included reduced appetite, difficulty training or shifting, human-directed aggression, and interest in females. Musth timing was variable between males and facilities. Most males were well-socialized with females and/or other males, though elephant compatibility and facility design were limiting factors in managing socialization. Although 60.6% of facilities collected semen or were training for semen collection, very few male elephants could reliably provide viable semen samples, challenging assisted reproductive efforts that could bolster population sustainability in both species. Together, our results provide a better understanding of the state of male elephant management, offering specific areas deserving of research and development to enhance wellbeing and sustainability.

Hormonal variation and temporal dynamics of musth in Asian elephants (Elephas maximus) are associated with age, body condition and the social environment

The sustainability of endangered Asian elephants in human care is threatened in part by low breeding success and concerns over individual animal wellbeing. Male elephants have received less research attention compared to females, yet males deserve special consideration due to their unique reproductive biology (particularly the sexual state of "musth") and the complex interaction of physiological, environmental, and social pressures they face. We measured fecal androgen metabolites (FAMs), fecal glucocorticoid metabolites (FGMs), and fecal triiodothyronine metabolites (FT3s) collected weekly over approximately 12 months from 26 male Asian elephants housed in zoos across the US, hypothesizing that FAM, FGM, and FT3 concentrations would be associated with temporal correlates of musth and would vary further with intrinsic (musth status, age, body condition) and extrinsic (social environment) factors. The duration of each musth episode was positively associated with exposure to male conspecifics and negatively associated with body condition. Further, elevated FAM concentrations were associated with social exposure, age, and body condition, and FGM concentrations also varied with age and body condition. FT3 concentrations were not associated with any factor we measured. We also identified periods of lower FAM concentration than confirmed musth episodes (but still higher than baseline FAM concentrations) that we termed "elevated FAM episodes." The durations of these episodes were negatively correlated with exposure to other male elephants. Together, these results provide evidence that hormone profiles (including those that are predicted to change around musth) vary significantly between male Asian elephants in a way that may be attributed to intrinsic and extrinsic factors. Studies like these serve to enhance the sustainability of ex-situ populations by providing wildlife managers with information to enhance the health, welfare, and reproduction of threatened species like Asian elephants.

Dither: A unifying model of the effects of visitor numbers on zoo animal behavior

Interest in the impact of human presence on the behavior and well-being of zoo and aquarium animals is increasing. Previous work has conceptualized the presence of zoo visitors as having one of three impacts on the behavior of animals in zoos: positive, negative, or neutral. Research suggests the same species may exhibit all three responses under different conditions, calling into question whether the positive/negative/neutral framework is the most useful way of considering visitor impact on animal behavior. Here we present a model of visitor effects that unifies these three predictions. Our model suggests that zoo-goers may provide a "dither effect" for some animals living in zoos. We posit animals may show nonlinear behavioral responses over a range of visitor densities, effectively exhibiting changes in both comfortable and anxiety-like behaviors under different levels of human presence. We tested this model during two COVID-19 related closures at the San Francisco Zoo, studying seven species for evidence of nonlinear relationships between visitor numbers and animal behavior. Our results support the dither effect acting in several species observed.

Behaviour and Welfare Impacts of Releasing Elephants from Overnight Tethers: A Zimbabwean Case Study

Within the southern African elephant tourism industry, chaining or tethering elephants is still a relatively routine practice, despite the known negative impacts. Cited reasons for chaining include fear of aggressive interactions between elephants when handlers are absent, or a general increase in expression of aggressive behaviours (both to other elephants and to their human handlers). In Zimbabwe, concerns expressed include the danger of elephants escaping and entering human-inhabited areas. Four male semi-captive elephants at a Zimbabwe tourist facility were taken off overnight (~12 h) tethers and were placed in small pens (‘bomas’), approximate sizes from 110 m2 to 310 m2), as part of a strategy to improve elephant welfare. Behavioural data were collected from overnight videos from December 2019 to March 2020, between 18:00 to 06:00, using focal, instantaneous sampling (5-min interval). Data were collected for three nights at three time periods: (i) Tethered; (ii) approximately four weeks post-release; (iii) approximately eight weeks post-release. Behavioural change over these time points was analysed using general linear models with quasibinomial error structures. Behavioural changes indicative of improved welfare were observed following these management changes, and no significant increases in aggression were observed either between elephants, or towards their human handlers. Proportion of time engaging in lying rest was higher in the first month after release from tethering (mean ± SD, 50 ± 14%) than when elephants were tethered (20 ± 18%) (p < 0.05). Additionally, although not statistically significant, stereotypies were reduced when elephants were no longer tethered (4 ± 6% observations tethered compared to 2 ± 2% off tethers), and positive social behaviour also increased (1 ± 1% on tethers, 2 ± 2% off tethers), with the greatest improvements seen in the pair-housed elephants. To improve elephant welfare in southern African tourism facilities we strongly advocate that less restrictive management practices which enable greater choice and freedom of movement overnight are implemented.

Impacts of Socialization on Bull Asian Elephant (Elephas maximus) Stereotypical Behavior

There is a growing need for animal care institutions to house multiple bull elephants as the population increases due to transfers from private ownership and the births of male offspring in managed care. Elephants in North American, European, and Latin American zoos exhibit stereotypies—repetitive, fixed behaviors. Previous research demonstrated that housing Asian elephants alone increased stereotypic behavior. Therefore, for animals in managed care, social restriction can contribute to stereotypy and, by extension, reduce welfare. In this study, we examine how being alone affects stereotypic behavior by monitoring pacing and head-bobbing in individual bull Asian elephants at Denver Zoo when housed alone as well as with other bulls. Two young males arrived at Denver Zoo in September 2018 and joined an existing all-male group of three elephants that were previously socialized and housed together. From July 2018 to December 2019, we used instantaneous scan sampling to collect data on stereotypic behavior of focal bulls when they were housed alone and socially. The frequency of pacing and head-bobbing significantly decreased when the elephants were housed socially compared to when they were housed alone; these stereotypies were lower when elephants were housed with at least one other bull and were in close proximity to a conspecific. Additionally, pacing decreased as the proportion of affiliative behaviors increased, and the amount of agonistic behavior did not significantly affect stereotypic behavior. When housed alone, bulls in musth engaged in significantly more pacing behavior than when they were out of musth. Our results indicate that housing bull Asian elephants in all-male groups substantially improves their welfare by reducing stereotypies and provides a basis for future evidence-based management.

Monitoring Behaviour in African Elephants during Introduction into a New Group: Differences between Related and Unrelated Animals

Simple Summary

African elephants are highly social animals that perform a so-called Greeting Ceremony in the wild when meeting elephants they are familiar with but have not seen for a certain timespan. Until now, it has not been known whether zoo elephants also show this unique behaviour. Therefore, this study was designed around the reunifications of two mother–daughter pairs that had been separated for 2 and 12 years, and two unifications of unrelated elephants, as a comparison. First contact was conducted in a protected setting, i.e., there was a fence between the animals to prevent possible fighting. Signs of the Greeting Ceremony shown by the elephants, the distance they kept to the separating fence, and the time until the elephants’ trunks touched for the first time were observed. The results demonstrate that the related elephants showed all behavioural characteristic of the Greeting Ceremony, kept close to the fence, and touched trunks after only a few seconds, while elephants that were not familiar with each other did not show a full Greeting Ceremony, stayed further from the fence, and touched trunks for the first time only after several minutes upon meeting. This study testifies that zoo elephants show the same typical social behaviour known from wild elephants (namely the Greeting Ceremony) and, therefore, behave species-specific. It also confirms the strong family bonds of elephants and the cognitive abilities of elephants, specifically their long-term social memory.

Abstract

The introduction of elephants into new groups is necessary for breeding programmes. However, behavioural studies on the reactions of these animals at first encounters are missing. In the present study, female African elephants (Loxodonta africana) living in zoos were observed during unifications with unfamiliar elephants (introduction of two to one females and one to two females; n = 6) and reunifications with related elephants (two mother–daughter-pairs; n = 4) that were separated for 2 and 12 years, respectively. First encounters of the elephants were observed and recorded by scan sampling. The parameters measured were (a) signs of the characteristic Greeting Ceremony, (b) distance to the fence separating the elephants during first contact, and (c) time until trunks touched for the first time. The data were statistically analysed with SPSS. The results showed that related elephants performed a full Greeting Ceremony on reunifications. Unrelated elephants only expressed a minor greeting. During first encounters, related elephants predominantly showed affiliative behaviour (p = 0.001), whilst unrelated elephants expressed more agonistic behaviour (p = 0.001). The distance to the fence was significantly smaller for related elephants than for unrelated elephants (p = 0.038). first contact of trunks occurred on average after 3.00 s. in related elephants and 1026.25 s. in unrelated elephants. These findings indicate that related elephants recognise their kin after up to 12 years of separation, meet them with a full Greeting Ceremony during reunification, and seek contact to the related elephant, while unrelated elephants are hesitant during unifications with unfamiliar elephants and express more agonistic behaviour. The results testify that zoo elephants show the same species-specific social behaviour as their conspecifics in the wild. It also confirms the cognitive abilities of elephants and the significance of matrilines for breeding programmes.

Social Behaviour in Zoo Bachelor Groups: A Case Study of Related South American Fur Seals

Simple Summary

Appropriate management of social groups is one of the greatest challenges that face zoos and aquaria worldwide. All-male social groups provide an opportunity for facilities to house surplus males in groups which optimise their welfare whilst they are being retained for future use in breeding programmes. Here, we investigated social behaviour in a relatively poorly studied species, the South American fur seal (SAFS). Four individuals housed in a related group were studied over a 6-month period. The results showed that their social relationships changed over time, although the individuals always engaged in more positive than negative interactions. We recommend establishing baseline social behaviour profiles of individuals to enable long-term monitoring of SAFS social groups, as has been recommended in other species. This will enable enhanced understanding of South American fur seals and will contribute to the development of evidence-based social management guidelines for this species.

Abstract

Appropriate management of social groups is one of the greatest challenges that face zoos and aquaria worldwide. To facilitate breeding programmes, particularly in polygynous species, there is a need to house surplus males in bachelor groups, yet for pinnipeds, the social impact of this management strategy is unknown. The aim of this research was to enhance understanding of sociality in South American fur seals (SAFSs), with a particular focus on social dynamics in a related bachelor group, and consider implications for evidence-based management of this species in zoos. The subjects were four related male seals housed at Bristol Zoo Gardens. Social interaction and nearest neighbour data were collected between February and July 2019. Individuals engaged in both positive and negative social interactions. Positive interactions were more frequent than negative interactions, and no excessive negative interactions were observed. Temporal dynamics were observed in social relationships, and negative interactions did not increase with the onset of the breeding season. Reciprocity in dyadic relationships was variable across the study months, and nearest neighbours were not necessarily reflective of social partners. This research highlights the importance of longitudinal monitoring of social relationships and establishment of baseline social behaviour profiles to support evidence-based species management. We advocate that this research is extended, to further develop our understanding of SAFS social needs within zoo environments, to understand the differences between single-sex and mixed-sex groups and to identify the degree to which the extensive research conducted in other polygynous species (e.g., gorillas) is applicable in the social management of South American fur seals moving forwards.

A novel theory of Asian elephant high-frequency squeak production

BACKGROUND

Anatomical and cognitive adaptations to overcome morpho-mechanical limitations of laryngeal sound production, where body size and the related vocal apparatus dimensions determine the fundamental frequency, increase vocal diversity across taxa. Elephants flexibly use laryngeal and trunk-based vocalizations to form a repertoire ranging from infrasonic rumbles to higher-pitched trumpets. Moreover, they are among the few evolutionarily distantly related animals (humans, pinnipeds, cetaceans, birds) capable of imitating species-atypical sounds. Yet, their vocal plasticity has so far not been related to functions within their natural communicative system, in part because not all call types have been systematically studied. Here, we reveal how Asian elephants (Elephas maximus) produce species-specific squeaks (F0 300-2300 Hz) by using acoustic camera recordings to visualize sound emission and examining this alongside acoustic, behavioral, and morphological data across seven captive groups.

RESULTS

We found that squeaks were emitted through the closed mouth in synchrony with cheek depression and retraction of the labial angles. The simultaneous emission of squeaks with nasal snorts (biphonation) in one individual confirmed that squeak production was independent of nasal passage involvement and this implicated oral sound production. The squeaks' spectral structure is incongruent with laryngeal sound production and aerodynamic whistles, pointing to tissue vibration as the sound source. Anatomical considerations suggest that the longitudinal closed lips function as the vibrators. Acoustic and temporal parameters exhibit high intra- and inter-individual variability that enables individual but no call-subtype classification. Only 19 of 56 study subjects were recorded to squeak, mostly during alarming contexts and social arousal but some also on command.

CONCLUSION

Our results strongly suggest that Asian elephants force air from the small oral cavity through the tensed lips, inducing self-sustained lip vibration. Besides human brass players, lip buzzing is not described elsewhere in the animal kingdom. Given the complexity of the proposed mechanism, the surprising absence of squeaking in most of the unrelated subjects and the indication for volitional control, we hypothesize that squeak production involves social learning. Our study offers new insights into how vocal and cognitive flexibility enables mammals to overcome size-related limitations of laryngeal sound production. This flexibility enables Asian elephants to exploit a frequency range spanning seven octaves within their communicative system.

Insights into Activity of Zoo Housed Asian Elephants (Elephas maximus) during Periods of Limited Staff and Visitor Presence, a Focus on Resting Behaviour

Historically, behaviour of zoo housed species during hours of limited staff and visitor presence has been poorly studied, largely due to the lack of appropriate technology. Advances in digital monitoring equipment and facility design by European elephant holders has given researchers scope to accurately evaluate behaviour for this species over 24 hrs. Various behavioural indicators of welfare have now been identified for zoo housed elephants; however the relationship between resting behaviour and welfare experience has been an area highlighted to require additional research. Lying rest is a potential positive welfare indicator for this species, with studies suggesting that engagement in lying rest can be used to monitor both psychological and physiological wellbeing. Throughout this work we aim to give insights into the behaviour of individual Asian elephants at ZSL Whipsnade Zoo, specifically between the hours of 16:00 and 10:00. In addition to presenting the activity budgets of our study individuals during these times, we explore individual engagement in resting behaviour. Furthermore, we evaluate the social associations of our study group during rest. We provide evidence that unrelated individuals can form strong associations with conspecifics when resting and show that life history is a factor to consider when evaluating social compatibility between group members. Finally, we demonstrate the positive role that calves and juvenile individuals can play in facilitating meaningful associations between group members during rest. Our study highlights the importance of evaluating behaviour during understudied time periods in order to obtain a holistic view of individual welfare, further emphasising the importance of adopting an evidence-based approach to management for this species in zoos.

Koi (Cyprinus rubrofuscus) Seek Out Tactile Interaction with Humans: General Patterns and Individual Differences

The study of human-animal interactions has provided insights into the welfare of many species. To date, however, research has largely focused on human relationships with captive mammals, with relatively little exploration of interactions between humans and other vertebrates, despite non-mammals constituting the vast majority of animals currently living under human management. With this study, we aimed to address this gap in knowledge by investigating human-fish interactions at a community garden/aquaponics learning-center that is home to approximately 150 goldfish (Carassius auratus) and seven adult and two juvenile koi (Cyprinus rubrofuscus). After a habituation period (July-September 2019) during which time the fish were regularly provided with the opportunity to engage with the researcher's submerged hand, but were not forced to interact with the researcher, we collected video data on 10 non-consecutive study days during the month of October. This procedure produced 18~20-min interaction sessions, 10 during T1 (when the experimenter first arrived and the fish had not been fed) and eight during T2 (20-30 min after the fish had been fed to satiation; two sessions of which were lost due equipment malfunction). Interactions between the researcher and the seven adult koi were coded from video based on location (within reach, on the periphery, or out of reach from the researcher) and instances of physical, tactile interaction. Analyses revealed that overall, koi spent more time than expected within reach of the researcher during both T1 (p < 0.02) and T2 (p < 0.03). There were also substantial differences between individuals' overall propensity for being within-reach and engaging in physical interaction. These results show that koi will voluntarily interact with humans and that individual koi display unique and consistent patterns of interaction. By providing quantitative data to support anecdotal claims that such relationships exist around the world, this research contributes to the ongoing discoveries highlighting the profound dissonance between how humans think about and treat fish and who fish actually are, thereby emphasizing the necessity of stronger moral and legal protections for fishes.

Longitudinal Improvements in Zoo-Housed Elephant Welfare: A Case Study at ZSL Whipsnade Zoo

Simple Summary

Zoo elephant welfare has been the topic of much debate over the last two decades, with criticisms made regarding the husbandry and welfare of these species held in European and North American zoos. The aim of this study was to evidence the value of a species-specific behavioural monitoring programme and highlight the positive improvements in elephant welfare that were made in a single collection case study, by the comparison of behavioural activity budgets (time spent performing a particular behaviour) with previous published literature. This study identifies numerous indicators of positive welfare in our collection, including species-appropriate levels of feeding, low engagement in stereotypy (abnormal repetitive behaviour), and proportions of resting behaviour that are consistent with figures published from comparative zoo individuals. Additionally, we show that positive social associations exist between individuals in our study group, with low incidences of agonistic social behaviour and high engagement in positive social interactions. Finally, we acknowledge that improvements are required to further enhance elephant welfare in zoos and we have used the data collected throughout this research programme to adopt an evidence-based approach to the husbandry and management of Asian elephants at Zoological Society of London (ZSL) Whipsnade Zoo.

Abstract

Over the last two decades, criticisms were raised regarding the welfare experienced by elephants in European and North American zoos. Concerns regarding the welfare of zoo-housed elephants in the UK and Europe were consolidated in the publication of several key reports, and media interest peaked. Throughout this study we aim to outline the behavioural measures of welfare observed in the current group of Asian elephants (Elephas maximus) at Zoological Society of London (ZSL) Whipsnade Zoo, using key welfare indicators for this species and comparing them to previous published work. Following the instigation of a species-specific research programme, empirical behavioural data were available to quantify any developments in care and welfare. The collection of behavioural information revealed that individuals in our study group engage in low levels of stereotypic behaviour, have formed and maintain strong associations with one another and display a high proportion of engagement in lying rest. We outline that by applying simple, low-cost methods of behavioural data collection and analysis, it is possible to collect evidence that allows us to evaluate individual level welfare. This facilitates the adoption of an evidence-based approach to zoo management as well as demonstrating compliance with updated legislation for this species.

Reproductive performance of captive Asian elephants (Elephas maximus) in large tourist camps in Thailand

In Thailand, many elephants are used in tourism, with populations sustained by breeding of animals that are in captive habitats. Even though there are programs to promote breeding, there is not success in all camps. In this study, there was summarization of reproductive performance data of 407 elephants (150 males, 257 females) at seven tourist camps based on 4-21 years of breeding records. Age pyramid structures for elephants varied among camps. Reproductive rates averaged 21.6 ± 6.17% and varied among camps (2.8-45.0%). Based on parity, 77.4% of elephants were nulliparous, 8.2% produced one calf, and 14.3% were multiparous, with there being camp differences. There were 1.10 ± 0.46 (range, 0.03-3.55) births per year, with a total of 19.6 ± 9.3 (1-71) calves per camp. Age at first calving was 19.2 ± 1.1 years (range, 8-40 years), mean inter-birth interval was 4.4 ± 0.2 years (range, 1.8-7.9 years), and average gestation length was 653.9 ± 6.9 days (range, 578-743 days). Rates of abortions/stillbirths averaged 12.4% and ranged from 3.5%-66.7%. There were no obvious differences in management (e.g., number of males, estrous detection methods, work activities) that when evaluated explained the range in breeding success, although lack of male interest in females was a common problem. While informative and useful for designing future studies, results of this study indicate there is a lack of precise breeding records that makes it difficult to evaluate effects of management practices on reproductive performance of captive elephants in Thailand.

A preliminary study of mirror-induced self-directed behaviour on wildlife at the Royal Belum Rainforest Malaysia

Mirror-induced behaviour has been described as a cognitive ability of an animal to self-direct their image in front of the mirror. Most animals when exposed to a mirror responded with a social interactive behaviour such as aggressiveness, exploratory and repetitive behaviour. The objective of this study is to determine the mirror-induced self-directed behaviour on wildlife at the Royal Belum Rainforest, Malaysia. Wildlife species at the Royal Belum Rainforest were identified using a camera traps from pre-determined natural saltlick locations. Acrylic mirrors with steel frame were placed facing the two saltlicks (Sira Batu and Sira Tanah) and the camera traps with motion-detecting infrared sensor were placed at strategically hidden spot. The behavioural data of the animal response to the mirror were analysed using an ethogram procedure. Results showed that barking deer was the species showing the highest interaction in front of the mirror. Elephants displayed self-directed response through inspecting behaviour via usage of their trunk and legs while interacting to the mirror. Interestingly, the Malayan tapir showed startled behaviour during their interaction with the mirror. However, the absence of interactive behaviour of the Malayan tiger signalled a likelihood of a decreased social response behaviour. These results suggested that the ability to self-directed in front of the mirror is most likely related to the new approach to study the neural mechanism and its level of stimulus response in wildlife. In conclusion, research on mirror-induced self-directed behaviour in wildlife will have profound implications in understanding the cognitive ability of wildlife as an effort to enhance the management strategies and conservation.

Welfare Assessment and Activities of Captive Elephants in Thailand

Thailand is the epicenter of elephant tourism and visiting an elephant camp is a popular activity according to the Tourist Authority of Thailand. However, the welfare of these elephants has been questioned by animal activist groups, international tour operators, and the public. Conclusions that the vast majority of captive elephants are abused often are based on anecdotal evidence and not solid science. So, it is difficult to tease apart emotion, opinion, and fact with regard to what practices are good or bad for elephant welfare. The aim of this paper was to: 1) describe the unique status of captive elephants in Thailand and associated regulations, 2) summarize current issues and challenges facing elephant tourism, 3) review studies conducted on welfare of tourist elephants in Thailand, and 4) offer recommendations for how elephants can be properly cared for under captive conditions in tourist camps. We conclude there are many ways to manage these elephants, and that not all tourist activities are bad for welfare. However, it is essential they be managed in a way that meets physical, physiological and psychological needs, and that management decisions are based on objective data.

Understanding Temporal Social Dynamics in Zoo Animal Management: An Elephant Case Study

Zoo animal management procedures which lead to changes to social groups can cause disruption in social hierarchies and the temporary breakdown of social relationships. Animals have different roles in social networks. Understanding individual positions in social networks is important for effective management and ensuring positive welfare for all animals. Using elephants as a case study, the aim of this research was to investigate temporal social dynamics in zoo animals. Behavioural data were collected between January 2016 and February 2017 from 10 African and 22 Asian elephants housed at seven zoos and safari parks in the UK and Ireland. Social interactions were defined as positive physical, positive non-physical, negative physical or negative non-physical. Social network analysis explored social relationships including the fluidity of networks over time and dyadic reciprocity. Social interaction networks were found to be fluid but did not follow a seasonal pattern. Positive interaction networks tended to include the entire social group whereas negative interactions were restricted to specific individuals. Unbalanced ties were observed within dyads, suggesting potential inequalities in relationships. This could impact on individual experiences and welfare. This research highlights subtle temporal dynamics in zoo elephants with the potential for species-level differences. Similar temporal dynamics may also be present in other socially housed zoo species. This research thus provides evidence for the importance of understanding the social networks of zoo animals over longer periods of time. Understanding social networks enables pro-active and evidence-based management approaches. Further research should seek to identify the minimum sampling efforts for social networks in a range of species, to enable the implementation of regular monitoring of social networks and thus improve the welfare of social species under human care.