Social interaction analysis in captive orcas (Orcinus orca)

The management of socially complex species in captivity is challenging. Research on their social behavior improves our understanding of interactions in captive animals and captive‐group management. We conducted a detailed analysis of social relationships shown by the orcas kept at Loro Parque zoo and their tendency to reconcile after aggressive episodes. Affiliative interactions were the most frequent social activities compared to agonistic or sexual interactions. Within affiliative behaviors, we documented the pattern “gentle tongue bite”, where an animal touches the other's tongue with his teeth but does not bite it. Affiliative interactions between a specific pair of orcas occurred significantly more often than expected by chance, and together with low levels of agonistic interactions, indicated particular affinity between some individuals. The most frequently observed low‐level agonistic relationship was that of the two older males (Tekoa–Keto); however, they also showed frequent sexual and affiliative interactions. Sexual‐like behaviors (pursuit, mount, and penis between males) were found in both sexes. Finally, the observed corrected conciliatory tendency (31.57%) was within the range described for other primate and cetacean species. This study provides a systematic way to assess social interactions as well as conflict management strategies in cetaceans housed in zoos and zoo‐like facilities and may help to improve animal welfare and management of animals in controlled environments.     

Social and reproductive behaviour of critically endangered northern white rhinoceros in a zoological garden

Northern and southern white rhinos have poor reproduction in captivity and social interactions between them, especially increased agonistic behaviour, are believed to be one of the possible reasons. Northern white rhino is currently on the brink of extinction with less than ten animals surviving. We studied the social behaviour of northern white rhinos in zoological garden and investigated the effects of separation of the oldest, wild-born female from the herd on the social behaviour of other group members. After the separation, the numbers of agonistic and the play interactions between the animals significantly increased, no change was found in cohesive behaviour. Our results suggest that a composition of white rhino groups has a significant influence on social interactions between the animals and that better knowledge of proper composition of their groups in captivity in terms of age, sex and wild or zoo origin might improve animals’ well-being and also increase a chance for reproduction.     

Early play may predict later dominance relationships in yellow-bellied marmots (Marmota flaviventris)

Play has been defined as apparently functionless behaviour, yet since play is costly, models of adaptive evolution predict that it should have some beneficial function (or functions) that outweigh its costs. We provide strong evidence for a long-standing, but poorly supported hypothesis: that early social play is practice for later dominance relationships. We calculated the relative dominance rank by observing the directional outcome of playful interactions in juvenile and yearling yellow-bellied marmots (Marmota flaviventris) and found that these rank relationships were correlated with later dominance ranks calculated from agonistic interactions, however, the strength of this relationship attenuated over time. While play may have multiple functions, one of them may be to establish later dominance relationships in a minimally costly way.     

Hierarchy,kinship and social interaction among Japanese monkeys (Macaca fuscata)

The study reports the relationship between hierarchy, genetic relatedness and social interaction in captive Japanese macaques. Grooming and proximity were found to be positively related to both dominance rank and degrees of relatedness. Ranks also positively correlated with threats while no relationship was observed between genetic relationships and agonistic interactions. The removal of a-male tightened the male hierarchy while the female hierarchy became relatively loose. Affiliative behaviour became more correlated with ranks than degrees of genetic relatedness. In the absence of α-male, the next dominant male avoided involvement in either agonistic or afliliative interactions with reintroduced animals and group females.     

Inter-individual relationships in proboscis monkeys: a preliminary comparison with other non-human primates

This is the first report on inter-individual relationships within a one-male group of proboscis monkeys (Nasalis larvatus) based on detailed identification of individuals. From May 2005 to 2006, focal and ad libitum data of agonistic and grooming behaviour were collected in a forest along the Menanggul River, Sabah, Malaysia. During the study period, we collected over 1,968 h of focal data on the adult male and 1,539 h of focal data on the six females. Their social interactions, including agonistic and grooming behaviour, appeared to follow typical patterns reported for other colobines: the incidence of social interaction within groups is low. Of 39 agonistic events, 26 were displacement from sleeping places along the river, 6 were the α male threatening other monkeys to mediate quarrels between females and between females and juveniles, and 7 were displacement from feeding places. Although the agonistic behaviour matrix based on the 33 intra-group agonistic events (excluding events between adults and juveniles and between adults and infants) was indicative of non-significant linearity, there were some specific dominated individuals within the group of proboscis monkeys. Nonetheless, grooming behaviour among adult females within a group were not affected by the dominance hierarchy. This study also conducted initial comparisons of grooming patterns among proboscis monkeys and other primate species. On the basis of comparison of their grooming networks, similar grooming patterns among both-sex-disperse and male-philopatric/female-disperse species were detected. Because adult females in these species migrate to groups repeatedly, it may be difficult to establish the firm grooming exchange relationship for particular individuals within groups, unlike in female-philopatric/male-disperse species. However, grooming distribution patterns within groups among primate species were difficult to explain solely on the basis of their dispersal patterns. Newly immigrated females in some species including proboscis monkeys are eager to have social interactions with senior group members to improve their social position.     

Dominance hierarchy and social relationships in a group of Captive black-and-white snub-nosed monkeys (Rhinopithecus bieti)

Different types of dominance hierarchies reflect different social relationships in primates. In this study, we clarified the hierarchy and social relationships in a one-male unit of captive Rhinopithecus bieti observed between August 1998 and March 1999. Mean frequency of agonistic behaviour among adult females was 0.13 interactions per hour. Adult females exhibited a linear hierarchy with a reversal of 10.9%, indicating an unstable relationship; therefore, R. bieti appears to be a relaxed/tolerant species. The lack of a relationship between the agonistic ratio of the adult male towards adult females and their ranks indicated that males did not show increased aggression towards low-ranking females. Differentiated female affiliative relationships were loosely formed in terms of the male, and to some extent influenced by female estrus, implying that relationships between the male and females is influenced by estrus and not rank alone. A positive correlation between the agonistic ratio of adult females and their ranks showed that the degree to which one female negatively impacted others decreased with reduction in rank. Similarly, a positive correlation between the agonistic ratio of females and differences in rank suggests that a female had fewer negative effects on closely ranked individuals than distantly ranked ones. These data indicate that rank may influence relationships between females. A steeper slope of regression between the agonistic ratio and inter-female rank differences indicated that the extent of the power difference in high-ranking females exerting negative effects on low-ranking ones was larger during the mating season than the birth season, suggesting that rank may influence the mating success of females.     

Social behaviour and heart rate in tammar wallabies (Macropodidae: Macropus eugenii)

In an enclosed group of tammar wallabies the behaviour of all individuals and the heart rate (HR) of three males were recorded simultaneously. The social structure was characterized by the dominance relationships between the males and the sexual preference of all males for the oldest female. During non-oestrus, dominance was obvious when a male intervened terminating the sexual behaviour of a subdominant one. The relatively low amount of agonistic behaviour between the males is assumed to be due to the clear dominance relationships. Locomotion as well as sexual and agonistic behaviour were accompanied by an acceleration of HR. The HR pattern depended on the intensity of the behaviour, its duration and the animal's identity. Commonly performed sexual behaviour and approach/retreat encounters gave rise to HR values not different from HR values during locomotor activity without interactive components. Social events that occurred infrequently—like fights, and the mating of an oestrous female—were accompanied by strong accelerations of HR indicating high cardiac effort. The mild cardiac activity during common social encounters is consistent with a strategy of maximizing energy conservation. HR patterns during specific behaviour could not entirely be accounted for by the energetic costs of activity. Spreading the forelimbs in response to specific stimuli—like the fly-over of raptors—was indicative of a strong HR response even if the animal was motionless. During specific social encounters like the sexual behaviour of the alpha-male following an intervention—HR responses revealed that arousal might exceed motor activity in affecting HR. Individual differences of these HR responses are attributed to the age, experience and social status of a male.     

Reciprocity and communication of partner quality

In a cooperative exchange, the size of a partner''s contribution is likely to depend both on the partner''s ability to supply help and on the partner''s need for help in return. Referring to such needs and abilities as aspects of partner quality, it follows that variation in the amount of help offered in a relationship could transmit information about partner quality. A plausible behaviour might then be to vary the investment in a partner according to available information about partner quality and to invest little in a partner who offers little in return. Thus, regulation of a relationship through communication of partner quality would tend to follow the principle of reciprocity. In an analysis of an iterated game where players have private information about their needs and abilities, I verify this possibility by describing an evolutionarily stable state space strategy, referred to as ''state-dependent reciprocity'', entailing communication of partner quality. Although the evolution of cooperation has been studied in great detail, there has been no previous analysis of communication of needs and abilities in a relationship. It may well be that such communication is of major importance for the evolution of cooperative behaviour in nature.     

Agonistic Support in Juvenile Japanese Macaques: Cognitive and Functional Implications

Agonistic support is generally considered a classical example of altruistic behaviour. It plays a critical role in the process of rank acquisition. This study investigates agonistic coalitions involving juvenile Japanese macaques (Macaca fuscata) living in a large captive group. Kinship was a good predictor of agonistic support received by juvenile macaques. Kinship also had a significant, though weaker, influence on agonistic support given by juvenile macaques. The latter was strongly influenced by the prospective rank of the individual against which the coalition was directed, i.e. by the rank relationship between the target of the coalition and the juvenile’s mother. Juvenile macaques intervened aggressively more against prospectively subordinate individuals than against prospectively dominant individuals. These results imply agonistic support is not necessarily altruistic, and support the hypothesis that primates may understand the rank relationship that exist among their group mates, i.e. that they are aware of third‐party social relationships. They also suggest that selective pressures associated with the process of rank acquisition may have favoured the evolution of higher cognitive abilities.     

Retreat Space and Human Visitor Density Moderate Undesirable Behavior in Petting Zoo Animals

This study focused on the relationship between nonhuman animal behavior and environment-specifically, between the undesirable behavior exhibited by domestic petting zoo animals in the presence of humans and the spatial design of the petting zoo environment. A spatial feature of a petting zoo referred to as a retreat space was manipulated so that it affected the animals' opportunity for individual control over interaction with humans. Three conditions were tested: no retreat space, semi-retreat space, and a full-retreat space. The subjects of this study were 5 African pygmy goats (Capra hircus) and 2 Romanov sheep (Ovis aries). Investigators used a focal sampling technique to analyze approximately 27 hr of behavioral data collected. The data were analyzed using multiple linear regression methods. The findings suggest that the full-retreat design beneficially moderated both sheep and goat behavior: Undesirable behaviors were lowest in the full-retreat condition. This study provides information that may improve human-animal interactions in a petting zoo setting and may increase animal well-being through exhibit design and management techniques.     

Functional aspects of reconciliation among captive long-tailed macaques (Macaca fascicularis)

After an agonistic conflict between two animals, they may exchange affiliative social contacts. The function of this reconciliation behavior is thought to be the repair of the social relationship between the two opponents. We examined the hypothesis that reconciliation is socially effective because it may also lead to a reduction of the victim's acute stress. Reconciliation was studied in a well-established captive group of long-tailed macaques (Macaca fascicularis). The behavior of the victim in a 10 min period after the end of an agonistic interaction was recorded and compared with that of a control observation made on the same animal the next day. The tendency to reconcile was elevated above control levels only during the first 3 min. Reconciliation led to a fast reduction in scratching rates and to a decrease of the reoccurrence of aggression received. Losers took the initiative to reconcile more than expected. Dominants granted reconciliation depending on their relatedness with the victims and on the quality of the relationship with them. After those interactions in which contra-aggression and no clear submission occurred, the reconciliation rate was remarkably high. These results suggest that reconciliation can be an effective means to reduce the victim's acute stress and that its function in repairing social relationships can partly be mediated by its physiological effects. The intimate relation between the quality of the social relationship and the conciliatory tendency can be extrapolated to explain interspecific variation.     

Spectral call features provide information about the aggression level of greater mouse-eared bats (Myotis myotis) during agonistic interactions

Bats rely heavily on acoustic signals in order to communicate with each other in a variety of social contexts. Among those, agonistic interactions and accompanying vocalizations have received comparatively little study. Here, we studied the communicational behaviour between male greater mouse-eared bats (Myotis myotis) during agonistic encounters. Two randomly paired adult males were placed in a box that allowed us to record video and sound synchronously. We describe their vocal repertoire and compare the acoustic structure of vocalizations between two aggression levels, which we quantified via the bats’ behaviour. By inspecting thirty, one-minute long encounters, we identified a rich variety of social calls that can be described as two basic call types: echolocation-like, low-frequency sweeps and long, broadband squawks. Squawks, the most common vocalization, were often noisy, i.e. exhibited a chaotic spectral structure. We further provide evidence for individual signatures and the presence of nonlinear phenomena in this species’ vocal repertoire. As the usage and acoustic structure of vocalizations is known to encode the internal state of the caller, we had predicted that the spectral structure of squawks would be affected by the caller’s aggression level. Confirming our hypothesis, we found that increased aggression positively correlated with an increase in call frequency and tonality. We hypothesize that the extreme spectral variability between and within squawks can be explained by small fluctuations in vocal control parameters (e.g. subglottal pressure) that are caused by the elevated arousal, which is in turn influenced by the aggression level.     

Keeper-Animal Interactions: Differences between the Behaviour of Zoo Animals Affect Stockmanship

Stockmanship is a term used to describe the management of animals with a good stockperson someone who does this in a in a safe, effective, and low-stress manner for both the stock-keeper and animals involved. Although impacts of unfamiliar zoo visitors on animal behaviour have been extensively studied, the impact of stockmanship i.e familiar zoo keepers is a new area of research; which could reveal significant ramifications for zoo animal behaviour and welfare. It is likely that different relationships are formed dependant on the unique keeper-animal dyad (human-animal interaction, HAI). The aims of this study were to (1) investigate if unique keeper-animal dyads were formed in zoos, (2) determine whether keepers differed in their interactions towards animals regarding their attitude, animal knowledge and experience and (3) explore what factors affect keeper-animal dyads and ultimately influence animal behaviour and welfare. Eight black rhinoceros (Diceros bicornis), eleven Chapman’s zebra (Equus burchellii), and twelve Sulawesi crested black macaques (Macaca nigra) were studied in 6 zoos across the UK and USA. Subtle cues and commands directed by keepers towards animals were identified. The animals latency to respond and the respective behavioural response (cue-response) was recorded per keeper-animal dyad (n = 93). A questionnaire was constructed following a five-point Likert Scale design to record keeper demographic information and assess the job satisfaction of keepers, their attitude towards the animals and their perceived relationship with them. There was a significant difference in the animals’ latency to appropriately respond after cues and commands from different keepers, indicating unique keeper-animal dyads were formed. Stockmanship style was also different between keepers; two main components contributed equally towards this: “attitude towards the animals” and “knowledge and experience of the animals”. In this novel study, data demonstrated unique dyads were formed between keepers and zoo animals, which influenced animal behaviour.     

Similarities and differences in activities and agonistic behavior of male Eastern grey kangaroos (Macropus giganteus) in captivity and the wild

The behavior of free-ranging and captive Eastern grey kangaroos Macropus giganteus, was observed by the same observers, with similar methods and under similar vegetational/climatic conditions in a 4.2-ha enclosure at Neuwied Zoo, Germany and at Grampians National Park, Victoria, Australia. Data were collected from a zoo group of 56 animals and a free-ranging mob of 50 to 60 animals. Males were individually identified and observed: 3 large males, 9 medium males, and 10 small males in the zoo, and 8 large, 9 medium, and approximately 10 small males in the National Park were present. Activities in both situations were very similarly distributed: Feed took up less time in the zoo, resting was almost similar in both situations, alert behavior was significantly different for small and medium males, locomotor activities were similar in large males and females, autogrooming occurred significantly more in the zoo only for females. Frequencies of social interactions were slightly greater for large males and females in the zoo. Agonistic behavior in males was more frequent in the zoo situation, except for ritualized fights. Sequences of agonistic behavior were more predictable in the zoo. No differences in escalation tendencies toward potentially injurious fighting could be found. Zoo Biol 19:529-539, 2000. Copyright 2000 Wiley-Liss, Inc.     

Development of Social Behaviour in Four Litters of Dogs (Canis familiaris)

The development of social behaviour in 4 litters of dogs was observed without interfering with the puppies from birth to 8 weeks of age. Direct and continuous observation was combined with video recording. Three of the litters were observed during one session of 2 h once a week, and the fourth litter during one session of 40 min twice a week. Social interactions were divided into 1) investigation of litter mates (licking, sniffing or investigating orally), 2) social play, 3) and interactions in which agonistic elements (dominance postures, threats, bites or submission) were displayed. The different forms of social interactions appeared for the first time when the puppies were between 14 and 21 days of age. Social investigation appeared first and was followed by play and agonistic interactions. From week 5, differences between the puppies in the tendency to initiate social play and agonistic interactions emerged. Generally, within the litters individual differences were consistent over weeks 6-8 (positive correlations between weeks), whereas the tendency in the puppies during these weeks were negatively correlated with those of week 3 (play) or weeks 3 and 4 (agonistic interactions), indicating a rebound effect for both play and agonistic behaviour. No significant correlations, however, were found for social investigation. More often than expected males played or engaged in agonistic with other males, whereas these behaviours occurred less often than expected between females. Both males and females, however, preferred male partners for agonistic interactions. No sex differences were found in the direction of social investigation. Agonistic behaviour was often responded to by play and play was often responded to by agonistic behaviour, and the results indicated that before 8 weeks of age differences in social behaviour between the puppies were already established.     

Exposure to perceived male rivals raises men's testosterone on fertile relative to nonfertile days of their partner's ovulatory cycle

The challenge hypothesis posits that male testosterone levels increase in the presence of fertile females to facilitate mating and increase further in the presence of male rivals to facilitate male–male competition. This hypothesis has been supported in a number of nonhuman animal species. We conducted an experiment to test the challenge hypothesis in men. Thirty-four men were randomly assigned to view high-competitive or low-competitive male rivals at high and low fertility within their partner's ovulatory cycle (confirmed by luteinizing hormone tests). Testosterone was measured upon arrival to the lab and before and after the manipulation. Based on the challenge hypothesis, we predicted that a) men's baseline testosterone would be higher at high relative to low fertility within their partner's cycle, and b) men's testosterone would be higher in response to high-competitive rivals, but not in response to low-competitive rivals, at high relative to low fertility within their partner's cycle. Contrary to the first prediction, men's baseline testosterone levels did not differ across high and low fertility. However, consistent with the second prediction, men exposed to high-competitive rivals showed significantly higher post-test testosterone levels at high relative to low fertility, controlling for pre-test testosterone levels. Men exposed to low-competitive rivals showed no such pattern (though the fertility by competition condition interaction fell short of statistical significance). This preliminary support for the challenge hypothesis in men builds on a growing empirical literature suggesting that men possess mating adaptations sensitive to fertility cues emitted by their female partners.     

‘Separating the wheat from the chaff’: A novel food processing technique in captive gorillas (Gorilla g. gorilla)

Observation of a novel food processing technique is reported for captive zoo gorillas (Gorilla g. gorilla). It is similar in function to that of Japanese macaques' wheat placer mining behaviour and consists of puffing/blowing air with the mouth onto a mixture of oat grains and chaff in order to separate out the oat grains. Three females in two of four groups regularly use this behaviour. Other individuals in these groups or individuals of the two other groups in the same zoo do not use it. However, a very similar behaviour has been observed in three other individuals in a gorilla group of another zoo. The existence of this technique in spatially separated groups implies that multiple individuals have invented it for themselves. The possible role of social transmission is still to be investigated.     

The gap in technology for visitor experience in a zoo: A case study in Indonesia

Technology has routinely been used in zoos to enhance the visitor experience, for public education and for conservation awareness. However, studies into technology-aided exhibits in zoos have thus far been limited to zoos in western society. This article reports on an Indonesian zoo deploying new technology in its exhibits and how visitors interacted with these exhibits. A case study guided both an investigation of the visitors' technology usage of zoo exhibits and zoo implementation of technological processes. Interviews with visitors, zoo staff, and managers were conducted and analyzed and these were supplemented with on-site observations. The results indicated that the majority of zoo visitors did not use the technological applications provided by the zoo. In addition, there was found to be a significant lack of staff engagement in the consultation, design, implementation, and maintenance of the technology. Correlations were found between visitors' level of technology usage, their reading of signage, their day-to-day technology usage, and their conservation knowledge. The findings suggest that an understanding of visitor' behavior, active staff engagement in the development and implementation of new technology, in addition to emotion-inducing interpretation, and purposefully guided interactions, could increase the use of technology at a zoo and thus enhance positive visitor engagement, ultimately resulting in heightened educational as well as conservational outcomes.     

It's the attention that counts: interpersonal attention fosters intimacy and social exchange

Human friendship poses an evolutionary puzzle, since people behave more generously toward their friends than the tit-for-tat strategy stipulates. A possible explanation is that people selectively behave in a generous manner toward their true friends, but not toward fair-weather friends. Social psychological studies have suggested that people use a partner's attentiveness toward them as a cue to distinguish these two types of friends. Accordingly, it was hypothesized that people would increase their intimacy with a partner who was attentive to them. This hypothesis was tested by disentangling the frequent confounding between a partner's attention and the benefits provided by the attentive partner in two scenario experiments (studies 1a and 1b) and three laboratory experiments (studies 2a to 2c). In study 1, a partner's attentiveness was manipulated independently of the benefit provided by the partner. In study 2, the partner's attention was experimentally dissociated from any potential benefit. These studies consistently showed that the participants increased their intimacy with a partner when they received attention from the partner. This result implies that models of the evolution of friendship must incorporate information exchange regarding the valuation of the relationship, as well as the exchange of fitness-related costs and benefits.