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.     

Cognitive research in zoo-housed chimpanzees: influence of personality and impact on welfare

We monitored chimpanzee welfare during the introduction of on-exhibit cognitive research training and testing, as measured by behavior and interest in such training, and related individual variation to personality assessments. We observed 11 chimpanzees (six males; five females) over a 16-month period and compared their behavior across three conditions: (1) Baseline (nontraining/research situations) and (2) an on-going, off-exhibit program of Husbandry Training and (3) Research Pod Activities, on-exhibit, group training for cognitive testing. There was considerable individual variation in their interest levels during research sessions; females and those scoring higher for Openness were present more frequently (including those who actively participated and those who observed others participating), but interest did not vary in relation to rates of self-directed behaviors (SDBs), rank, or the level of social disruptions within the group (i.e. large-scale displays or fights). The frequency of SDBs was predicted by the Neuroticism personality factor, but did not differ across baseline and training contexts, indicating that these activities do not negatively impact welfare. We also explored vigilance as an indicator of social uncertainty, but social monitoring did not differ in relation to either social context or rank. Finally, we explored how the specific characteristics of the research context impacted on SDBs; namely, social context, reward contingency, and visual access to keepers. SDBs increased only when visual access to keepers was restricted, suggesting that visual contact reduced uncertainty in novel training contexts. Overall, the introduction of a cognitive research program did not compromise welfare, and the chimpanzees' repeated interest and willingness to participate suggests that the research was enriching.     

Comparison of confined mandrill (Mandrillus sphinx) behavior in traditional and “ecologically representative” exhibits

Behavior in a confined group of mandrills (Mandrillus sphinx) was compared before and after their move from a traditional, all indoor exhibit to an indoor/outdoor facility. The outdoor exhibit was designed to represent as well as is possible important features of the mandrills' forest habitat. We predicted that activity budgets in the outdoor exhibit would more closely resemble those of wild African Cercopithecines, specifically that time spent in forage/feed, locomotion, and social behavior would increase and time spent stationary would decrease. Time spent in forage/feed, locomotion, and stationary did change, as expected. However, there was a small significant decrease in some social behaviors. Differences in proximate environmental contingencies may explain the behavioral changes observed: feeding/foraging opportunities throughout the time on exhibit; increased social refuges; modest increase in facility size; and significantly increased environmental complexity and novelty. Our results are discussed within the context of data obtained from mandrills and baboons observed along a theoretical continuum between confined and free‐ranging environments. This analysis supports what others have suggested: that primate well‐being is not so much a function of confinement as of the presence of relevant incentives to engage in species‐appropriate behavior. Zoo Biol 18:163–176, 1999. © 1999 Wiley‐Liss, Inc.     

Dynamics of Male–Female Multimodal Signaling Behavior across the Estrous Cycle in Giant Pandas (Ailuropoda melanoleuca)

Giant panda courtship behavior includes multimodal signaling assemblages consisting of olfactory, vocal, and postural elements. While signaling is generally conspicuous, successful copulation is inconsistently achieved in captivity, even when female behavioral and physiological data indicate that ovulation is imminent. We set out to characterize these complex patterns of social behavior by observing interactions between 26 unique pairs of giant pandas housed in adjoining pens throughout the females' reproductive cycle. We categorized social behaviors from a transactional perspective and examined social exchanges via analyses of the relative frequency of social behaviors, and via the sequential relationship between male and female social behavior. From non‐estrus to peak‐estrus, we found that the relative frequency of female affiliative and sexual behavior increased and that the relative frequency of ambivalent and aggressive behavior decreased. Male behavior was fairly constant, except for sexual behavior, which increased during peak‐estrus, when it was facilitated by female sexual behavior. Sequential analysis of social interactions showed that preceding behavior had a significant influence over the other panda's response behavior primarily during peak‐estrus, suggesting that pandas are most responsive to conspecific signaling during the peri‐ovulatory period. However, behavioral momentum was a dominant feature of the intra‐individual transitions. Females maintained sexual, ambivalent, and neutral behavior during interactions significantly more than would be expected by chance, with male behavior bearing little influence once the behavior was initiated. A similar pattern was also observed in males, who maintained affiliative, interested, and neutral behaviors. Overall, our data suggest that the multimodal signals used by giant pandas during courtship do not consistently evoke a discrete, immediate response from receivers. Instead, signals appear to advertise reproductive condition and influence potential mates over longer timeframes, suggesting the potential tonic role of communication.     

Differences in Titi Monkey (Callicebus cupreus) Social Bonds Affect Arousal,Affiliation, and Response to Reward

Titi monkeys (Callicebus cupreus) are a monogamous, New World primate. Adult pair‐mates form a bidirectional social bond and offspring form a selective unidirectional bond to their father. Some of the neurobiology involved in social bonds and maternal behavior is similar to the neural circuitry involved in nonsocial reward. Due to these overlapping mechanisms, social states may affect responses to external rewarding stimuli. We sought to determine whether having a social attachment, and/or being in the presence of that attachment figure, can affect an individual's response to a rewarding stimulus. In addition, we compared affiliative bonds between pair‐mates to those between offspring and fathers. Eighteen adult male titi monkeys were either living alone (Lone), with a female pair‐mate (Paired), or with the natal group (Natal; N = 6/condition). Each individual went through eight 30‐min preference tests for a sweet substance, Tang. For Paired and Natal males, half of the test sessions were with their attachment figure and half were alone. Lone males were always tested alone. Preference scores for Tang, time spent drinking, affiliative, and arousal behaviors were measured. Paired and Natal males emitted significantly more isolation peeps and locomoted more when tested alone compared to when tested with their attachment figure, and paired males engaged in more affiliative behavior than Natal males. Lone males engaged in significantly more behaviors indicative of behavioral arousal such as locomotion and piloerection compared to Paired and Natal males. Finally, Paired males drank significantly more Tang and had a significantly greater preference for Tang compared to Lone and Natal males. These results indicate that offspring undergo a behavioral separation response upon separation from their father that persists into adulthood, Lone males are more behaviorally reactive, and that living with an attachment figure and the type of attachment relationship result in different responses to a rewarding sweet stimulus. Am. J. Primatol. 74:758‐769, 2012. © 2012 Wiley Periodicals, Inc.     

Sociability development in mice with cell‐specific deletion of the NMDA receptor NR1 subunit gene

Social affiliative behavior is an important component of everyday life in many species and is likely to be disrupted in disabling ways in various neurodevelopmental and neuropsychiatric disorders. Therefore, determining the mechanisms involved in these processes is crucial. A link between N‐methyl‐d ‐aspartate (NMDA) receptor function and social behaviors has been clearly established. The cell types in which NMDA receptors are critical for social affiliative behavior, however, remain unclear. Here, we use mice carrying a conditional allele of the NMDA R1 subunit to address this question. Mice bearing a floxed NMDAR1 (NR1) allele were crossed with transgenic calcium/calmodulin‐dependent kinase IIα (CaMKIIα)‐Cre mice or parvalbumin (PV)‐Cre mice targeting postnatal excitatory forebrain or PV‐expressing interneurons, respectively, and assessed using the three‐chambered Social Approach Test. We found that deletion of NR1 in PV‐positive interneurons had no effect on social sniffing, but deletion of NR1 in glutamatergic pyramidal cells resulted in a significant increase in social approach behavior, regardless of age or sex. Therefore, forebrain excitatory neurons expressing NR1 play an important role in regulating social affiliative behavior.     

Social Tolerance in Wild Female Crested Macaques (Macaca nigra) in Tangkoko‐Batuangus Nature Reserve,Sulawesi, Indonesia

In primates, females typically drive the evolution of the social system and present a wide diversity of social structures. To understand this diversity, it is necessary to document the consistency and/or flexibility of female social structures across and within species, contexts, and environments. Macaques (Macaca sp.) are an ideal taxon for such comparative study, showing both consistency and variation in their social relations. Their social styles, constituting robust sets of social traits, can be classified in four grades, from despotic to tolerant. However, tolerant species are still understudied, especially in the wild. To foster our understanding of tolerant societies and to assess the validity of the concept of social style, we studied female crested macaques, Macaca nigra, under entirely natural conditions. We assessed their degree of social tolerance by analyzing the frequency, intensity, and distribution of agonistic and affiliative behaviors, their dominance gradient, their bared‐teeth display, and their level of conciliatory tendency. We also analyzed previously undocumented behavioral patterns in grade 4 macaques: reaction upon approach and distribution of affiliative behavior across partners. We compared the observed patterns to data from other populations of grade 4 macaques and from species of other grades. Overall, female crested macaques expressed a tolerant social style, with low intensity, frequently bidirectional, and reconciled conflicts. Dominance asymmetry was moderate, associated with an affiliative bared‐teeth display. Females greatly tolerated one another in close proximity. The observed patterns matched the profile of other tolerant macaques and were outside the range of patterns of more despotic species. This study is the first comprehensive analysis of females’ social behavior in a tolerant macaque species under natural conditions and as such, contributes to a better understanding of macaque societies. It also highlights the relevance of the social style concept in the assessment of the degree of tolerance/despotism in social systems. Am. J. Primatol. 75:361‐375, 2013. © 2013 Wiley Periodicals, Inc.     

Aggression and social support predict long‐term cortisol levels in captive tufted capuchin monkeys (Cebus [Sapajus] apella)

Many nonhuman primates live in complex social groups in which they regularly encounter both social stressors such as aggression and social support such as that provided by long‐term affiliative relationships. Repeated exposure to social stressors may result in chronically elevated cortisol levels that can have deleterious physical effects such as impaired immune function, cardiovascular disease, and reduced brain function. In contrast, affiliative social relationships may act as a buffer, dampening the release of cortisol in response to acute and chronic stressors. Understanding how social stressors and social support predict cortisol levels is therefore essential to understanding how social situations relate to health and welfare. We studied this relationship in 16 socially housed captive brown capuchin monkeys (Cebus [Sapajus] apella) by comparing long‐term hair cortisol levels with behavioral measures of social stress (dominance rank, rank certainty, and amount of aggression received) and social support (amount of affiliation and centrality in the affiliative social network of the group). Dominance rank, rank certainty, amount of affiliation, and age were not significant predictors of long‐term cortisol levels in this population. Instead, long‐term cortisol levels were positively related to the amount of aggression received and negatively related to centrality in the affiliative social network of the group. This pattern may be attributed to the species’ socially tolerant dominance system and to the availability of social support across the dominance hierarchy.     

The Impact of Cognitive Testing on the Welfare of Group Housed Primates

Providing cognitive challenges to zoo-housed animals may provide enriching effects and subsequently enhance their welfare. Primates may benefit most from such challenges as they often face complex problems in their natural environment and can be observed to seek problem solving opportunities in captivity. However, the extent to which welfare benefits can be achieved through programmes developed primarily for cognitive research is unknown. We tested the impact of voluntary participation cognitive testing on the welfare of a socially housed group of crested macaques (Macaca nigra) at the Macaque Study Centre (Marwell Zoo). First, we compared the rate of self-directed and social behaviours on testing and non-testing days, and between conditions within testing days. Minimal differences in behaviour were found when comparing testing and non-testing days, suggesting that there was no negative impact on welfare as a result of cognitive testing. Lipsmacking behaviours were found to increase and aggressive interaction was found to decrease in the group as a result of testing. Second, social network analysis was used to assess the effect of testing on associations and interactions between individuals. The social networks showed that testing subjects increased their association with others during testing days. One interpretation of this finding could be that providing socially housed primates with an opportunity for individuals to separate from the group for short periods could help mimic natural patterns of sub-group formation and reunion in captivity. The findings suggest, therefore, that the welfare of captive primates can be improved through the use of cognitive testing in zoo environments.     

Effects of food,proximity, and kinship on social behavior in ringtailed lemurs

Efforts to understand the variation in primate social systems and their underlying interaction patterns have focused on both intrinsic and extrinsic factors. In the socioecological model, food distribution and abundance have been argued to be the primary influences on the social behavior of primate species. We examined the relationship of food resources and two intrinsic factors—kinship and proximity—with patterns of affiliative and agonistic relationships in two semi‐free ranging ringtailed lemur, Lemur catta, social groups (N=14) at The Duke Lemur Center in Durham, NC. In analyzing these three factors concurrently within the same system, we attempt to establish their relative power in explaining the characteristics of social relationships. Patterns of affiliation and high‐intensity agonism were best explained by kinship. Proximity also explained affiliation but did not explain agonism, which varied considerably between groups. The influence of food on social interactions was highly variable between the two groups and, therefore, did not convincingly account for the social behavior patterns we observed. Finally, different intensities of agonism have different patterns and should be analyzed individually. The variation between social groups makes it difficult for us to conclude that any one factor is primarily and universally responsible for patterns of social behavior in this species. Am. J. Primatol. 72:981–991, 2010. © 2010 Wiley‐Liss, Inc.     

Case Studies of the Impacts of Cataract Surgery on Crested Penguin Welfare

As nonhuman animals age, geriatric individuals require additional care and veterinary support to ensure their well being. The focus on lifelong care is a relatively newer approach when providing good welfare, and few studies have examined how veterinary care impacts behavior at different ages or how best to accommodate geriatric individuals in zoos. The objectives of this study were to (a) assess both the immediate and long-term (one year later) behavioral impacts of cataract removal for macaroni (Eudyptes chrysolophus) and southern rockhopper (Eudyptes chrysocome) penguins; (b) compare the behavior of penguins following cataract surgery to that of other conspecifics in the same habitat; and (c) monitor the impacts of cataract surgery on swimming behavior using time-depth recorders. Individual responses to cataract removal differed in direction and magnitude, and these mixed results highlight that welfare is experienced and thus measured at the individual level. Positive responses included increased habitat use, increased time spent swimming, and increased rates of affiliative interactions. This study highlights the importance of assessing welfare impacts of veterinary interventions on geriatric individuals.     

Introducing a fourth primate species to an established mixed‐species exhibit of African monkeys

Five red‐capped mangabeys (Cercocebus torquatus) were gradually introduced to an established mixed‐species exhibit containing six black and white colobus, seven mandrills, and six sooty mangabeys. Interspecific interactions were documented throughout the 3‐month introduction period and for an additional 3 months immediately thereafter. In addition, each species' behavior and exhibit use were documented before and after the addition of the fourth species. Minimal interactions were observed between the red‐capped mangabeys and the colobus or mandrills, and neither species was significantly affected by this addition. Many affiliative and aggressive interactions and changes in behavior were documented in the sooty mangabeys. However, this study shows that even closely related allopatric species can coexist in a captive environment, and the animals can benefit from this association. Zoo Biol 23:95–108, 2004. © 2004 Wiley‐Liss, Inc.     

Examining deep litter as environmental enrichment for a family group of wolf's guenons,Cercopithecus wolfi

Manipulable substrates promote species‐typical behavior and decrease abnormal behavior in a variety of primate species. However, the effects of providing litter to arboreal primates are not as well studied, and there is little information specifically concerning enrichment for guenons. To inform the captive management of an under‐studied species, we evaluated deep litter substrate as environmental enrichment for a family group of Wolf's guenons, Cercopithecus wolfi. We expected it to promote species‐typical behavior and to act as an intervention by reducing aggressive behaviors targeted toward a juvenile group member by his parents. We compared the guenons' behavior during baseline periods in which normal husbandry routines were followed to periods when the entire floor of their enclosure was covered with 30 cm of straw or wood wool. We then evaluated the group's preference between litters by comparing their relative use. The guenons spent more time feeding and were more active during both litter conditions, but relative to their respective baselines, they spent more time examining straw and less time examining wood wool. Straw, but not wood wool, promoted some affiliative behavior as well as greater tolerance of the juvenile's social proximity to others. However, the addition of deep litter did not ameliorate patterns of agonistic behavior among our subjects. Our results suggest that straw conferred greater behavioral benefits than wood wool as a deep litter substrate for this guenon group and may constitute a form of environmental enrichment for this species. Zoo Biol 29:626–632, 2010. © 2009 Wiley‐Liss, Inc.     

Post-Conflict Affiliation in Two Captive Groups of Black-and-White Guereza Colobus guereza

Post‐conflict affiliation was studied in two captive groups of black‐and‐white guereza (Colobus guereza), a folivorous, arboreal species which lives in harems. The overall level of aggression was low and each individual was involved in only 0.054 aggressive interactions per hour. After 132 aggressive interactions observed during 364 h, former antagonists were found to seek each other out selectively and exchange affiliative behaviours. The first affiliative behaviour was likely to occur within the first minute after the end of the conflict. The post‐conflict affiliative behaviours most often seen were proximity, social grooming, embrace, reciprocal low‐intensity mouth‐opening, groom present and gentle hand touch, in descending order. The pattern of post‐conflict affiliation is thus similar to that observed in most other primate species studied. One notable exception seems to be the relatively high proportion of conflicts after which former opponents continue to remain within arm's reach (in 1/3 of the conflicts). If these instances of remaining‐in‐proximity were excluded, the corrected conciliatory tendency according to Veenema et al. (1994, Behav. Proc. 31, 29–38) was 45% (60% if they were included).     

Changes in Social Behavior and Their Hormonal Correlates during Pregnancy in Pig-tailed Macaques

I conducted a longitudinal study of hormones and social behavior during pregnancy in 8 female pig-tailed macaques (Macaca nemestrina) living in a captive social group. Females exhibited reduced grooming activity after the first month of pregnancy and reduced aggressiveness in the last month. Female-male hindquarter presentations and male-female foot-clasp mounts decreased steadily during pregnancy. The week before parturition was associated with lower involvement in all social activities. Monthly changes in plasma concentrations of estradiol and progesterone are correlated with some changes in sexual behavior and grooming performed by pregnant females. Altogether, the findings suggest that pregnancy does not bring about a major disruption of female social relationships with other group members and that the influence of pregnancy hormones on female affiliative and agonistic behavior is less marked than that previously observed for infant-directed behavior.     

Comparison of two introduction methods for African elephants (Loxodonta africana)

Managers must consider an animal's potential for aggression when they decide to change or form a captive social group formation. In this study we compared two introduction methods (termed “sequential” and “nonsequential” introductions) in African elephants to assess their effectiveness in managing aggression and minimizing stress. Both introduction methods included four phases: baseline, visual contact, limited tactile contact, and physical introduction. In the sequential introduction, these steps were followed sequentially, and empirical data were considered during decision‐making. In the nonsequential introduction, these steps were not followed sequentially, and decision‐making was based primarily on intuitive assessments by animal managers. Behavioral data and fecal corticoid concentrations were measured throughout both types of introduction. The behavior categories measured included active aggression, passive aggression, submissive behavior, undesirable/stress‐related behavior, and affiliative behavior. While the role of affiliative behavior was surprising, general behavior patterns were characterized by increases in behavior as animals progressed to the next phase of introduction regardless of introduction type. These increases then attenuated over time during each phase. Overall, less behavior was observed during the sequential introduction, as predicted. The data suggest that the sequential introduction managed aggression more effectively. Similar patterns were predicted for undesirable/stress‐related behavior and fecal corticoid concentration. Undesirable/stress‐related behavior was a poor predictor of observed behavior patterns. Although the patterns differed from those predicted, higher concentrations of fecal corticoids were measured during the nonsequential introduction and correlated significantly only with submissive behavior. While more investigation is warranted, the data indicate that the nonsequential introduction brought about an increased physiological response. Overall, the sequential introduction method appeared to manage aggression and stress better than the nonsequential technique. Every introduction is subject to factors that can influence success, such as staff experience, the design of the facility, and the animals' social histories. It is hoped that the rigorous sequential protocol will be a useful tool in the animal manager's “toolbox” for planning and implementing introductions. Applications of this introduction method are also discussed. Zoo Biol 23:109–126, 2004. © 2004 Wiley‐Liss, Inc.     

Evaluating changes in salivary oxytocin and cortisol following positive reinforcement training in two adult male western lowland gorillas (Gorilla gorilla gorilla)

Positive reinforcement training (PRT) is associated with increases in species-typical behavior and decreases in stereotypic and abnormal behavior in participating animals. Physiological changes following PRT, for example, increases in oxytocin (OXT) and/or decreases in cortisol (CORT), may facilitate these behavioral changes. This study evaluated salivary OXT and salivary CORT concentrations in two adult male western lowland gorillas (Gorilla gorilla gorilla) following PRT with their primary animal care staff. Following PRT, no change in OXT was observed. CORT decreased in one subject following PRT. Changes in endogenous OXT are related to affiliative interactions and interact with strongly bonded conspecifics. PRT may not activate the oxytocinergic system because PRT is not a species-specific affiliative interaction and/or animal care staff are not viewed as conspecifics. Regardless, PRT may still be viewed as a positive interaction resulting in stress reduction via a decrease in CORT. Relationships are unique, thus these results only apply to these two gorillas and one animal caregiver. Larger population-level studies are needed to understand overall trends in human–animal interactions, and ultimately human–animal relationships. Further evaluation of physiological changes following human–animal interactions should be informative for understanding the human–animal relationship in zoos.     

Treatment of Morbid Obesity in Low‐income Adolescents: Effects of Parental Self‐monitoring

Objective: This study examined the extent to which consistency of self‐monitoring by participants and their parents was related to weight control over an initial period of 3 months within the context of a treatment program for morbidly obese low‐income minority adolescents. Research Methods and Procedures: Eighty‐three obese adolescents (mean age, 13.0 years; 51% boys; 92% African American; mean BMI, 43.0 kg/m²; mean BMI z‐score, 6.0) and at least one parent participated in a long‐term treatment program that included a very‐low‐fat dietary focus, weekly group cognitive‐behavior therapy, monthly nutrition education classes, a 12‐week physical therapy class, and medical monitoring. Results: Participants who self‐monitored on the majority of days compared with those who did not self‐monitor at all or who self‐monitored infrequently attended more sessions and generally lost more weight over the first 3 months. Although parents signed behavioral contracts committing to self‐monitor their own eating and exercising over the first month, only 12% did so. Nonetheless, participants whose parents self‐monitored were much more likely to self‐monitor consistently and lose weight during the first 3 months. Discussion: These results indicate that self‐monitoring is a cornerstone of successful weight control even for morbidly obese low‐income minority adolescents; targeting consistency of self‐monitoring among these high‐risk weight controllers and their parents should be just as important as it is for more affluent and less overweight adolescents.     

Living together: behavior and welfare in single and mixed species groups of capuchin (Cebus apella) and squirrel monkeys (Saimiri sciureus)

There are potential advantages of housing primates in mixed species exhibits for both the visiting public and the primates themselves. If the primates naturally associate in the wild, it may be more educational and enjoyable for the public to view. Increases in social complexity and stimulation may be enriching for the primates. However, mixed species exhibits might also create welfare problems such as stress from interspecific aggression. We present data on the behavior of single and mixed species groups of capuchin monkeys (Cebus apella) and squirrel monkeys (Saimiri sciureus) housed at the Living Links to Human Evolution Research Centre in the Royal Zoological Society of Scotland's Edinburgh Zoo. These species associate in the wild, gaining foraging benefits and decreased predation. But Cebus are also predators themselves with potential risks for the smaller Saimiri. To study their living together we took scan samples at ≥15 min intervals on single (n=109) and mixed species groups (n=152), and all occurrences of intraspecific aggression and interspecific interactions were recorded. We found no evidence of chronic stress and Saimiri actively chose to associate with Cebus. On 79% of scans, the two species simultaneously occupied the same part of their enclosure. No vertical displacement was observed. Interspecific interactions were common (>2.5/hr), and equally divided among mildly aggressive, neutral, and affiliative interactions such as play. Only one aggressive interaction involved physical contact and was non‐injurious. Aggressive interactions were mostly (65%) displacements and vocal exchanges, initiated almost equally by Cebus and Saimiri. Modifications to the enclosure were successful in reducing these mildly aggressive interactions with affiliative interactions increasing in frequency and diversity. Our data suggest that in carefully designed, large enclosures, naturally associating monkeys are able to live harmoniously and are enriched by each other. Am. J. Primatol. 72:33–47, 2010. © 2009 Wiley‐Liss, Inc.