Chimpanzees (Pan troglodytes) in U.S. Zoos, Sanctuaries, and Research Facilities: A Survey-Based Comparison of Species-Typical Behaviors

A survey was sent to zoos, research facilities, and sanctuaries which housed chimpanzees. Data collected included information about 1122 chimpanzees’ age, sex, social group-size, rearing history, and enclosure. Respondents were also asked to indicate if certain behaviors had been observed in each chimpanzee over the prior two years. Species- typical behaviors (STBs) were queried, including copulation, tool-use, nest-building, and social grooming. Tool-use was reported present for 94.3% of the sample (n = 982), active social grooming for 85.7% (n = 1121), copulation for 68.3% (n = 863) and nest-building for 58.9% (n = 982). Of the subjects for whom we had data regarding all four STBs (n = 860), 45.6% were reported to engage in all four. Logistic regression analyses using forward Wald criteria were conducted to determine the best model for each STB based on the predictors of age, sex, rearing history, group-size, facility-type, and a sex-by-rearing interaction. The best model for copulation (χ2(6) = 124.62, p < 0.001) included rearing, group-size, facility-type, and the sex-by-rearing interaction. Chimpanzees were more likely to copulate if they were mother-reared, in larger groups, living in research facilities, and, if not mother-reared (NOTMR), more likely to copulate if they were female. The best model for tool-use retained the predictors of age category, facility-type, and sex-by-rearing (χ2(5) = 55.78, p < 0.001). Chimpanzees were more likely to use tools if they were adult, living in research facilities, and if NOTMR, were female. The best model for nest-building included facility-type and rearing (χ2(3) = 205.71, p < 0.001). Chimpanzees were more likely to build nests if they were MR and if they were living in zoos or in sanctuaries. The best model for active social grooming retained the predictors of age, sex, rearing, and type of facility (χ2(6) = 102.15, p < 0.001). Chimpanzees were more likely to engage in active social grooming if they were immature, female, mother-reared, and living in zoos. This research provides a basic behavioral profile for many chimpanzees living under human care in the United States and allows us to determine potential methods for improving the welfare of these and future chimpanzees in this population.

Predictors of Long-Term Social Compatibility in Rhesus Macaques (Macaca mulatta) Housed in Research Settings

Social housing improves the well-being of monkeys in research settings; however, little is known about factors influencing the long-term stability of established, full-contact pairs. Archival data were examined to determine whether sex, age, weight, duration pair housed, familiarity, social interruptions, room changes, or sedation events predicted eventual separation of pairs for social incompatibility (n = 80) or for nonsocial reasons (e.g., research or health needs) (n = 1143). Using a logistic regression model (Wald Χ2(8) = 42.325, p < .001), three significant factors were identified. Pairs in which partners had known prior familiarity in group housing were less likely to experience social incompatibility (p = .034). Pairs housed together longer (p < .001) and who staff had temporarily separated through the placement of a cage divider to reduce physical contact were more likely to require permanent separation for social incompatibility (p < .001); additional analysis revealed that dividers were often placed for social reasons, suggesting early signs of social instability. Findings may be useful for primate caregivers when making decisions about managing social partners.

Improving transparency-A call to include social housing information in biomedical research articles involving nonhuman primates

The social setting of animal subjects in the research environment has known effects on a variety of dependent measures used in biomedical research. Proper evaluation of the robustness of published research is dependent upon transparent, detailed, and accurate reporting of research methods, including the animals' social housing conditions. However, to date, most research articles utilizing nonhuman primates (NHPs) provide only partial data on this topic, hampering transparency, and reproducibility. Therefore, we call for the inclusion of information pertaining to the social aspects of the animals' housing conditions in publications involving NHPs to improve transparency. We argue that including this information in scientific publications is crucial for the interpretation of research findings in the appropriate context and for understanding unexplained variability in study findings. Finally, the inclusion of this information in publications will additionally familiarize scientists with how other researchers conducting similar studies are housing their animals and will encourage them to consider the implications of various housing conditions on their research outcomes.

Weight management towards physiological and behavioral wellbeing for chimpanzees living under human care

Across a period of 54 months, several changes were made to the feeding protocols of 32 adult chimpanzees living at the Yerkes National Primate Research Center Field Station. Before implementing any changes in diet, baseline data were collected for 6 months. During Baseline (BS), the chimpanzees received unlimited amounts of primate biscuits twice a day and a limited amount of produce as enrichment. Treatment One (T1) dietary modifications included an increased amount of vegetables, primarily leafy greens, and biscuit feedings scheduled to occur an hour after vegetables were provided to the chimpanzees. T1 lasted for 1 year. At the end of T1, most of the chimpanzees had gained weight. Treatment Two (T2) occurred over the span of 3 years, during which all the chimpanzees were switched from unlimited, group-distributed primate biscuits to individually prescribed amounts of biscuits, fed in\dividually, and increased daily feedings of leafy greens. By the end of T2, 10 of 15 chimpanzees who were overweight or obese at the start of the project were within range of ideal body condition, and 4 of the remaining 5 were improved. All the chimpanzees who started the project within ideal range were still within ideal range. Significantly more time was invested in eating, foraging, and processing food during T2 (p < .05), more appropriately replicating the natural time budget for a chimpanzee. There were not any increases in abnormal, stress-related, or agonistic behaviors as a function of dietary modifications. Inactivity, however, was significantly higher (p < .05) during the later protocol, and locomotion was concurrently lower (p < .05).

Contribution of adult sex ratio to trauma and reproductive output in large breeding groups of rhesus macaques (Macaca mulatta)

Maintaining stable breeding groups of rhesus macaques (Macaca mulatta) can be challenging due to the complex social dynamics and despotic nature of the species. Trauma from aggression is a common problem in rhesus colonies and can cause social disruption, strain veterinary and animal management resources, and potentially affect reproduction. Previous research has shown that increasing the number of non-natal adult males in a breeding group can improve group stability, reduce trauma, and increase reproduction. Here, we used mixed-effects regression models to examine the effects of sex ratio and other factors on trauma and reproduction at the Yerkes National Primate Research Center using a historical dataset made up of four large rhesus groups over an eleven-year period (2003–2013). As expected, sex ratio was a significant predictor for both trauma and reproduction. However, group age since formation was a stronger predictor of trauma frequency and the amount of space available was a slightly better predictor of reproduction than sex ratio or trauma. These results indicate that improving sex ratios can be a viable management strategy to reduce trauma and improve reproduction, particularly when it is difficult to manipulate the group compositions and/or their housing situations. Reducing trauma is a primary goal for rhesus breeding colonies, as it directly impacts the monkeys' health and psychological well-being. Such improvements are necessary for the ethical treatment and care of the animals themselves, but also to reduce financial burdens and maintain a healthy colony for research purposes.

Female social structure influences, and is influenced by, male introduction and integration success among captive rhesus macaques (Macaca mulatta)

Animal social structure is influenced by multiple socioecological factors. Of these, the links between changes to group demography through the arrival of new individuals and residents' social structure remain unclear. Across seven groups of captive rhesus macaques (Macaca mulatta), we examine how male introductions may be influenced by, and in-turn influence, aspects of female social structure. GLMMs revealed that males integrated more successfully into groups in which females showed more 'despotic' social structures, i.e., higher aggression rates, steeper dominance hierarchies, and greater rank-skew in allogrooming network connectedness. Yet during periods that followed males' social integration, females increased their social tolerance (decreased aggression and shallower hierarchies) and group cohesivity (less clustered allogrooming networks), but retained their tendencies to groom dominants. Our findings, independent of group size and matrilineal relatedness, help better understand how dispersal/immigration may influence social structure, and how assessing changes to social structure may inform macaque welfare and management.

Factors influencing the success of male introductions into groups of female rhesus macaques: Introduction technique, male characteristics and female behavior

In captive populations of rhesus macaques, novel adult males are commonly introduced to female groups every few years to prevent inbreeding, which mimics male dispersal in wild macaque populations. However, introducing adult males is challenging because macaques are aggressive to newcomers, which can result in serious injuries. Efforts to reduce trauma risk during the introduction process and increase the probability of success are needed. Here we investigate the impact of multiple factors, including male attributes (e.g., age, weight, rank, and experience), introduction method (punctuated vs. continual exposure to females), and female behavior, on males' trauma risk and integration success. We studied eight introductions of multimale cohorts (3-7 males each; N = 36 total) into existing female groups of rhesus macaques at the Yerkes National Primate Research Center. Four cohorts were introduced using the punctuated exposure method where adult males were moved each morning from run housing to the females' indoor enclosure and returned to run housing in the afternoon, and four cohorts were introduced using the continual exposure method where adult males were moved to an introduction enclosure attached to the females' outdoor compound, allowing males to live in protected contact next to the female group continuously. Generalized linear mixed models fitted to trauma risk (e.g., latency to first trauma; total trauma count) and success or failure to integrate (i.e., continual residence within the female group for greater than 53% of days within a 28-day window after first overnight stay) showed that continual exposure to females in the introduction enclosure reduced male trauma risk and increased the likelihood of successful integration compared to punctuated exposure. Males received less trauma when they received a higher rate of grooming from females. Male attributes had no effect. These findings highlight the importance of introduction technique and female behavior in the process of males' social integration into female groups.

Effects of medroxyprogesterone acetate on social behavior in female rhesus macaques (Macaca mulatta) depend on male breeding season introductions

BACKGROUND

Although medroxyprogesterone acetate (MPA) is used commonly as a contraceptive in women and female non-human primates, its effects on social behavior remain unclear. This study examined whether MPA treatment and introduction of new adult males during the breeding season influence the social behaviors of group-housed adult female rhesus macaques.

METHODS

Subjects were 12 MPA-treated and 12 matched case-control females. Aggressive, affiliative, and sexual behaviors were measured.

RESULTS

MPA-treated females showed less affiliative and sexual behavior compared to matched controls during the breeding season. MPA treatment was associated with decreased aggression emitted toward and received from females during the breeding season.

CONCLUSION

MPA treatment is associated with differences in social behavior of female rhesus macaques during the breeding season, when normal hormonal cycles are attenuated by the treatment, but there is no indication that MPA-treated females bring an additional risk for more aggression during the male introduction and breeding season.

Use of Introduction Enclosures to Integrate Multimale Cohorts into Groups of Female Rhesus Macaques (Macaca mulatta)

Integrating animals into a new group is a challenge for both free-ranging and captive adult male rhesus monkeys (Macaca mulatta), and for females in groups receiving new males. To ensure the genetic viability of the population, however, male transfers must occur in both natural and captive settings. To facilitate the introduction of groups of adult males to adult females, we designed a new enclosure that is attached to the outdoor compound where females are housed. Here we describe the construction of 3 introduction enclosures, their use during 4 introductions of groups of adult males to adult females, a brief comparison of introduction success rates associated with the new introduction enclosures with those of our traditional male introduction method, and a critique by the various groups of staff members working with the new enclosures. Overall, the introduction enclosures benefitted both the macaques and the facility personnel and appear to be a useful enhancement to our process of integrating breeding groups.

Survey of Behavioral Indices of Welfare in Research Chimpanzees (Pan troglodytes) in the United States

Chimpanzees demand specialized housing and care and the highest degree of attention to animal welfare. The current project used a survey method to collate information on chimpanzee housing and behavioral indices of welfare across all 6 of the chimpanzee research facilities in the United States. Data were compiled on 701 chimpanzees ranging from 2 to 62 y old (mean age, 26.0 y). All chimpanzees except for one were socially housed; the median group size was 7 animals, and group sizes ranged from 1 to 14. All of the subjects had access to outdoor spaces each day. Daily access to a natural substrate in the chimpanzee's enclosure was available for 63.8% of the subjects. Overall, 94.1% of the chimpanzees used tools to acquire food, 48.1% built nests, 75.8% copulated, and 83.3% initiated grooming bouts. The following atypical behaviors were reported most often: rocking (13.0%), coprophagy (10.0%), and stereotyped behaviors other than rocking (9.4%). There was widespread evi- dence of positive animal training techniques, with nearly all (97.7%) subjects reported to generally voluntarily cooperate with shifting in their enclosure, and 72.2% were reported to present for an injection of anesthetic. We include some comparison between these findings and data describing zoo-housed chimpanzees. In addition, we discuss survey findings in reference to recommendations made by the NIH Working Group on the Use of Chimpanzees in NIH-supported Research. The current survey assessed a larger sample of chimpanzees living under human care than has been published previously. This broad analysis can help to guide future improvements in behavioral management to address behavioral problems or deficits.

Systematic assessment of food item preference and reinforcer effectiveness: Enhancements in training laboratory-housed rhesus macaques

The use of systematic preference assessments can enhance positive reinforcement training with captive animals. We found that the multiple stimulus without replacement (MSWO) technique identified food preferences in laboratory housed rhesus macaques, with raisins and grapes being ranked higher on average than dried apricot, pasta, and green beans (Friedman Test, χ2 (4) = 35.52, p < .001). Agreement between individuals (N = 21) was moderate (Kendall's W = 0.42), and consistency across time varied among individuals (W = .03-.90). Highly preferred items identified by the MSWO assessment were subsequently found to increase subjects' engagement in a husbandry task on which they were being trained (Mann-Whitney U = 6.00, p = .002) and to improve performance on a progressive ratio schedule (Wilcoxon signed-rank test, Z = -2.17, p = .03) when compared with low preference items. The progressive ratio technique supplements other preference assessment techniques by measuring the amount of work a subject will do to gain access to an item. The use of more effective reinforcers identified through systematic assessment has the potential to increase animal performance on husbandry and research tasks and to improve animal welfare in the laboratory setting.

Two Methods of Social Separation for Paired Adolescent Male Rhesus Macaques (Macaca mulatta)

Literature-based recommendations regarding how to separate pairs of laboratory-housed NHP when required for research, veterinary, or management needs are unavailable. This study assessed 2 separation techniques-rapid and stepwise-to determine whether a period of limited social access mitigates the behavioral stress response after complete separation. Researchers observed 12 pairs of mother-reared, adolescent male rhesus macaques before and after separation with a solid divider; 6 of the pairs experienced a transitional week of limited social access through a perforated panel. Observers collected 30-min focal animal scans during study phase, totaling 144 h of behavioral data. Target behaviors included those classified as protest, agitation, tension, and withdrawn or self-directed. Social separation resulted in a significant change in behavior. Separated monkeys displayed more withdrawn or self-directed behaviors (for example, huddling, self-directed stereotypies) than when pair-housed. Stepwise separation resulted in increased agitation behaviors in the limited contact phase and did not mitigate separation effects. Adverse behavioral changes during the limited contact phase support continuous pair housing until required individual housing.

An International Survey of Approaches to Chair Restraint of Nonhuman Primates

Specifically designed restraint chairs are the preferred method of restraint for research studies that require NHP to sit in place for sustained periods of time. In light of increasing emphasis on refinement of restraint to improve animal wellbeing, it is important to have a better understanding of this potentially stressful procedure. Although chair restraint is used internationally, very little published information is available on this subject. We developed a survey to obtain an overview of equipment, procedures, and plans for improvement regarding chair restraint. We received 101 responses from people working in academic, government, contract research, and pharmaceutical laboratories within the Americas, Europe and Asia. Findings indicate that the majority of laboratories using restraint chairs work with macaque species. Restraint chairs are used for a wide range of procedures, including cognitive testing, recording neuronal activity, functional MRI, intravenous infusion, and blood sampling. Approximately 2/3 of laboratories use an enclosed 'box chair,' which the animal is trained to enter and then to extend its head through an opening on the top of the chair; the remaining one third of laboratories use an 'open chair' design, in which manual handling or the pole-and-collar system is used to transfer and secure the animal into the chair. Respondents reported that when selecting the type of chair to use, they considered comfort for the animal, ease of use, and the ability to adjust fit between animals of different sizes. Various training methods and timeframes are used to prepare macaques for restraint chair procedures. Several laboratories are incorporating greater use of positive reinforcement training. The community that uses these restraint procedures needs to work together to define best practice; our survey results can help in that effort.

Pair housing of Macaques: A review of partner selection, introduction techniques, monitoring for compatibility, and methods for long-term maintenance of pairs

Pair housing of macaques has become a widely implemented compromise between meeting the social needs of the monkeys and allowing for their use in biomedical research. While beneficial to the animals, pair housing can provide challenges for those caring for them. Drawing from both scientific literature and direct experience, this paper provides a review of practical aspects of pair housing including partner selection, pairing methodologies, staff education, and equipment considerations. Recommendations include selecting a pairing method appropriate to the facility and the individual animals being paired, educating staff on social behavior, and establishing a pair monitoring program to facilitate long-term pair maintenance. Assessment of behavior is essential in determining the compatibility of new pairs and in identifying established pairs that may need interventions to enhance their long-term compatibility. The pair housing program at the Yerkes National Primate Research Center is described as one model of a successful program. Am. J. Primatol. 79:e22485, 2017. © 2015 Wiley Periodicals, Inc.

Position Statement: "Functionally Appropriate Nonhuman Primate Environments" as an Alternative to the Term "Ethologically Appropriate Environments"

The American Society of Primatologists (ASP), the Association of Primate Veterinarians (APV), and the American College of Laboratory Animal Medicine (ACLAM) have come together to develop this position statement in which the term "functionally appropriate nonhuman primate environments" is proposed as a better descriptor and as an alternative to the previously used term, "ethologically appropriate environments" to describe environments that are suitable for nonhuman primates involved in biomedical research. In 2015, the United States Department of Agriculture requested comments on a petition which called for amending the Animal Welfare Act so that all research primates would be housed in "ethologically appropriate physical and social environments." We are critical of this term because: (1) it does not provide clarification beyond that in current regulatory language; (2) it does not provide for balance between animal welfare goals and the reasons why the primates are housed in captivity; (3) it discounts the adaptability that is inherent in the behavior of primates; (4) it conveys that duplication of features of the natural environment are required for suitable holding environments; (5) objective studies reveal that environments that appear to be more ethologically appropriate do not necessarily better meet the needs of animals; and (6) using the term "ethology" is inherently confusing. We propose that the term "functionally appropriate nonhuman primate environments" be used instead, as it emphasizes how environments work for nonhuman primates, it better describes current activities underway to improve nonhuman primate welfare, and the balance that is achieved between meeting the needs of the animals and the requirements of the research in which they are involved.

Behavioral Effects of an Enhanced Enrichment Program for Group-Housed Sooty Mangabeys (Cercocebus atys)

Evaluating the behavioral effects of enrichment on animals housed in biomedical facilities is necessary to effectively support their care and wellbeing. We tested the cumulative effects of an enhanced enrichment program on sooty mangabey behavior: locomotion, feeding and foraging, manipulating items in the enclosure, social affiliation, aggression, and abnormal behavior. The enhanced enrichment program included the addition of a substrate (timothy hay), widely distributing small pieces of produce and a forage mixture in the hay, adding structures and perching, and increasing the variety of food items, foraging devices, and other manipulable items. We tested 10 groups living in runs (n = 54) by using an ABA experimental design (phase A, standard enrichment; phase B, enhanced enrichment) and Wilcoxon signed-rank tests to compare behavior across phases. During phase B, subjects significantly increased feeding, foraging, and manipulation of items, and they decreased self-grooming, social affiliation, and aggression. Combined enrichment use increased from approximately 10% to 21% of the mangabeys' time. Enhanced enrichment did not affect locomotion or abnormal behavior. The increases in feeding, foraging, and manipulation during enhanced enrichment were driven primarily by the subjects' preference for foraging in the hay: it was the most effective component of the program in promoting feeding and foraging behavior, which comprises the majority of wild sooty mangabeys' daily activity. Developing an effective, species-appropriate, and comprehensive enrichment program is essential to successfully promote the health and wellbeing of captive NHP.

Characterizing abnormal behavior in a large population of zoo-housed chimpanzees: prevalence and potential influencing factors

Abnormal behaviors in captive animals are generally defined as behaviors that are atypical for the species and are often considered to be indicators of poor welfare. Although some abnormal behaviors have been empirically linked to conditions related to elevated stress and compromised welfare in primates, others have little or no evidence on which to base such a relationship. The objective of this study was to investigate a recent claim that abnormal behavior is endemic in the captive population by surveying a broad sample of chimpanzees (Pan troglodytes), while also considering factors associated with the origins of these behaviors. We surveyed animal care staff from 26 accredited zoos to assess the prevalence of abnormal behavior in a large sample of chimpanzees in the United States for which we had information on origin and rearing history. Our results demonstrated that 64% of this sample was reported to engage in some form of abnormal behavior in the past two years and 48% of chimpanzees engaged in abnormal behavior other than coprophagy. Logistic regression models were used to analyze the historical variables that best predicted the occurrence of all abnormal behavior, any abnormal behavior that was not coprophagy, and coprophagy. Rearing had opposing effects on the occurrence of coprophagy and the other abnormal behaviors such that mother-reared individuals were more likely to perform coprophagy, whereas non-mother-reared individuals were more likely to perform other abnormal behaviors. These results support the assertion that coprophagy may be classified separately when assessing abnormal behavior and the welfare of captive chimpanzees. This robust evaluation of the prevalence of abnormal behavior in our sample from the U.S. zoo population also demonstrates the importance of considering the contribution of historical variables to present behavior, in order to better understand the causes of these behaviors and any potential relationship to psychological wellbeing.

Effects of changing housing conditions on mangabey behavior (Cercocebus atys): Spatial density, housing quality, and novelty effects

The separate influences of spatial density and housing quality on the behavior of captive animals are difficult to measure because the two factors are often intrinsically linked. Here, we recorded affiliative and agonistic behavior in adult sooty mangabeys in various housing situations, testing spatial density and housing quality changes separately (N = 26 experienced spatial density changes; N = 12 experienced housing quality changes). We varied spatial density by 50% while holding housing quality constant and we varied housing quality while holding spatial density constant (achieved by comparing two types of run-housing that varied in the amount of visual privacy and outdoor access). Each housing condition was one month in duration. Prior to collecting data in each housing condition, we evaluated the subjects' initial responses to the change in housing environment during 2-week novelty periods. Affiliative behavior did not change during the novelty periods. Agonistic behavior initially increased slightly when spatial density increased and it decreased significantly when spatial density decreased; it also decreased when subjects moved to housing that offered more visual privacy and outdoor space, indicating that the mangabeys were sensitive to these housing changes. After the novelty periods, affiliative behavior increased under higher spatial density, but remained unchanged across housing quality conditions; agonistic behavior remained unchanged across all conditions. Results suggest that a prolonged increase in spatial density led the mangabeys to adopt a tension-reduction coping strategy, in which the increase in affiliative behavior alleviates a presumed increase in social tension. Reducing visual privacy and choice did not affect the mangabeys' behavior, post-novelty period. Thus, like many other primates, the mangabeys managed tension by flexibly adapting to changes in their housing environment in ways that reduce the risk of severe aggression. This study highlights the importance of controlled behavioral studies in facilitating data-driven management decisions that promote animal welfare. Am. J. Primatol. 77:1001-1014, 2015. © 2015 Wiley Periodicals, Inc.

Self-Injurious Behavior Secondary to Cytomegalovirus-Induced Neuropathy in an SIV-Infected Rhesus Macaque (Macaca mulatta)

A 3.5-y-old, female rhesus macaque (Macaca mulatta) inoculated with SIVmac239 presented 8 mo later for inappetence and facial bruising. Physical examination revealed a superficial skin abrasion below the left eye, bruising below the left brow, and epistaxis of the left nostril. There were no significant findings on CBC, serum chemistry, urinalysis, or radiographs. Differential diagnoses included infectious etiologies, self-injurious behavior, immune-mediated dermatitis, and neoplasia. Lack of response to antibiotic and analgesic therapy and observations of the macaque made it apparent that the skin lesions were self-inflicted. The excoriations rapidly progressed to extend over the nose, and the left palpebrae became edematous. Euthanasia was elected because the macaque appeared to be experiencing continued discomfort despite analgesic therapy. Histopathologic examination revealed systemic cytomegalovirus (CMV) infection involving the facial nerves, periocular nerves, meninges, and perimesenteric lymph nodes. CMV is a common infection in macaques, with adult seroprevalence close to 100% in most colonies. Infection in immunocompetent animals is usually asymptomatic but can cause significant clinical disease in immunodeficient hosts. CMV is associated with a painful peripheral neuropathy in human AIDS patients, and analgesic treatment is often unsatisfactory. Peripheral neuropathy secondary to CMV should be considered as an underlying cause of self-injurious behavior in SIV-infected macaques. Macaques affected by other diseases and disorders may also be at risk for development of painful peripheral neuropathies.

Long-term effects of infant attachment organization on adult behavior and health in nursery-reared, captive chimpanzees (Pan troglodytes)

This research traces the long-term effects on health, well-being, personality, and behavior of adult chimpanzees as a function of their attachment to a primary human caregiver assessed when they were 1 year of age. Of the 46 chimpanzees assessed at 1 year of age, we assessed health in 43 individuals, adult behavior in 20 individuals, and adult well-being and personality in 21 individuals. Attachment disorganization was found to be a significant predictor of stereotypic rocking in adult chimpanzees, F(1, 18) = 7.50, p = .013. For those subjects (N = 24) with a full 20 years (birth through age 20 years) of health data available, both rearing experience and disorganized attachment were significant predictors of upper respiratory infection frequency, F(2, 21) = 8.86, p = .002. Chimpanzees with disorganized attachment exhibited average subjective well-being as adults, whereas chimpanzees with organized strategies exhibited higher than average subjective well-being as adults. These results support the findings of human attachment research and are in line with attachment-based predictions for chimpanzees, such that the consequences of an early history of disorganized attachment may be adverse and long lasting.

Refining the pole-and-collar method of restraint: emphasizing the use of positive training techniques with rhesus macaques (Macaca mulatta)

The pole-and-collar method is one of several techniques that enable the safe transfer of a nonhuman primate from its home environment into a restraint chair without the need for sedation. It has been used within the scientific community for decades. Traditional methods to train animals for pole-and-collar use rely primarily on aspects of negative reinforcement, with very little incorporation of positive-reinforcement techniques. With increasing emphasis on animal training and welfare, research facilities are incorporating positive-reinforcement training into husbandry and experimental procedures. Here we demonstrate the feasibility of training rhesus macaques (Macaca mulatta; n = 8) to cooperate for pole-and-collar transfer to a primate restraint chair. By using predominantly positive-reinforcement techniques, with supplemental elements of negative reinforcement, macaques were trained in a mean of 85 training sessions (a mean of 1085 min of training time). We also provide tools for investigators using the pole-and-collar method to help them successfully incorporate positive-reinforcement training into their procedures. This refinement has the potential to improve animal welfare and enhance the value of nonhuman primate models in research.

Play caging benefits the behavior of singly housed laboratory rhesus macaques (Macaca mulatta)

This study addresses a recommendation in The Guide for the Care and Use of Laboratory Animals to provide singly housed nonhuman primates with intermittent access to large, enriched (play) caging. Research on the potential benefits of this type of caging is limited. The present study examines the effects of play caging on behavior, activity, and enrichment use. Singly housed, adult male, rhesus macaques (n = 10) underwent a baseline phase in their home cages, a 2-wk treatment phase with housing in play cages, and a posttreatment phase after returning to their home cages. Each subject underwent focal behavioral observations (n = 10; duration 30 min each) during each study phase, for a total of 150 h of data collection. Results showed increases in locomotion and enrichment use and a trend toward decreased abnormal behavior while subjects were in the play cage, with the durations of these behaviors returning to baseline levels after treatment. Anxiety-related behaviors decreased between the treatment and posttreatment phases but not between baseline and treatment, suggesting that outside factors may have influenced the decline. During the treatment phase, subjects spent more time in the upper quadrants of the play caging and preferred a mirror and forage boards as forms of enrichment. The greatest behavioral improvement occurred during the first week in the play cage. This study provides evidence to support the benefits of play caging for singly housed rhesus macaques.

Socialization of a single hand-reared tiger cub

Given the drawbacks of hand-rearing nonhuman animals in captivity, the practice is generally avoided, but it is sometimes necessary. A few scientific publications are available to guide managers toward best practices in hand-rearing, but the majority of articles focus on hand-rearing captive primates. Less is known about hand-rearing carnivores, but early socialization appears to be critical for adult social behavior. This article documents the successful hand-rearing and reintroduction of a single female Sumatran tiger cub at Zoo Atlanta. Reintroduction included a systematic procedure that used scent trials and introduction sessions through a barrier to gauge interest and determine whether or not aggression was a problem. Based on signs of interest, reduced stress-related behaviors, and a lack of aggression, animal managers decided to proceed with reintroduction. During the introductions, the animals were not aggressive and did occasionally interact, although typical mother-infant interactions were rare. The cub has since bred naturally and successfully delivered and reared two litters of cubs. These data suggest limited exposure to an adult tiger may be adequate socialization for normal reproduction even if it is provided relatively late in the cub's development.

Menopause occurs late in life in the captive chimpanzee (Pan troglodytes)

Menopause in women occurs at mid-life. Chimpanzees, in contrast, continue to display cycles of menstrual bleeding and genital swelling, suggestive of ovulation, until near their maximum life span of about 60 years. Because ovulation was not confirmed hormonally, however, the age at which chimpanzees experience menopause has remained uncertain. In the present study, we provide hormonal data from urine samples collected from 30 female chimpanzees, of which 9 were old (>30 years), including 2 above the age of 50 years. Eight old chimpanzees showed clear endocrine evidence of ovulation, as well as cycles of genital swelling that correlated closely with measured endocrine changes. Endocrine evidence thus confirms prior observations (cyclic anogenital swelling) that menopause is a late-life event in the chimpanzee. We also unexpectedly discovered an idiopathic anovulation in some young and middle-aged chimpanzees; this merits further study. Because our results on old chimpanzees validate the use of anogenital swelling as a surrogate index of ovulation, we were able to combine data on swelling and urinary hormones to provide the first estimates of age-specific rates of menopause in chimpanzees. We conclude that menopause occurs near 50 years of age in chimpanzees as it does in women. Our finding identifies a basic difference between the human and chimpanzee aging processes: female chimpanzees can remain reproductively viable for a greater proportion of their life span than women. Thus, while menopause marks the end of the chimpanzee's life span, women may thrive for decades more.

Behavioral and hormonal consequences of transporting giant pandas from China to the United States

Zoological institutions strive to ensure the welfare of nonhuman animals in captivity. Part of this effort involves reducing the level of distress experienced by an animal to the greatest extent possible. However, some necessary zoo management practices such as transportation induce stress responses. An extensive literature exists concerning the animal welfare implications of road transportation for farm and laboratory animals. There has, however, been little focus on the effects of air transportation on wild animals in captivity. Because many endangered species are transported by air for breeding purposes, it is especially important to study the effects of stress on these species. This study investigated the behavioral and hormonal consequences of transporting 4 giant pandas (2 male-female pairs) by air from China to the United States. An autoregressive test revealed that urinary cortisol measures were highest for 2 subjects, Lun Lun and Tian Tian, during the flight than during the remainder of the 30-day period posttransport (p < .01). No long-term behavioral changes or problems emerged as a result of the transport. The study found that more research is needed to develop a complete understanding of transportation stress and welfare in captive wildlife.

Benefits of pair housing are consistent across a diverse population of rhesus macaques

Introducing singly housed rhesus macaques (Macaca mulatta) into isosexual pairs is widely considered to improve welfare. The population of laboratory rhesus macaques is heterogeneous on a variety of factors and there is little literature available to directly evaluate the influence of many of these factors on the benefits of pair housing. Subjects were 46 adult female and 18 adult male rhesus macaques housed at the Tulane National Primate Research Center and the Yerkes National Primate Research Center. Behavioral data totalling 859 h and serum cortisol levels derived from 312 serum samples were analyzed for main effects of housing condition, comparing single housing to pair housing. In addition, a series of analyses were performed to test for interactions between housing condition and seven independent variables: sex, age, prior duration of single housing, presence or absence of a history of self-injurious behavior, and dominance rank, levels of affiliation and agonism in the paired setting. After the collection of 4-8 h of baseline data and three serum cortisol samples, pairs of individuals were introduced to one another and data collection was repeated, no earlier than 4 weeks after introduction. In pair housing both female and male subjects showed decrease in abnormal behavior (females: 54% reduction; P = 0.001; males: 18% reduction; P = 0.0007) and anxiety-related behavior (females: 35% reduction; P = 0.0001; males: 41% reduction; P = 0.0001), and increases in locomotion (females: 41% increase; P = 0.0001; males: 76% increase: P = 0.002). In pair housing, there were no significant sex differences in social behavior. Descriptively, paired females spent 12% of samples engaged in affiliative behavior and 0.5% engaged in agonistic behavior (back-transformed arcsin square root means). The corresponding values for males were 12% and 0.3%. No interaction effects were detected with any of the independent variables tested in this study. Cortisol values varied with sex but did not differ between housing conditions; no differences were detected when any of the above variables were included in the statistical model. Results support the general consensus among those studying the welfare of captive primates that social housing is a potent means for promoting behavioral indicators of the psychological well-being of laboratory primates. These results are of considerable practical significance and include information that refutes common perceptions about the unsuitability of males as socialization candidates, perceived negative.

Functional analysis and treatment of human-directed undesirable behavior exhibited by a captive chimpanzee

A functional analysis identified the reinforcer maintaining feces throwing and spitting exhibited by a captive adult chimpanzee (Pan troglodytes). The implementation of a function-based treatment combining extinction with differential reinforcement of an alternate behavior decreased levels of inappropriate behavior. These findings further demonstrate the utility of function-based approaches to assess and treat behavior problems exhibited by captive animals.

Factors facilitating research: a survey of zoo and aquarium professionals

The purpose of this survey was to assess the background, training, and perceptions of professionals conducting and coordinating research at North American zoos and aquariums accredited by the Association of Zoos and Aquariums (AZA) and to identify the factors they considered critical to successful scientific programs. We analyzed responses to a 57-item questionnaire from 231 professionals at AZA zoos and aquariums. The majority of those surveyed conducted behavioral research, conducted research only in a captive setting, held curatorial positions, had their salaries supported by their institutions' operating budget, and considered themselves part of a successful scientific program. About 30% of those we surveyed possessed a doctoral research degree in comparison to 55% possessing lesser level degrees-19% with master's, 34% with bachelor's, and 2% with other degrees. Support from the chief executive officer and personnel dedicated to conducting scientific programs were judged as the two most important factors contributing to the successful scientific programs. The information provided in this report may be used to develop and improve both established and newly initiated scientific programs in zoos and aquariums.

The use of technology to enhance zoological parks

Technology can be used in a zoological setting to improve visitor experience, increase research opportunities, and enhance animal welfare. Evaluating the quality of these technological innovations and their use by nonhuman and human counterparts is a critical part of extending the uses of technology to enhance animal welfare and visitor experience at zoological parks. Survey data from a small sample of institutions housing primates suggest that computers, television, radio, and sprinklers are the most prevalent types of technological enrichment currently used. Survey respondents were positive about the technology implemented, stating a desire to increase its use.

Positive reinforcement training as enrichment for singly housed rhesus macaques (Macaca mulatta)

Positive reinforcement training is one component of behavioural management employed to improve psychological well-being. There has been regulatory promotion to compensate for restricted social housing in part by providing human interaction to singly caged primates, implying an efficacy standard for evaluating human interaction. The effect of positive reinforcement training on the behaviour of 61 singly housed laboratory rhesus macaques (Macaca mulatta) was evaluated at two large primate facilities. Training involved body part presentation and basic control behaviours. Baseline data were compared to two treatment phases presented in varying order across individuals, six minutes per week of positive reinforcement training and six minutes per week of unstructured human interaction. While a MANOVA involving behavioural categories and study conditions across study subjects was significant, univariate ANOVAs found no effect of phase within any behavioural category. Categorising subjects according to rearing, housing facility, or baseline levels of abnormal behaviour did not reveal changes in behaviour with positive reinforcement training or human interaction. This study failed to detect, to any degree, the types of behavioural changes documented in the scientific literature to result from pairing singly housed monkeys. Implementing short durations of positive reinforcement training across large numbers of singly housed animals may not be the most effective manner for incorporating positive reinforcement training in the behavioural management of laboratory macaques. Rather, directing efforts toward individuals with specific behavioural, management, clinical, research or therapeutic needs may represent a more fruitful approach to improving psychological well-being with this technique.

Positive Reinforcement Training As a Technique to Alter Nonhuman Primate Behavior: Quantitative Assessments of Effectiveness

Many suggest that operant conditioning techniques can be applied successfully to improve the behavioral management of nonhuman primates in research settings. However, relatively little empirical data exist to support this claim. This article is a review of several studies that discussed applied positive reinforcement training techniques (PRT) on breeding/research colonies of rhesus macaques (Macaca mulatta) and chimpanzees (Pan troglodytes) at The University of Texas M. D. Anderson Cancer Center and measured their effectiveness. Empirical analyses quantified the amount of time required to train rhesus monkeys to come up, station, target, and stay. Additionally, a study found that time spent affiliating by female rhesus was changed as a function of training low affiliators to affiliate more and high affiliators to affiliate less. Another study successfully trained chimpanzees to feed without fighting and to come inside on command. PRT is an important behavioral management tool that can improve the care and welfare of primates in captivity. Published empirical findings are essential for managers to assess objectively the utility of positive reinforcement training techniques in enhancing captive management and research procedures.

The influence of captive adolescent male chimpanzees on wounding: management and welfare implications

Adolescence, the period lasting from the onset of puberty to the emergence of physical and sexual maturity, is a period of social change for many species including chimpanzees. Several reports have implicitly linked the physiological changes that occur during male chimpanzee adolescence to significant disruption in the social group, which in turn may result in serious agonism and wounding. To assess the association between adolescent males and wounding rates, 38 institutions housing 399 chimpanzees among 59 social groups, recorded all wounds incurred by chimpanzees over a 6-month period. The rate of wounding did not differ between groups with or without adolescent males. Adolescent males received the most wounds, but were no more likely to cause wounds than group members of any other sex-age class. Social groups with multiple adult males experienced lower wounding rates than those with a single adult male. Results indicate that (1) adolescent male chimpanzees may receive, but not inflict, more wounds than chimpanzees in other sex-age classes; and (2) management strategies that support natural social groupings may control and limit group agonism.

Positive reinforcement training to enhance the voluntary movement of group-housed sooty mangabeys (Cercocebus atys atys)

Positive reinforcement training (PRT) has successfully been used to train diverse species to execute behaviors helpful in the everyday care and wellbeing of the animals. Because little information is available about training sooty mangabeys (Cercocebus atys atys), we analyzed PRT with a group of 30 adult males as they were trained to shift from 1 side of their enclosure to the other. Over a 4-mo period we conducted 57 training sessions totaling 26.5 h of training and recorded compliance information. During training, compliance increased from 76% of the animals during the first 5 training sessions to 86% of the animals shifting during the last 5 sessions. This result indicated progress but fell short of our goal of 90% compliance. After 25 training sessions, problem-solving techniques were applied to help the consistently noncompliant animals become more proficient. The techniques included reducing social stress by shifting animals so that noncompliant monkeys could shift into an unoccupied space, using more highly preferred foods, and 'jackpot'-sized reinforcement. To determine whether social rank affected training success, animals were categorized into high, medium, and low dominance groups, based on 7 h of behavioral observations. A Kruskal-Wallis test result indicated a significant difference in compliance according to the category of dominance. Although training a group this large proved challenging, the mangabeys cooperated more than 90% of the time during follow-up sessions. The training program improved efficiency in caring for the mangabeys.

Habituation and desensitization as methods for reducing fearful behavior in singly housed rhesus macaques

Operant conditioning using positive reinforcement techniques has been used extensively in the management of nonhuman primates in both zoological and laboratory settings. This research project was intended to test the usefulness of counter-conditioning techniques in reducing the fear-responses of singly housed male rhesus macaques living in the laboratory environment. A total of 18 male rhesus macaques (Macaca mulatta) were selected for this project and randomly assigned to one of three groups: a desensitization training group, a husbandry training group, or a control group. Behavioral data were collected before and after a 6 weeks training and/or habituation period during which the first two groups received a total of 125 min of positive reinforcement training (and also were assumed to undergo habituation to the environment) and the control group experienced only simple habituation to the environment. Based on a Wilcoxon Matched-Pairs Sign Test, we found that a significant proportion of animals exposed to desensitization training showed a reduction in the rate at which they engaged in cringing toward humans (exact significance=0.016, one-tailed, N-ties=6), cringing in general (exact significance=0.016, one-tailed, N-ties=6), and in stress-related behaviors (exact significance=0.016, one-tailed, N-ties=6). This was not the case for animals exposed to basic husbandry training or animals in the control group. A significant proportion of desensitization-exposed animals also showed a reduction in the duration of time spent cringing toward humans (exact significance=0.016, one-tailed, N-ties=6), but not in cringing behaviors in general or in stress-related behaviors. There were not a significant proportion of animals in either the husbandry training group or the control group that showed a decrease in duration of these behaviors. Results of this study could enhance both laboratory animal welfare and laboratory animal research, and could be a first step in developing techniques for reducing fearful behavior in rhesus monkeys in the laboratory environment.

Environmental Effects on the Behavior of Zoo-housed Lions and Tigers, with a Case Study o the Effects of a Visual Barrier on Pacing

Tigers and lions in the wild are nocturnal nonhuman animals who may hunt and mate opportunistically during daylight hours. In captivity, they spend most time on exhibit sleeping or pacing. To better understand their activity budget, this study examined the daily behavior patterns of 2 Sumatran tigers and 3 African lions in different housings. The proportion of scans the large felids spent engaged in stereotypic pacing varied by time of day and environment. The tigers spent different amounts of time pacing when housed in different exhibits; the lions paced more in off-exhibit housing than when on exhibit. These differences suggest changes to the cats' immediate housing environment may decrease pacing but provide little insight into altering specifics. Carnivores' pacing relates to their inability to control sensory access to social partners. Both environments with increased pacing contained chain-link fencing. allowing uncontrolled sensory contact. Where the tigers paced, the study placed a visual barrier between one female and keepers' or conspecifics' cues. This did not significantly decrease pacing. However, the study suggests considering sensory access and environmental variables when designing environments for captive carnivores.

Relative numerousness judgment and summation in young, middle-aged, and older adult orangutans (Pongo pygmaeus abelii and Pongo pygmaeus pygmaeus)

The ability to select the larger of two quantities ranging from 1 to 5 (relative numerousness judgment [RNJ[) and the ability to select the larger of two pairs of quantities with each pair ranging from 1 to 8 (summation) were evaluated in young, middle-aged, and older adult orangutans (7 Pongo pygmaeus abelii and 2 Pongo pygmaeus pygmaeus). Summation accuracy and RNJ were similar to those of previous reports in apes; however, the pattern of age-related differences with regard to these tasks was different from that previously reported in gorillas. Older orangutans were less accurate than the young and middle-aged for RNJ, and summation accuracy was equivalent among age groups. Evidence was found to suggest that the young and middle-aged based their selection of the largest quantity pair on both quantities within each pair during the summation task. These results show a relationship between subject age and the quantitative abilities of adult orangutans.

Survey of environmental enhancement programs for laboratory primates

Animal welfare regulations in the United States require that nonhuman primate environmental enhancement plans be made in accordance with currently accepted professional standards; however, little information is available for quantifying common practice. Here we report the results of a 2003 survey that was sent to individuals overseeing enrichment programs at a variety of primate research institutions. The surveys requested information on program administration and management, implementation standards, procedures, and constraints pertaining to major categories of environmental enrichment, as well as intervention plans for animals exhibiting behavioral pathologies. Data were obtained on the management of 35,863 primates in 22 facilities. Behavioral scientists performed program oversight at the majority of facilities. Most programs reported recent changes, most commonly due to external site visits, and least commonly resulting from internal review. Most facilities' institutional animal care and use committees (IACUCs) included of individuals with behavioral expertise, and about two-thirds reported that enrichment issues could influence research protocol design. While most primates were reported to be housed socially (73%), social housing for indoor-housed primates appears to have changed little over the past 10 years. Research protocol issues and social incompatibility were commonly cited constraints. Implementation of feeding, manipulanda, and structural enrichment was relatively unconstrained, and contributions to these aspects of behavioral management generally included individuals in a wide variety of positions within a facility. In contrast, enrichment devices were used on a less widespread basis within facilities, and positive reinforcement programs that involved dedicated trainers were rare. We suggest that altering the role of the IACUC would be a productive avenue for increasing the implementation of social housing, and that an emphasis on prevention rather than intervention against behavioral pathology is warranted. The data from this survey may be useful for anticipating future program evaluations, establishing more effective internal evaluations, and assessing program progress and resource allocation.

The structure of social relationships among captive female giraffe (Giraffa camelopardalis)

Giraffe herds have been characterized as random associations of individuals, but recent evidence suggests giraffe have a more complex social structure. The authors formulated 3 hypotheses designed to evaluate whether a herd of captive giraffe (Giraffa camelopardalis) associated randomly or patterned their behavior and proximity in a manner indicative of social relationships. Affiliative interaction, proximity, and nearest neighbors for 6 captive female giraffe living in a large outdoor enclosure were analyzed, and all three measures were nonrandomly distributed, indicating female giraffe had social preferences. Furthermore, preferences were consistent across measures and time, suggesting that adult female giraffe maintain relationships. Mother-daughter pairs and pairs with large age differences between members interacted and associated most often. The social structure of this captive herd is influenced by social relationships between individual adult females, and the social behavior of individual females should be examined more closely in the wild.

Preparing chimpanzees for laboratory research

The chimpanzee is the only representative of the Great Apes that is extensively involved in biomedical research in primate laboratories. These apes are used as animal models in a variety of studies, including research on infectious disease, parasitic disease, pharmacokinetic studies, neuroscience, cognition, and behavior. Chimpanzees used in biomedical research in the United States reside largely in six specialized research and holding facilities, and most of the research with them is conducted at these sites. Given the relatively small population of chimpanzees and its importance to biomedical research, it is imperative that we carefully manage the care, production, and use of these animals in biomedical research studies. Selection criteria and preparation techniques are reviewed in this article in an effort to begin a discussion on best practices for choosing and handling chimpanzees participating in biomedical research. The use of routine health assessment information is described for subject selection, as are behavioral issues to be considered. Due to the relatively small number of chimpanzees available, issues related to experimental design and multiple uses of chimpanzees are discussed. Practices related to the transportation and acclimation of chimpanzees are described. Finally, behavioral conditioning procedures are discussed, including habituation, desensitization, and positive reinforcement training that have been applied to reduce animal distress and improve the quality of the science being conducted with chimpanzee subjects.