Katherine E. Wagner

Ape behavior in two alternating environments: comparing exhibit and short-term holding areas.

In many facilities, primates are voluntarily transferred between different enclosures on a daily basis to facilitate animal husbandry and exhibit maintenance. This procedure is particularly relevant in the management of great apes living in zoos, where the requirements of functional management must be balanced with the desire to maintain enriching and naturalistic exhibit enclosures that benefit ape residents and attract the visiting public. In these settings, examinations of ape behavior and welfare typically focus exclusively on activity in the primary exhibit area. However, physical, social and sensory experiences unique to each area may shape different patterns of behavior. In the current study, zoo‐living chimpanzees and gorillas were moved each day from exhibit areas to off‐exhibit holding areas for a short duration as a part of regular management procedures. Behavioral data indicated species‐specific reactions to the holding area, including increased aggression and self‐directed behavior by chimpanzees and increased activity and prosocial behavior among gorilla subjects. Both species showed more feeding‐foraging behavior while in the exhibit enclosure. Results suggest that holding areas may not meet all behavior needs of captive great apes and demonstrate the importance of including all components of the captive enclosure in comprehensive analyses of great ape behavior and welfare. Am. J. Primatol. 72:951–959, 2010.

Transfer and Acclimatization Effects on the Behavior of Two Species of African Great Ape ( Pan troglodytes and Gorilla gorilla gorilla ) Moved to a Novel and Naturalistic Zoo Environment

Studying the effects of moving animals to new enclosures is of value to both captive managers and to scientists interested in the complex interplay between environment and behavior. Great apes represent some of the greatest challenges in this regard. Given the cognitive sophistication of these species and the substantial investments in new primate facilities, these investigations are particularly important. Using post-occupancy evaluation (POE) methodology, we compared behavior exhibited by chimpanzees (Pan troglodytes) and gorillas (Gorilla gorilla gorilla) in indoor hardscape-type exhibits to behavior of the same individuals in new naturalistic enclosures with outdoor access. In the new facility, chimpanzees showed decreases in the frequency of abnormal behaviors and visual monitoring of humans (attention behaviors) whereas gorillas exhibited reduced agonism as well as decreased attention behaviors. Both gorillas and chimpanzees demonstrated higher rates of inactivity after transfer to the new facility. All subjects in addition demonstrated transitory changes in behavior after the move to the new facility (higher rates of scratching in yr 1 than in subsequent years), indicating a period of acclimatization. Seasonal effects on feeding behavior and activity levels (both species were more active in the winter) were evident as well. The results indicate that behavioral adjustment to a new facility is an extended process for both species and that seasonal effects should be considered in longitudinal analyses of acclimatization. Behavioral patterns supported the benefits of naturalistic, functional exhibit spaces and the utility of post-occupancy evaluations in assessing captive animal welfare.

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.

Evaluating the physiological and behavioral response of a male and female gorilla (Gorilla gorilla gorilla) during an introduction

Prolonged stress responses can lead to infertility and death; therefore monitoring respective indicators like stress-related hormones and behaviors is an important tool in ensuring the health and well-being among zoo-housed animal populations. Changes in social structure, such as the introduction of a new conspecific, can be a source of stress. In April 2010, a sexually mature female western lowland gorilla (Gorilla gorilla gorilla) was brought to Lincoln Park Zoo (LPZ; Chicago, IL) from the Chicago Zoological Park (Brookfield, IL) for a breeding recommendation from the Gorilla Species Survival Plan. Fecal glucocorticoid metabolites (FGMs) were monitored in two gorillas prior to, during and immediately following the social introduction. Reproduction events, such ovarian cyclicity and pregnancy, were monitored using behavior and fecal progestagen metabolite (FPM; female) and fecal androgen metabolite (FAM; male) analyses. Mean (± standard error) FGM concentrations for the male were elevated (P = 0.002) during the introduction (20.61 ± 0.83 ng/g) compared to the pre- and post-introduction phases (11.31 ± 0.48 ng/g and 12.42 ± 0.65 ng/g, respectively). For the female, mean FGM concentrations were lower (P < 0.001) during the post-introduction (17.91 ± 1.07 ng/g) than during the pre- and introduction phases (30.50 ± 3.42 and 27.38 ± 1.51 ng/g, respectively). The female maintained normal FPM cyclicity throughout the study and became pregnant in the post-introduction phase. These results suggest the importance of both behavioral and physiological monitoring of zoo animals and demonstrate the potential stress that can occur during social introductions. Zoo Biol. 33:394-402, 2014.

Social Models Enhance Apes' Memory for Novel Events.

Nonhuman primates are more likely to learn from the actions of a social model than a non-social “ghost display”, however the mechanism underlying this effect is still unknown. One possibility is that live models are more engaging, drawing increased attention to social stimuli. However, recent research with humans has suggested that live models fundamentally alter memory, not low-level attention. In the current study, we developed a novel eye-tracking paradigm to disentangle the influence of social context on attention and memory in apes. Tested in two conditions, zoo-housed apes (2 gorillas, 5 chimpanzees) were familiarized to videos of a human hand (social condition) and mechanical claw (non-social condition) constructing a three-block tower. During the memory test, subjects viewed side-by-side pictures of the previously-constructed block tower and a novel block tower. In accordance with looking-time paradigms, increased looking time to the novel block tower was used to measure event memory. Apes evidenced memory for the event featuring a social model, though not for the non-social condition. This effect was not dependent on attention differences to the videos. These findings provide the first evidence that, like humans, social stimuli increase nonhuman primates’ event memory, which may aid in information transmission via social learning.

Chimpanzee (Pan troglodytes) birth patterns and human presence in zoological settings.

In response to work demonstrating a negative correlation between human staff activity and parturition in laboratory‐managed primates, this study examined the distribution of 231 captive chimpanzee (Pan troglodytes) births that occurred in accredited American zoological institutions by the day of the week on which the birth was discovered. We hypothesized that if chimpanzee parturition patterns displayed sensitivity to human presence, then fewer births per day would be reported during the weekend period, when the visitor density was high, as compared with the lower density working week. Analyses indicated that chimpanzee births were randomly distributed throughout the week. In the context of the questionable sensitivity of primate parturition to external influence, results suggest that variations in human presence do not affect the fine‐level timing of birth in chimpanzees managed in a zoological setting. Am. J. Primatol. 70:703–706, 2008.