Destructible Toys as Enrichment for Captive Chimpanzees

Cognitive enrichment in a social setting: assessing the use of a novel food maze in sanctuary-housed chimpanzees

Foraging devices are effective enrichment tools for non-human primates, as they provide both cognitive and manipulative stimulation that may enhance these animals’ welfare. We assessed the behavioral effects of a novel tool-based enrichment on 14 chimpanzees (Pan troglodytes) housed at Fundació Mona (Girona, Spain). The device consisted of a vertical maze filled with food rewards, which chimpanzees could extract by using tools. We conducted behavioral observations in two conditions over an approximately 2.5-month period: when the food maze was loaded (12 enrichment days), and when it was empty (12 baseline days). Data were collected using 2-min scan sampling and untimed-event focal sampling during two daily sessions of 80 min each. We expected that the chimpanzees’ interest in the enrichment would decrease over time, but that its use would be linked to an increase in the occurrence of species-typical behaviors, a reduction in negative indicators of welfare, and changes in social behaviors. We found that participation widely varied among subjects, being higher in females and decreasing through time. Furthermore, participation was linked to an increase in tool use and a decrease in inactivity, but also to an increase in aggression-related behaviors. In contrast, participation had no effect on the occurrence of abnormal behaviors, social proximity or affiliation-related behaviors. Finally, we detected an increase in self-directed behaviors only when subjects actively interacted with the device. We conclude that, in future studies, these types of devices should be evaluated for longer periods of time and more attention should be paid to individuals’ preferences and abilities.

Controllability in environmental enrichment for captive chimpanzees (Pan troglodytes)

This study considers the use of nonsocial environmental enrichment by captive chimpanzees at the Primate Foundation of Arizona. The goal was to determine whether a relationship existed between controllability of enrichment items by captive chimpanzees and frequency of use. The study measured controllability, the ability of nonhuman animals to alter aspects of their environment by the potential destructibility of the enrichment item. This study examined additional factors that may affect enrichment use: individual age, sex, rearing history, social group composition, and availability of outdoor access. The chimpanzees in the study used destructible items--the enrichment category with the highest level of controllability--more than indestructible items across all age, sex, and rearing classes. Thus, controllability seems to be an important factor in chimpanzee enrichment. Younger individuals and groups with outdoor access used enrichment more than did older individuals and groups with indoor-only access. Individual sex, rearing history, and social group composition had minimal effects on enrichment use. These results support the importance of control to captive chimpanzees and further enable captive management to customize enrichment programs to the needs of particular animals.

Behavioral Management of Chimpanzees in Biomedical Research Facilities: The State of the Science

The current status of the behavioral management of chimpanzees housed in US research facilities is examined, and recent advances are described. Behavioral management includes the application of environmental enrichment, animal training, and environmental design for improving animal welfare. Authors surveyed the six major chimpanzee holding facilities and found that the vast majority of chimpanzees are housed socially, with access to the outdoors. The institutions currently invest in behavioral scientists, enrichment specialists, and, most recently, chimpanzee trainers to implement and study chimpanzee behavioral management. This review is based on the substantial scientific literature related to managing social behavior, identifying the behavioral effects of restricted socialization, evaluating various forms of enrichment, and describing positive reinforcement animal training. Authors outline recent accomplishments in behavioral management, summarize behavioral issues that have been evaluated, and identify issues for future consideration. It is proposed that the enhanced application of behavioral management techniques, including training, could significantly reduce chimpanzee stress that is generally associated with experimental manipulations, and could improve animal welfare and the quality of biomedical research. The next challenge is to implement effectively and thoroughly the approaches that have been shown to be beneficial.

Use of Temporary and Semipermanent Enrichment Objects by Five Chimpanzees

At the Chimpanzee and Human Communication Institute, caregivers provide the 5 chimpanzees who reside there with many different forms of social, food, habitat, and object enrichment. In this study, we examined the chimpanzees' use of both semipermanent and temporary objects. Semipermanent objects included cargo nets, climbing structures, a treat mound, and other objects that were present at the chimpanzees' enclosure throughout the duration of this study. Each day, 50 temporary objects were placed in the chimpanzees' outdoor enclosure or indoor exercise rooms. Frequency of use was examined in 2 conditions: rotated and same. In the rotated condition, temporary objects were replaced with different temporary objects after 3 hr. In the same condition, temporary objects were presented for the entire day. Focal and scan sampling were used to record the chimpanzees' use of enrichment objects. Observers collected focal sample data to record the chimpanzees' initial reaction to objects when entering the indoor exercise rooms, outdoor enclosures, or both at 9:00 a.m. and 1.00 p.m. A total of 35 hr of focal data and 156 hr of scan data were collected over an 8-week period. Temporary object rotation increased the overall frequency of temporary object use both in the initial 15 min of focal sample data and during the following 6 hr of scan sample data for 4 of the chimpanzees. All of these chimpanzees used both semipermanent and temporary objects throughout the day. Each chimpanzee's pattern of use was unique. The results of this study emphasize the importance of temporary object rotation and presentation of both temporary and semipermanent objects to captive chimpanzee environments.