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.

Positive reinforcement methods to train chimpanzees to cooperate with urine collection.

Positive reinforcement training can be used in many ways to enhance the welfare of captive primates. Training for biologic sample collection is one application of positive reinforcement training. In this study, 35 adult female chimpanzees were trained to cooperate with the collection of urine samples needed to facilitate a research study. A median of 35 training sessions was required for the subjects to reach reliable performance (4 of 5 sequential attempts successful) of the urine collection behavior. Adult age had no effect on the speed of learning as indicated by a rank order correlation. Individual differences in the rate of learning were pronounced but did not vary with the age of the chimpanzees. Approximately 2 y after the initial training, and with continual sample collection taking place twice weekly, we assessed the reliability of their performance and found that the chimpanzees cooperated 100% of the time and that collection of a urine sample required about 5 min. Positive reinforcement training can markedly reduce staff time, particularly for studies such as this that require frequent biologic sample collection over long durations. Similar approaches could be used to train other laboratory primates to cooperate with urine collection procedures. Animal training programs that emphasize positive reinforcement training are an important refinement in the care of laboratory primates.