EFFECTS OF PREDICTABLE VERSUS UNPREDICTABLE FEEDING SCHEDULES ON CHIMPANZEE BEHAVIOR

One factor not often studied in the design of feeding enrichment programs is the timetable according to which enrichments are offered. This study was performed to lend a quantitative basis to primate colony management decisions concerning feeding schedules, The objective was to determine whether feeding fresh produce meals on a predictable schedule was preferable to doing so on an unpredictable schedule from the perspective of promoting psychological well-being of chimpanzees, The subjects were 30 adult or adolescent chimpanzees (Pan troglodytes) living in four different social groups. Feeding practices were changed to a more unpredictable schedule for two of these groups, 5 or 6 months prior to the initiation of data collection; feeding of the other two groups continued on a more predictable schedule, The predictable meal was always fed within a 30 min period and the unpredictable meal was fed within a 150 min period, Observational data were collected during prefeeding and baseline periods. A mixed model multivariate analysis of variance for repeated measures revealed that inactivity was more prevalent in the prefeeding period for the chimpanzees fed on the predictable schedule than in the other study phases, and abnormal behavior showed a similar trend. These findings indicate that feeding on a more unpredictable schedule may lead to increased species-appropriate behavior, The scheduling of animal care routines deserves closer attention from those conducting research on improving care and well-being of captive primates.