In natural environments, the chance of obtaining foods are not stable and many animals spend most of their times for searching foods and feeding. In captivity, however, they are foraged with fixed feeding schedules and stable amounts of foods. This can be said to be boredom and not welfared environment for captive wild animals. With the technique of environmental enrichment, if varying the feeding schedules and the amounts of foods let wild animals in captivity express their natural behaviours, it can be evaluated to realize the animal welfare. In this study, the modification of behaviours and social relationships on a group of 7 tufted capuchin monkeys (Cebus apella) of Yumemigasaki zoological park in Kawasaki, Japan was examined with the varied intervals and ratios schedules of feeding; total amounts of foods per day was fixed but the inter-feeding intervals, 0.5, 1, 1.75, 2.5 and 5 hrs., and the amount of food in each inter-feeding intervals, 0.36, 0.65, 0.98, 1.3 and 1.96 kg, were varied randomly in intra and inter day. Data collections were carried out 6 hours per day, 9:30-15:30, with observation and recording methods of focal animal sampling of 10 minutes per animal and 10 second one-zero sampling for recording behaviors. Experiments were done from October 3rd to November 5th in 2007. The modification of behaviours and social relationships on subjected animals in each inter-feeding intervals conditions will be presented.
