The goal of environmental enrichment is to stimulate captive animals to behave in a manner similar to their wild counterparts. This is the first study to examine systematically how activity budgets and feeding behavior of Japanese macaques are affected by enclosure type. A systematic study was conducted on three captive groups, one in a naturally forested enclosure and two in non-vegetated enclosures. The forested enclosure stimulated primates to extend their feeding time and also greatly enhanced the variability of their overall feeding behavior and served as an important source of nutritional supplementation. The forest allowed immatures to access natural food sources unobtainable by adults, compared to their counterparts in the non-vegetated enclosures, allowing all individuals to pursue their own foraging needs. This book is an important monograph, invaluable for zoos and research facilities contemplating ways of improving the psychological and physical lives of their primate collection. This book describes in a clear, scientifically systematic way, the benefits of a successes environmental enrichment program.