Behavioral effects of perches on group-housed adult female Japanese monkeys

The use of perches to enrich the environment of group-housed Japanese monkeys (Macaca fuscata) was assessed. When monkeys were housed in a cage which contained eight wooden perches to increase the usable space, the rate of agonistic interactions as well as the rates of spatial proximity and social grooming decreased in comparison with those evident when they were housed in a cage without such perches. These results suggest that agonistic interactions were reduced which are likely to occur more frequently in crowded conditions and the monkeys displayed affiliative behavior such as social grooming more frequently in a cage without perches, i.e., more crowded conditions, than in a cage with perches. Attempts to enrich the environment of group-housed monkeys may lead to a better understanding of their behavioral flexibility and social adjustment.