O'Neill, P. L., Price, C., Suomi, S. J. 1990. Designing captive primate environments sensitive to age and gender related activity profiles for rhesus monkeys (Macaca mulatta). American Zoo and Aquarium Association (AZA) Regional Conference Proceedings, 346-354.

An analysis of the time budget (agonistic behavior is excluded) of rhesus macaque groups kept in free-ranging and confined [corncrib] condition. Adult animals spent about the same amount of time engaged in social grooming in both conditions (17%) but spent more of the time sleeping (6.6% vs 2.9%) and foraging (5.9% vs 1.3%) in the free-ranging condition than in the confined condition.