A captive group of white-faced capuchins, Cebus capucinus, was presented with four deep litters in simultaneous choice (or preference) tests. A floor covering of ground corn cob, woodchips, wood wool or peat was presented once in each quarter of the group's indoor floor-area
for 14 consecutive days, and the layout of the litters was rotated after each such period. The monkeys were observed on 10 days in each period to determine the occurrence of locomotion, foraging. play, and social contact on each of the litters. The ground corn cob was clearly the least attractive
floor covering for the monkeys, while peat and wood wool proved to be the most attractive. Most instances of social contact occurred on the peat, due to the occurrence of communal peat-bathing, while wood wool afforded the most play. The provision of different litter types in different areas
of the indoor enclosure is a simple means of promoting a greater range of natural activities in captive primates, and probably also in other animals.