Comparing the effectiveness of PVC perches versus wooden perches as environmental enrichment objects for singly caged rhesus monkeys (1990)

Reinhardt, V.

Abstract

One half of each cage was provided with a PVC pipe, the other with an oak branch. Both perches had the same diameter and were installed in the same manner. During one-hour observation sessions, single-caged subjects showed no clear preference but spent on average 19% of the time on the PVC pipe and another 24% of the time on the oak branch.