Short and long-term effects of a substantial change in cage size on individually housed, adult male rhesus monkeys (Macaca mulatta) (2004)

Kaufman, B. M., Pouliot, A. L., Tiefenbacher S. et al.

Abstract

We investigated the effects of a six-fold increase in cage size on the behaviour of individually housed male rhesus monkeys. ... Prior to this study, eight male monkeys were individually housed in pens (6.77 m3) for varying lengths of time before moving to baboon cages (1.24 m3) located within their pens. After 2 years in baboon cages, monkeys were returned to their pen environment (6.77 m3). Monkeys were observed for forty 5 min observation periods representing four phases: short (first 4 months) and long-term (after 23 months) exposure to the baboon cage followed by short (first month) and long-term (after 8 months) exposure to the pen environment. Contrary to expectations, general activity decreased and abnormal behaviour remained unchanged when the monkeys were returned to their pens. However, tension-related behaviour decreased significantly with exposure to a larger cage.