Cage-size effects on locomotor, grooming and agonistic behaviours of the slow loris, Nycticebus coucang (Primates, Lorisidae)

Abstract

Slow lorises were housed in male-female pairs under 2 experimental conditions. One pair was kept in a 0.42-m 3 cage and a second pair was allowed the run of an 8.75-m 3 walk-in cage. During Phase Ia, each pair was intermittently observed directly or by video monitor over several months so that 5 composite “days” (spanning the 12-hour active period) of behavioural data were obtained. Phase Ib, a 3-day continuous monitoring of the behaviour of each pair, followed Phase Ia. The pairs were then switched (Phase II) so that the pair originally in the walk-in cage was now in the small cage and the pair in the small cage was now in the walk-in cage. Phase IIa and IIb were methodologically identical to Phases Ia and Ib, respectively. Animals in the walk-in cage showed significantly higher amounts of locomotion than they did in the small cage, but differences in allo- and auto-grooming amounts, and in amounts of agonistic behaviour, were not correlated with cage size. Recommendations for cage sizes depend upon the uses for which the animal is being kept. Results of the experiments in this study indicate that slow lorises kept in larger cages will be more active than those housed in cages approaching recommendations for size proposed by the U.S. National Research Council. Serious consideration of the effects of reduced activity on the animal must be made in determination of cage size.