Andrews, K., Morelli, N., Ruesterholz, E. et al. 2012. The use of bedding for groups of rhesus macaques. American Journal of Primatology 74(S1), 69. (35th Meeting of the American Society of Primatologists Scientific Program, Abstract #138)

The use of substrate can have benefits to group housed macaques, including decreased aggression and increased foraging. Still, in some facilities, the use of bedding is perceived as time intensive and costly. In this study, we examined the use of wood shavings on husbandry issues (e.g., time for cleaning) and behavior in outdoor environmentally controlled housing units over a one month period. Each unit was 1400 square feet and contained 30-50 rhesus macaques (Macaca mulatta). We put pine shavings in 4 housing units, a mixture of pine and aspen shavings in 4, and left 4 units without bedding. We compared the time it took to clean the units, as well as water use. We also took daily focal observations in 2 randomly selected adult females per group. There were no differences between the groups with the pine and pine/aspen shaving. Overall, it took significantly more time and water to clean the non-bedded units compared to those with bedding (Time: Kruskal-Wallis H= 7.3, p=0.03; Water: H=7.0, p=0.03). While all groups received enrichment devices designed to promote foraging, animals in groups with substrate spent more time foraging compared to those without (H=17.3, p<0.001). Animals in bedded units also engaged in less self-grooming than those in units without bedding (H=8.9, p=0.01). Bedding can be a cost-effective form of enrichment for group-housed macaques.