Hannibal, D., Cassidy, L., Day, A. et al. 2013. Increased produce enrichment reduces alopecia in captive outdoor socially-housed rhesus macaques (Macaca mulatta). American Journal of Primatology 75(S1), 92. (36th Meeting of the American Society of Primatologists Scientific Program, Abstract #195)

Alopecia is relatively rare in wild primates but more frequent in captive settings. We investigate whether increasing the quantity and variety of produce enrichment reduces alopecia. Alopecia was scored bimonthly from September 2011 through mid-November 2012 for eight social groups assigned to three conditions: controls freely offered regular produce (fruit and non-leafy vegetables) one per week (n=55), treatment of regular produce plus one day of leafy greens in an enrichment device (n=60), and treatment of regular produce plus one day of freely-available leafy greens (n=47). The best fit model includes reproductive season, leafy greens (no/yes), and an interaction term (next best model: ∆AIC=3.61). This model includes a treatment variable that combined the leafy greens categories and was a better fit than the model including reproductive season, leafy greens (no/device/free), and an interaction term (∆AIC=14.3). There are significant differences by reproductive season, with lowest alopecia scores in early breeding season, increasing through late breeding season (β=.44, p<0.001), peaking during birth season (β=.58, p<0.001), dropping early summer (β=.25, p<0.001) and lowest again next early breeding season (β=0.04, p=0.451). Alopecia is lower in the treatment group during late breeding (β=-.29, p<0.001) and birth (β=-.10, p=0.081) seasons. These results suggest that increasing the variety and frequency of enrichment produce can reduce alopecia problems in captive rhesus with or without the use of enrichment devices to increase foraging effort.