Red howling monkey use of specific defecation sites as a parasite avoidance strategy.

Red howling monkeys, Alouatta seniculusin the central Amazonian basin move to specific sites before defecating. Differences in the vegetation profile of behavioural sites, defecation sites and random sites within the ranging area of howler groups were examined. The defecation sites used differed in the number of leaf intercepts at the levels of the forest the monkeys used for foraging and travelling. Defecating in areas free of underlying vegetation decreases the likelihood of contaminating potential food sources or arboreal pathways. This defecation behaviour may be an important parasite avoidance strategy of red howling monkeys.