Active during the day, the black-shanked douc is never seen on the ground in the wild, and spends much of its time feeding high in the forest canopy. Suffering from gastric distress after eating ripe fruit, it prefers unripe fruit and young leaves, which are more easily broken down in its complex four-chambered stomach. The black-shanked douc’s water requirement is provided mostly by its food, but it will also lick the dew from leaves in the morning (2).
Travelling with between 3 and 50 individuals in a group (usually 4 – 25), the black-shanked douc is a very social primate, and individuals will readily play and groom together. Social grooming can last for up to an hour before the afternoon nap, during which pairs sleep together, as do females and their infants. Most groups are multi-male and multi-female, with more females than males, but juvenile males may disperse, forming non-breeding bachelor groups. Motherhood is a shared duty, giving females time to feed, as well as helping to integrate the young into the group. However, females in the group are occasionally aggressive towards one another. Group ranges overlap, and opposing males will threaten each other by brachiating and jumping back and forth whilst slapping their hands against their thighs. Vocalisations are rare, but threats to the group elicit loud calls and barks, and can also cause panic diarrhoea (2).
With no distinct breeding season, the female solicits mating at any time by staring intently at the male with her mouth closed and chin thrust out. Moving her head gently from side to side without lowering her gaze, the female then crouches near the male to mate. Gestation lasts for 180 to 190 days, during which time the female is not socially active, preferring to keep calm and quiet. She will continue to care for the group’s young, however, until two weeks before the birth of her own infant. Females wait between a year and three years before giving birth again. Black-shanked doucs can live for up to 30 years (2).