The doucs are colobine Old World monkeys, which make up the genus Pygathrix.

The red-shanked douc characteristically has bright maroon legs and reddish patches around the eyes.

In contrast, the grey-shanked douc is less vibrant, with speckled grey legs and orange markings on the face.

Their long hind limbs and tail allow these monkeys to be very agile in their treetop habitat.

Young males unaffiliated with a family group often make their own troops.