The slight webbing of the fingers and toes point to its partially aquatic way of life.

Allen's swamp monkey can reach a full body length from 45 to 60 cm, with a roughly 50-cm-long tail.

Allen's swamp monkey is a diurnal animal and regularly looks for food on the ground.

It lives in social groups of up to 40 animals, communicating with different calls, gestures, and touches.

Raptors, snakes, and the bonobo are the natural predators of Allen's swamp monkey.