Allen’s swamp monkey lives in swamp forests in the lowlands of the Congo Basin. It searches for food in trees, on the ground and in shallow water.
It has a small, stout body and brown, gray or greenish fur that is longer around the neck and shoulders. Its tail is generally longer than its body.
It is active by day and eats fruit, seeds, insects, fish, shrimp and other small animals. Although it spends much of its time in trees, it also forages on the ground and in shallow water.
An extinction-risk assessment has not been added yet.