The Allen's swamp monkey is a primate species that belongs to the Old World monkey family. Allen's swamp monkeys were named after american zoologist Joel Asaph Allen. They are strongly built animals. Their skin is grey-green at the top side. The face is reddish with long hair bundles at the cheeks. Fingers and toes of these monkey are slightly webbed which points to their partially aquatic way of life. Males in this species are noticebly larger than the females.
Allen's swamp monkeys live in the Congo Basin, in the Republic of Congo, Cameroon and in the west of the Democratic Republic of the Congo (DRC). They occur in swamp forest and riverine habitat.
Allen's swamp monkeys are diurnal and semi-terrestrial animals. They regularly look for food on the ground. These monkeys inhabit swampy, water-rich areas and can swim well, diving to avoid danger. They live in social groups that consist of up to 40 animals. In order to communicate with each other they use different calls, gestures, touches and different displays of body language.
Little is known about the mating system and reproductive behavior of Allen's swamp monkeys. Females give birth to a single infant. Young are nursed during three months and become reproductively mature after three to five years.
Allen's swamp monkeys are threatened by hunting for their meat.
The IUCN Red List and other sources don’t provide the number of Allen's swamp monkey total population size. Currently this species is classified as Least Concern (LC) on the IUCN Red List