Allen’s swamp monkey

Scientific name:

Allenopithecus nigroviridis

Range and habitat:

Allen’s swamp monkeys live in the primary lowland swamp forests of northeastern Congo, Zaire, and Angola, Africa.

Natural diet:


This species feeds primarily on fruit, small amounts of roots, flowers, nectar, insects, worms and fish. People have also seen them scooping fish from small pools.

Zoo diet:

Fruit, vegetables and root vegetables, as well as lettuce and monkey chow. 

Size / weight range:

Swamp monkeys grow to 17 - 18 inches tall, with tails 19 - 20 inches long. Males weigh up to 13 pounds, while females weigh up to 8 pounds.

Social structure:


Usually one dominant adult male with several females and their offspring—the group could have up to 40 animals! Their gestation is about 5-6 months and they mature at 3-5 years old, living into their early 20s.

Location at the Toledo Zoo:

Primate Forest
You might also see the swamp monkeys live on the Primate Cam by visiting our Animal Web Cams page

Conservation Status:

Near Threatened - due to habitat destruction and being hunted for meat.

Interesting facts:


We have one female (Tilly- born in 1998) and one male (Mapenzi- born in 2005). Females are noticeably smaller than males in this species (a characteristic known as sexual dimorphism), with rounder heads than the males’ larger, flatter foreheads. Swamp monkeys are the only species in their genus.

These monkeys can swim! Especially when we have young animals in the group, we have seen them holding their breath and doing laps underwater (slight webbing between their fingers and toes helps). They also dive underwater to get food.

Swamp monkeys are curious and destructive. We don’t give them stuffed animals for enrichment because they will take out the stuffing. They also try to take apart furniture and their exhibit. Because they can unscrew nuts and bolts, we hammer the ends of any bolts we use in the exhibit so they can’t take it apart. They enjoy digging and pulling up grass to look for bugs.

When angry or threatened, swamp monkeys bob their heads and/or open-mouth threaten.

Swamp monkeys have cheek pouches that they use to store food. This enables them to gather food and eat it later at their leisure when there is no competition.