Allen’s Swamp Monkeys

Allenopithecus nigroviridis

At the Detroit Zoo

Two unrelated Allen’s swamp monkeys, Azizi and Pepper, joined the Detroit Zoo in July 2022. Azizi, a male, was born March 18, 2013, while female Pepper was born Feb. 10, 2017. These highly social primates originate from the lowland forests of the Congo basin, where they inhabit swamps and riverine areas.



Known for being small and stout, Allen’s swamp monkeys can reach up to 20 inches tall and weigh up to 13 pounds. Their fur is generally brown, gray and green, and their tails are often longer than their bodies.

Fun Facts

  • While many monkey species cannot swim, Allen’s swamp monkeys have webbed feet that make them excellent swimmers. 

  • This species is largely arboreal, spending much of their lives in the trees. However, the monkeys occasionally come to the ground to forage for food. 

  • Swamp monkeys are highly social, living in groups of up to 40 in the wild. They use a variety of calls and gestures, such as deep grunts and chirp-like sounds, to communicate with other members of their group.