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A male drill with dark fur and a colorful rump walking on the forest floor.
Photo: Bernard DUPONT from FRANCE, CC BY-SA 2.0, via Wikimedia Commons

Drill

Mandrillus leucophaeus

An endangered baboon relative of West-Central African rainforests whose males have a bright red chin and a mane.

🐒 Monkeys
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About the Drill

Drills live only in large, undisturbed lowland rainforests in Cameroon, Nigeria and the island of Bioko. Males weigh 80 to 110 pounds, much more than females at 30 to 45 pounds. Drills eat mostly plants and some small invertebrates. They can store food in cheek pouches that hold as much as their stomachs. Troops of 20 or more are led by one dominant male.[1]

Quick facts

Scientific name
Mandrillus leucophaeus[1]
Weight
Males 80 to 110 pounds. Females 30 to 45 pounds.[1]
Lifespan
About 20 years in the wild. Up to 46 in a zoo.[1]
Diet
Mostly plants, plus small invertebrates.[1]
Habitat
Large, undisturbed lowland rainforest.[1]
Where it lives
West-central Africa: Cameroon, Nigeria and the island of Bioko.[1]
Group life
Troops of 20 or more with one dominant male.[1]
Babies
Pregnancy lasts 5.5 to 6 months. Usually one baby.[1]
Conservation status
Endangered (IUCN Red List, assessed 2017).[2]

Fun facts

  • A drill's cheek pouches can hold as much food as its stomach.[1]
  • The red on a drill's rump comes from blood vessels near the skin, not from pigment.[1]
  • Male drills have canine teeth 1.5 to 2 inches long.[1]

Vocabulary

troop
A group of monkeys or other primates that live together.
groom
To clean another animal's fur, which also builds friendships.
cheek pouch
A stretchy pocket inside the cheek used to carry food.
bushmeat
Meat from wild animals hunted for food or sale.
endangered
A conservation label meaning a species faces a very high risk of dying out in the wild.

See it in person

Sources

  1. [1] Zoo Atlanta. “Drill.” https://zooatlanta.org/animal/drill/ (accessed 2026-10-02)
  2. [2] IUCN Red List of Threatened Species. “Mandrillus leucophaeus (Drill).” https://www.iucnredlist.org/species/12753/17952490 (accessed 2026-10-02)

Facts last checked 2026-10-02.

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