The Drill

The Drill (Mandrillus leucophaeus) is a primate of the Cercopithecidae (Old-world Monkeys) family, closely related to the baboons and even more closely to the Mandrill.

The Drill is similar in appearance to the Mandrill, but lacks the colorful face. They are semi-terrestrial monkeys, exhibiting extreme sexual dimorphism with males weighing up to 100lbs (45.35 kg) - three times the size of females. They are semi-nomadic seasonally and little is known of their behavior or ecology in the wild.

Drills are found only in Cross River State, Nigeria; South Western Cameroon; and on Bioko Island, part of Equatorial Guinea. Their entire world range is less than 40,000 km2, smaller than Switzerland.

Drills are among Africa’s most endangered mammals, and are listed by the IUCN as the highest conservation priority of all African primates.[2] Drill numbers have been declining in all known habitat areas for decades as a result of illegal commercial hunting, habitat destruction, and human development: as few as 3,000 drills may remain in the wild, the highest population estimate is 8,000. Drills have also been declining in zoos internationally.

There are two subspecies of Drill:

* Mainland Drill, Mandrillus leucophaeus leucophaeus
* Bioko Drill, Mandrillus leucophaeus poensis

Their closest relative is the mandrill (Mandrillus sphinx), found from southern Cameroon through mainland Equatorial Guinea (Rio Muni), Gabon and into Congo. The two species are allopatric across the Sanaga River.