The drill (''Mandrillus leucophaeus'') is a

primate Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...

of the family

Cercopithecidae Old World monkey is the common English name for a family of primates known taxonomically as the Cercopithecidae (). Twenty-four genera and 138 species are recognized, making it the largest primate family. Old World monkey genera include baboons ...

(Old World monkeys), related to

baboon Baboons are primates comprising the genus ''Papio'', one of the 23 genera of Old World monkeys. There are six species of baboon: the hamadryas baboon, the Guinea baboon, the olive baboon, the yellow baboon, the Kinda baboon and the chacma ba ...

s and even more closely to

mandrill The mandrill (''Mandrillus sphinx'') is a large Old World monkey native to west central Africa. It is one of the most colorful mammals in the world, with red and blue skin on its face and posterior. The species is sexually dimorphic, as males ...

Description

The drill is a short-tailed monkey up to long, similar in appearance to the mandrill, but lacks the bright blue and red on the face of that species. It has high

sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

in weight, with males weighing up to and females up to .ARKive
Drill (''Mandrillus leucophaeus'')
Penetrating Gaze (18022189239)

The body is overall a dark grey-brown. Mature males have a pink lower lip and white chin on a dark grey to black face with raised grooves on the nose. The rump is pink, mauve and blue. Female drills lack the pink chin.

Taxonomy

Two

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

of drill are accepted by some authorities, but are not considered distinct by others:Primate Info Net
Drill
/ref> * Mainland drill, ''Mandrillus leucophaeus leucophaeus'' * Bioko drill, ''Mandrillus leucophaeus poensis'' Their closest relative is the

(''Mandrillus sphinx''), found from southern Cameroon through mainland

Equatorial Guinea Equatorial Guinea ( es, Guinea Ecuatorial; french: Guinée équatoriale; pt, Guiné Equatorial), officially the Republic of Equatorial Guinea ( es, link=no, República de Guinea Ecuatorial, french: link=no, République de Guinée équatoria ...

(Rio Muni),

Gabon Gabon (; ; snq, Ngabu), officially the Gabonese Republic (french: République gabonaise), is a country on the west coast of Central Africa. Located on the equator, it is bordered by Equatorial Guinea to the northwest, Cameroon to the north ...

and into the Congo. The two species are

allopatric Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...

across the Sanaga River.

Biology

A dominant male leads a multi-male multi-female group of 20-30 individuals, and is father to most of the young. This group may join others, forming super groups of over 100 individuals. They are seasonally semi-nomadic, and will often rub their chests onto trees to mark their territory. They are semi-terrestrial, foraging mainly on the ground, but climbing trees to sleep at night. The females give birth to a single baby; twins have been recorded once at the Drill Rehab & Breeding Center in Nigeria. The average longevity in captivity is 28 years. The diet is primarily

frugivorous A frugivore is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. Frugivores are highly dependent on the abundance and ...

, taking a wide range of fruit, but they also eat herbs, roots, eggs, insects, and small mammals on occasion.

Distribution

Drills are found only in

Cross River State ) , image_map = Nigeria - Cross River.svg , map_alt = , map_caption = Location of Cross River State in Nigeria , coordinates = , coor_pinpoint ...

Nigeria Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf o ...

, southwestern

Cameroon Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the C ...

(south to the

Sanaga River The Sanaga River (formerly german: Zannaga) is the largest river in Cameroon located in East Region, Centre Region and Littoral Region. Its length is about from the confluence of Djérem and Lom River. The total length of Sanaga-Djérem Rive ...

), and on

Bioko Bioko (; historically Fernando Po; bvb, Ëtulá Ëria) is an island off the west coast of Africa and the northernmost part of Equatorial Guinea. Its population was 335,048 at the 2015 census and it covers an area of . The island is located of ...

Island, part of

, in

rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...

habitats. Their entire global range is less than 40,000 km².

Conservation

Drills are among Africa’s most endangered mammals, and are listed by the IUCN as the highest conservation priority of all African primates. Drill numbers have been declining in all known habitat areas for decades as a result of illegal commercial hunting,

habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

, and human development; as few as 3,000 drills may remain in the wild, with the highest population estimate only 8,000. A total of 174 drills recovered from illegal capture are in semicaptivity at the Drill Rehabilitation and Breeding Centre in Nigeria, with high success rates in breeding recorded there,the Drill Rehabilitation and Breeding Centre (Pandrillus) Buanchor
and about 40 in other zoos internationally.

References

External links

Pandrillus
- Drill and primate conservation group operating in Nigeria and Cameroon
The Limbe Wildlife Centre (LWC)
- A wildlife rescue and rehabilitation project situated in the South West Region of Cameroon. {{Taxonbar, from=Q221434 Mandrillus Primates of Africa Mammals of Cameroon Mammals of Equatorial Guinea Mammals of West Africa Fauna of Bioko Mammals described in 1807 Taxa named by Frédéric Cuvier