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

primate Primates is an order (biology), order of mammals, which is further divided into the Strepsirrhini, strepsirrhines, which include lemurs, galagos, and Lorisidae, lorisids; and the Haplorhini, haplorhines, which include Tarsiiformes, tarsiers a ...

of the family

Cercopithecidae Old World monkeys are primates in the family (biology), family Cercopithecidae (). Twenty-four genus, genera and 138 species are recognized, making it the largest primate family. Old World monkey genera include baboons (genus ''Papio''), red colo ...

(Old World monkeys), related to

baboon Baboons are primates comprising the biology, genus ''Papio'', one of the 23 genera of Old World monkeys, in the family Cercopithecidae. There are six species of baboon: the hamadryas baboon, the Guinea baboon, the olive baboon, the yellow ba ...

s and even more closely to the

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 Sexual dimorphism, sexually ...

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 sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

in weight, with males weighing up to and females up to .ARKive
Drill (''Mandrillus leucophaeus'')
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 Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

of drill are accepted by some authorities, but are not considered distinct by others:Primate Info Net
Drill
/ref> *

Mainland drill The mainland drill (''Mandrillus leucophaeus leucophaeus'') is a subspecies of the endangered drill. It is distinguished by ringed yellow and black coloring on its crown, and is otherwise similar to the Bioko drill The Bioko drill (''Mandrillu ...

, ''Mandrillus leucophaeus leucophaeus'' *

Bioko drill The Bioko drill (''Mandrillus leucophaeus poensis'') is a subspecies of the Drill (animal), drill, an Old World monkey. It is endemic to Bioko, Bioko Island, Equatorial Guinea, located off the west coast of Africa. The drill is one of the largest ...

, ''Mandrillus leucophaeus poensis'' Their closest relative is the

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

Equatorial Guinea Equatorial Guinea, officially the Republic of Equatorial Guinea, is a country on the west coast of Central Africa. It has an area of . Formerly the colony of Spanish Guinea, its post-independence name refers to its location both near the Equ ...

(Rio Muni),

Gabon Gabon ( ; ), officially the Gabonese Republic (), is a country on the Atlantic coast of Central Africa, on the equator, bordered by Equatorial Guinea to the northwest, Cameroon to the north, the Republic of the Congo to the east and south, and ...

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 ...

, 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 Cross River State is a state in the South-South geopolitical zone of Nigeria. Named for the Cross River, the state was formed from the eastern part of the Eastern Region on 27 May 1967. The state has its capital as Calabar and is bordered to ...

Nigeria Nigeria, officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf of Guinea in the Atlantic Ocean to the south. It covers an area of . With Demographics of Nigeria, ...

, southwestern

Cameroon Cameroon, officially the Republic of Cameroon, is a country in Central Africa. It shares boundaries with Nigeria to the west and north, Chad to the northeast, the Central African Republic to the east, and Equatorial Guinea, Gabon, and the R ...

(south to the

Sanaga River The Sanaga River (formerly ) is the largest river in Cameroon located in East Region (Cameroon), East Region, Centre Region (Cameroon), Centre Region and Littoral Region (Cameroon), Littoral Region. Its length is about from the confluence of Dj ...

), and on

Bioko Bioko (; ; ; historically known as Fernando Pó, ) is an island of Equatorial Guinea. It is located south of the coast of Cameroon, and northwest of the northernmost part of mainland Equatorial Guinea. Malabo, on the north coast of the is ...

Island, part of

, in

rainforest Rainforests are forests characterized by a closed and continuous tree Canopy (biology), canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropi ...

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 or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

, 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