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Drill
Mandrillus

Conservation status:
Endangered (M. leucophaeus), Vulnerable (M. sphinx)

Life span: ~40 years (captive)
Total population: Unknown
Regions: Cameroon, Equatorial Guinea, Gabon, Nigeria, Republic of Congo
Gestation: M. leucophaeus: 179-182 days; M. sphinx: 175 days
Height: Unknown
Weight: M. leucophaeus: 32.3 kg (M), 11.7 kg (F); M. sphinx: 31.6 to 33.0 kg (M), 12.0 to 12.9 kg (F)

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TAXONOMY

Suborder: Haplorrhini
Infraorder: Simiiformes
Superfamily: Cercopithecoidea
Family: Cercopithecidae
Subfamily: Cercopithecinae
Genus: Mandrillus
Species: M. leucophaeus, M. sphinx

Other names: M. leucophaeus: Papio leucophaeus, drill; drill (Danish, Dutch, French, German, Spanish, Swedish); Drilli (Finnish); drillo (Italian); dril (Spanish); M. sphinx: Papio sphinx, mandrill; mandrill (Danish, French, German, Swedish); mandril (Dutch); mandrillit (Finnish); mandrillo (Italian); mandril (Spanish).

There are two monotypic species in the genus Mandrillus, the mandrill (M. sphinx) and the drill (M. leucophaeus), each with no subspecies (Groves 2005). For clarity, they will each be referred to here by their scientific names as opposed to their common names.

MORPHOLOGY

M. leucophaeus
M. leucophaeus
Photo: Verena Behringer

Members of the genus Mandrillus are large-bodied primates that are instantly recognizable. M. sphinx have thick dark gray pelage, banded in black and reddish-yellow, while M. leucophaeus are greenish gray or brown overall with a whitish belly (Groves 2001; Ankel-Simons 2007). M. sphinx have an orange beard, while M. leucophaeus have a white beard (Groves 2001). The hairless face however, holds the most profound differences between the species. The face of M. sphinx is immediately recognizable, featuring an elongated snout with swollen blue ridges on top (4 or 5) and red nose and lips (Groves 2001; Ankel-Simons 2007). Female M. sphinx have far more subdued coloration in the face than do males, but can range from black to bright pink (Cousins 1984; Setchell et al. 2006). M. leucophaeus differ in their facial coloration, which is more subdued than in M. sphinx. Their lower lip is red, but the rest of the face is entirely shiny black, with smooth swollen ridges on the top of the elongated snout (Hill 1955; Groves 2001). There is a ruff of white hair around the face in M. leucophaeus (Cousins 1984). Male M. leucophaeus have red and blue colored anogenital regions, while male M. sphinx have strikingly multi-colored (red, pink, blue, scarlet, and purple) anogenital areas (Ankel-Simons 2007). All sexes and species of Mandrillus have pale pink ischial callosities (Ankel-Simons 2007). Individuals of the genus Mandrillus possess a glandular patch of skin (surrounded by bristly hairs) used in olfactory communication on their chests which is more pronounced and developed in dominant adult males (Hill 1970; Feistner 1991; Setchell & Dixson 2001a). In addition, adult male M. sphinx have 4.5 cm (1.8 in) long canines on average, compared to 1.0 cm in females (Leigh et al. 2005; 2008).

M. sphinx
M. sphinx
Photo: Verena Behringer

Overall, body shape and size are similar in the two species of the genus (Grubb 1973). M. leucophaeus on average weigh about 32.3 kg (71.2 lb) (M) and 11.7 kg (25.8 lb) (F) and M. sphinx weigh on average 31.6-33.0 kg (69.7-72.8 lb) (M) and 12.0-12.9 kg (26.5-28.4 lb) (F) (reviewed in Smith & Jungers 1997; Jolly 2007; Marty et al. in press; Joanna Setchell pers. comm.). One M. sphinx female had a head and body length of 56.0 cm (22.0 in), while a M. leucophaeus female had a head and body length of 66.0 cm (26.0 in) (Napier 1981). Adult male mandrills (M. sphinx) weigh over three times what females weigh, indicating marked sexual dimorphism by body weight, the greatest dimorphism among the primates (Setchell et al. 2001; Leigh et al. 2008). M. leucophaeus are also highly sexually dimorphic (Elton & Morgan 2006).

Mandrillus spend a significant of their time on the ground and are predominantly terrestrial, mainly using the forest floor. Even then, they spend more time arboreally than baboons and may feed at all forest levels, including the canopy (Hoshino et al. 1984; Harrison 1988; Gonzalez-Kirchner & de la Maza 1996; Ankel-Simons 2007; Leigh et al. 2008). Time spent in trees however, is usually in levels nearer to the ground (Sabater Pí 1972). Terrestrially, they move through digitigrade quadrupedalism, and terrestrial and arboreal progressions are usually slow (Sabater Pí 1972; Ankel-Simons 2007). Other forms of arboreal locomotion are lateral jumps (Sabater Pí 1972).

In captivity, members of the genus Mandrillus have lived into their late thirties to forty years old (Weigl 2005). Under semi-free-ranging conditions at the Centre International de Recherce Médicales, Franceville (CIRMF), Gabon, males usually live for around 14 years, while females live at least 25 years (Setchell et al. 2005).

RANGE

CURRENT RANGE MAPS (IUCN REDLIST):
Mandrillus leucophaeus | Mandrillus sphinx

The ranges of M. sphinx and M. leucophaeus are incompletely known, but span the region between southern Congo and eastern Nigeria, separated by the Sanaga River in Cameroon, with M. leucophaeus north of this barrier and M. sphinx south of it (Harrison 1988).

M. leucophaeus is found in Cameroon, Nigeria, and Equatorial Guinea. However, its distribution in Equatorial Guinea is limited to Bioko Island, located in the Gulf of Guinea. The range is discontinuous, with the range on the mainland divided into a minimum of 11 areas, and the Bioko Island populations divided into at least two populations, occupying most of the southern part of the island (Gonzalez-Kirchner & de la Maza 1996; Gadsby & Jenkins 1997-1998; Oates & Butynski 2008a). They are present in the west and southwest of Cameroon (as far south as the Sanaga River) as well as limited to southeastern Nigeria (as far west as the Cross River) (Oates & Butynski 2008a). Their distribution in the interior is limited by savannah (Harrison 1988). M. leucophaeus might occur in Gabon, but evidence is unclear and is likely erroneous (Harrison 1988; Blom et al. 1992).

M. sphinx occur just south of the M. leucophaeus distribution, in Cameroon, Republic of Congo (not DRC), mainland Equatorial Guinea, and Gabon (Oates & Butynski 2008b). As one moves south from the Sanaga River, M. sphinx range in Equatorial Guinea, Gabon, and the Republic of Congo as far south as the Congo River, but not east of it (Oates & Butynski 2008b). In the east, M. sphinx are limited in Gabon by the Ivindo and Ogooue Rivers, in Cameroon by the Dja River, and in the southeast of their distribution by savannah (Oates & Butynski 2008b).

HABITAT

M. sphinx inhabits mainly tropical rain forests (including semi-deciduous lowland rainforest, closed-canopy lowland moist forest, and other primary and secondary rainforests often with very dense vegetation) and forest-savannah mosaic forests (never moving far into pure savannah), but also Marantaceae and rocky forest, as well as gallery forest within savannah areas, riparian forests, agricultural areas and even inundated forests and stream beds (Sabater Pí 1972; Hoshino et al. 1984; Hoshino 1985; Lahm 1986; Harrison 1988; Rogers et al. 1996; Tutin et al. 1997a; Matthews et al. 1998; Abernethy et al. 2002; Astaras et al. 2008). They sometimes also cross grassy areas within their forested habitats (Harrison 1988). M. leucophaeus are found in coastal forest, lowland forest, premontane forest, submontane forest, montane forest, and montane savannah, and as high as 2000 meters (6561.7 feet) above sea level (Wild et al. 2005; Astaras et al. 2008).

At the Lopé Reserve, Gabon, a habitat of M. sphinx, there are two dry seasons (one between December and February and one between June and September) with a total annual rainfall of 150.9 cm (59.4 in) (Abernethy et al. 2002). Temperatures are relatively constant year-round, usually ranging between 20 and 33°C (68 and 91.4°F) (Abernethy et al. 2002). At the Korup National Park (KNP), Cameroon, a habitat of M. leucophaeus, average rainfall is over 500 cm (196.9 in), with a wet season between May and October and a dry season between December and February. Similar to the Lopé Reserve, temperatures are relatively constant throughout the year, with average highs around 30.6°C (87.1°F) (Astaras et al. 2008).

In many ways, the often dense habitats of the genus Mandrillus have made research difficult, and as a result, little is known about certain aspects of their ecology and behavior (Hoshino et al. 1984; Jolly 2007).

ECOLOGY

M. sphinx
M. sphinx
Photo: Joanna Setchell

M. leucophaeus and M. sphinx have similar omnivorous diets (Rogers et al. 1996; Astaras et al. 2008). Mainland M. leucophaeus have been seen to consume seeds, fruits, insects, green leaves, and mushrooms, while Bioko Island M. leucophaeus eat fruits (58%), insects (25%) other vegetation including leaves, stems marrows (16%), and other invertebrates such as snails (1%) (Gonzalez-Kirchner & de la Maza 1996; Astaras et al. 2008). M. sphinx consume mostly plant matter, including predominantly fruit, but also leaves, lianas, bark, stems, fibers, animal foods, mushrooms, soils and other foods (Jouventin 1975; Hoshino 1985; Lahm 1986; Rogers et al. 1996). Over one hundred species of plant are consumed in all. Animal foods include predominantly invertebrates (ants, beetles, termites, crickets, spiders, snails and scorpions), as well as birds and eggs and the occasional vertebrate (including tortoises, frogs, porcupines, rats and shrews) (Hoshino 1985; Lahm 1986). For example, Lopé Reserve, Gabon, M. sphinx ate fruit (50.7%), seeds (26.0%), leaves (8.2%), pith (6.8%), flowers (2.7%), animal foods (4.1%) and other foods (1.4%) (Tutin et al. 1997a). There is evidence of probable M. sphinx predation on larger animals as well, including a juvenile bay duiker (Cephalophus dorsalis), a small antelope (Kudo & Mitani 1985).

There is some seasonal variation in the diet of M. sphinx. In Cameroon, fruit is the predominant food for the entire year, but between April and July is less available, and the proportions of other foods (such as leaves) in the diet increases (Hoshino 1985).

M. sphinx spend the night in trees, each night sleeping at a different site (Hoshino 1985). The species is diurnal, with activity starting in the morning, and lasting until the evening, when suitable sleeping trees are found and ascended (Jouventin 1975). In captivity, M. sphinx spend their days feeding (66%), moving (7%), stationary (12%) and in social activities (6%) (Chang et al. 1999).

Ranging information is limited and based on few observations. No annual data is available about ranging, but estimated daily paths of M. sphinx include 2.5-15.0 kilometers (1.6-9.3 miles) per day (one all-day follow at 8 kilometers (5.0 miles)) and estimates of home ranges are between 5 km² (1.9 mi²) and a very large 28 km² (10.8 mi²) (very rough estimates put the value as high as 50 km²(19.3 mi²)) (Jouventin 1975; Hoshino et al. 1984; Hoshino 1985; reviewed in Harrison 1988). To illustrate how variable and incomplete knowledge of ranging is, one horde (more than 600 individuals) of M. sphinx moved only 150 m (492.1 ft) on a single day, while on another it moved 3 km (1.9 mi) (Rogers et al. 1996). The home range of M. leucophaeus is unknown (Astaras et al. 2008).

M. sphinx can be sympatric with a number of other non-human primates. For example, in Gabon, they are sympatric with a number of guenons (Cercopithecus spp.), talapoins (Miopithecus talopoin), mangabeys (Cercocebus spp.), colobus monkeys (Colobus satanas), as well as apes (Pan troglodytes & Gorilla gorilla) (Harrison 1988; Tutin et al. 1997a).

Leopards (Panthera pardus) are known predators of M. sphinx and crowned eagles (Stephanoaetus coronatus) and various snakes probably also take the species (Jouventin 1975; Harrison 1988; Henschel et al. 2005).

Content last modified: October 14, 2009

Written by Kurt Gron. Reviewed by Joanna Setchell.

Cite this page as:
Gron KJ. 2009 October 14. Primate Factsheets: Drill (Mandrillus) Taxonomy, Morphology, & Ecology . <http://pin.primate.wisc.edu/factsheets/entry/drill/taxon>. Accessed 2014 October 25.