The drill (Mandrillus leucophaeus) is one of Africa’s most endangered mammals. It is related to baboons and even more closely to mandrills.
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DiurnalDiurnal animals are active during the daytime, with a period of sleeping or other inactivity at night. The timing of activity by an animal depends ...
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OmnivoreAn omnivore is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and ani...
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. Approx...
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ArborealArboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some anima...
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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AltricialAltricial animals are those species whose newly hatched or born young are relatively immobile. They lack hair or down, are not able to obtain food ...
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ZoochoryZoochory animals are those that can disperse plant seeds in several ways. Seeds can be transported on the outside of vertebrate animals (mostly mam...
Among animals, viviparity is the development of the embryo inside the body of the parent. The term 'viviparity' and its adjective form 'viviparous'...
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Dominance hierarchyA dominance hierarchy (formerly and colloquially called a pecking order) is a type of social hierarchy that arises when members of animal social gr...
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Not a migrantAnimals that do not make seasonal movements and stay in their native home ranges all year round are called not migrants or residents.
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starts withThe drill is a large baboon with a short tail and a dark grey-brown body. This animal is among the most endangered primates in Africa. Drills exhibit well-defined sexual dimorphism with males, being up to twice as large as females. These forest baboons have pink, mauve, and blue rumps. Adult males are distinguished by pink lower lip as well as a dark grey to black face with a white chin and raised grooves on the nose. Meanwhile, females are identified by lacking the pink chin.
The natural range of this species is restricted to Cameroon, where these animals occur north of the Sanaga river and on the south-western edge of the coastal island of Fernando Poo (Bioko). The Korup National Park in the north of Cameroon holds the largest protected population of drills. The preferred habitat of these primates is mature lowland, coastal and riverine forest. However, they are also known to frequent young secondary forests of their range. They generally look for sheltered areas and avoid open terrains.
Drills are diurnal and social animals. They typically form small groups of an average of 20 individuals. These troops consist of one dominant male and multiple related females with their young. During periods of abundant food, drills occasionally occur in large concentrations or super-groups of more than 100 animals. They are semi-terrestrial creatures, sleeping in the lower canopy of the trees. When moving along the ground, they use of all their four limbs. Drills are highly territorial animals. In order to mark their territory, these primates rub their chests on trees. Living in dense forest habitat, drills mainly rely on vocalization to keep contact between members of a troop. The most commonly used vocalizations are two grunting calls.
As omnivorous animals, drills feed upon a wide variety of food, particularly favoring fruits, leaves as well as invertebrates, generally termites. They supplement this diet by raiding manioc and palm oil plantations.
There is no information on reproductive system of this species, although the defined sexual dimorphism suggests that drills may be polygynous with each male having numerous partners. Gestation period lasts for about 179-182 days and young are born in December-April. During the breeding season, each female yields a single baby. The newborn drill remains close to its mother until reaching 15-16 weeks old, when it's completely weaned. Then, males will leave to find another group, whereas females will continue living with their natal group. The age of reproductive maturity is 3 years old in females and 6 years old in males.
During the last 20 years, these primates have largely suffered from destruction of their mature forest habitat, which has led to notable population decline of the drills in Cameroon. On the other, reforestation of the area is mainly associated to planting of exotic, non-palatable species. The drills also attract hunters for their meat, which occasionally come across large concentrations of this species, killing up to 20 animals in a single expedition.
The IUCN Red List doesn’t provide the exact number of the drills’ total population. However, population on the Bioko Island is estimated to remain under 5,000 individuals. Overall, drills are currently classified as Endangered (EN) on the IUCN Red List.
The drills may play some role in seed dispersal, due to their diet. They may also affect predator populations, as items of prey.
Social animals are those animals that interact highly with other animals, usually of their own species (conspecifics), to the point of having a rec...