Mandrill

Last updated

Mandrill [1]
Temporal range: 1.2–0  Ma
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Early Pleistocene – Recent
Mandrill at SF Zoo.jpg
Male mandrill at the San Francisco Zoo
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Suborder: Haplorhini
Infraorder: Simiiformes
Family: Cercopithecidae
Genus: Mandrillus
Species:
M. sphinx
Binomial name
Mandrillus sphinx
Mandrill area.png
Mandrill range
Synonyms

Simia sphinxLinnaeus, 1758

The mandrill (Mandrillus sphinx) is a primate of the Old World monkey (Cercopithecidae) family. [4] It is one of two species assigned to the genus Mandrillus, along with the drill. Both the mandrill and the drill were once classified as baboons in the genus Papio , but they now have their own genus, Mandrillus . [4] Although they look superficially like baboons, they are more closely related to Cercocebus mangabeys. Mandrills are found in southern Cameroon, Gabon, Equatorial Guinea, and Congo. Mandrills mostly live in tropical rainforest and in very large groups. Mandrills have an omnivorous diet consisting mostly of fruits and insects. Their mating season peaks in July to September, with a corresponding birth peak in December to April.

Contents

Mandrills are the world's largest monkeys. The mandrill is classified as vulnerable by IUCN.

Description

The mandrill has an olive green or dark grey pelage with yellow and black bands and a white belly. Its hairless face has an elongated muzzle with distinctive characteristics, such as a red stripe down the middle and protruding blue ridges on the sides. It also has red nostrils and lips, a yellow beard and white tufts. The areas around the genitals and the anus are multi-colored, being red, pink, blue, scarlet, and purple. [5] They also have pale pink ischial callosities. [5] The coloration of the animal is more pronounced in dominant adult males. Both sexes have chest glands, which are used in olfactory communication. These, too, are more prominent in dominant adult males. [6] Males also have longer canines than females, which can be up to 6.35 cm (2.50 in) and 1.0 cm, respectively. [7]

A skeleton of mandrill Mandrillus sphinx skeleton.jpg
A skeleton of mandrill

The mandrill is one of the most sexually dimorphic mammals [8] due to extremely strong sexual selection which favors males in both size and coloration. Males typically weigh 19–37 kg (42–82 lb), with an average mass of 32.3 kg (71 lb). Females weigh roughly half as much as the male, at 10–15 kg (22–33 lb) and an average of 12.4 kg (27 lb). [9] Exceptionally large males can weigh up to 54 kg (119 lb), with unconfirmed reports of outsized mandrills weighing 60 kg (130 lb) per the Guinness Book of World Records. [10] [11] [12] [13] The mandrill is the heaviest living monkey, somewhat surpassing even the largest baboons such as chacma baboon and olive baboons in average weight even considering its more extreme sexual dimorphism, but the mandrill averages both shorter in the length and height at the shoulder than these species. [14] [11] The average male is 75–95 cm (30–37 in) long and the female is 55–66 cm (22–26 in), with the short tail adding another 5–10 cm (2–4 in). [15] [16] The shoulder height while on all fours can range from 45–50 cm (18–20 in) in females and 55–65 cm (22–26 in) in males. Compared to the largest baboons, the mandrill is more ape-like in structure, with a muscular and compact build, shorter, thicker limbs that are longer in the front and almost no tail. [17] [18] [19] Mandrills can live up to 31 years in captivity. Females reach sexual maturity at about 3.5 years.

Coloration

Close-up of a male mandrill's colorful face Mandril.jpg
Close-up of a male mandrill's colorful face

Mandrills are noted as being exceptionally colorful by mammalian standards. Charles Darwin wrote in The Descent of Man : "no other member in the whole class of mammals is colored in so extraordinary a manner as the adult male mandrill's". [20] The bright colors of mandrills are produced by structural coloration in facial collagen fibers; no mammal has blue pigment. [21] [22]

Ecology and activities

The mandrill is found primarily in southern Cameroon, Equatorial Guinea, Congo, and Gabon. Their range may also include Nigeria. Its distribution is bounded by the Sanaga River to the north and the Ogooué and White Rivers to the east. Recent research suggests that mandrill populations north and south of the Ogooué river are so genetically different as to be separate subspecies. Mandrills live in tropical rainforests. They also live in gallery forests adjacent to savannas, as well as rocky forests, riparian forests, cultivated areas and flooded forests and stream beds. [23] [24] Mandrills will cross grass areas within their forest habitats. [25] [26]

Mandrill eating a flower Mandrill and flower.jpg
Mandrill eating a flower

The mandrill is an omnivore. It usually consumes plants, of which it eats over a hundred species. It prefers to eat fruits, but will also eat leaves, lianas, bark, stems, and fibers. It also consumes mushrooms and soil. [24] Carnivorously, mandrills mostly eat invertebrates, particularly ants, beetles, termites, crickets, spiders, snails, and scorpions. It will also eat eggs, and even vertebrates such as birds, tortoises, frogs, porcupines, rats, and shrews. [24] Mandrills likely will eat larger vertebrates when they have the opportunity, such as juvenile bay duikers and other small antelope. Large prey are likely killed with a bite to the nape with the mandrill's long canines. [27] One study found the mandrill's diet was composed of fruit (50.7%), seeds (26.0%), leaves (8.2%), pith (6.8%), flowers (2.7%), and animal foods (4.1%), with other foods making up the remaining (1.4%). [28]

Mandrills are preyed on mainly by leopards. [29] [30] Additional predators known to attack both adult and young mandrills include crowned eagles and African rock pythons. [25] They may be bitten and killed by Boomslangs when they accidentally rouse the venomous snake. It is thought that most predators are a threat mainly to young mandrills, with the likelihood of predation decreasing in adult females and especially adult males, which may be invulnerable to all but the rare ambush by a leopard. In a study where a mandrill troop was exposed to stimuli relating to their natural predators, only the leopard caused the larger part of the group to flee into trees. However, the large, dominant males were observed to remain in response to the images of the natural predators, even the leopard, and pace back and forth while baring their teeth, generally indicating aggression and the defensive role they may play in such circumstances. [29] [30] [31] [32] [33]

Mandrills are mostly terrestrial but they are more arboreal than baboons and feed as high as the canopy. [5] [7] When on the ground, mandrills walk by digitigrade quadrupedalism (walking on the toes of all four limbs). When in the trees, they often move by lateral jumps. [23] Mandrills are mostly diurnal, with activities extending from morning to evening. [34] They sleep in trees at a different site each night. [24] Mandrills have been observed using tools; in captivity, mandrills have been observed using sticks to clean themselves. [35]

Social behavior and reproduction

Mandrill trekking in forest Medium mandrille.jpg
Mandrill trekking in forest

Mandrills seem to live in very large, stable groups named 'hordes'. A horde can number in the hundreds of mandrills, possibly averaging around 615 individuals and reaching as many as 845. [23] [25] [26] It is difficult to accurately estimate horde size in the forest, but filming a horde crossing a gap between two forest patches or crossing a road is a reliable way of estimating the total number. The largest horde verifiably observed in this way contained over 1,300 individuals, in Lopé National Park, Gabon—the largest aggregation of nonhuman primates ever recorded. [36] In the wild, males disperse and only female mandrills remain in their birth group. This benefits females to establish strong relationships with their relatives which can provide support during conflicts, better offspring and longer lifespan. [37] [38] These hordes are made of adult females and their dependent offspring. [39] Males live a solitary lifestyle, and enter hordes only when females are receptive to mating, which lasts three months each year. [25] [39] All-male bachelor groups are not known to exist. [25] [39] The mating season of the mandrill takes place from June to October, which is when the sexual swellings of the female occur. [39] They breed every two years. When breeding, a male will follow and guard a female in estrus. Adult males exist in two different forms: the brightly colored and "fatted" dominant males, and the paler and "nonfatted" subordinate males. Both males engage in mating, but only the dominant males can sire offspring. Males sometimes fight for breeding rights which results in dominance. Though conflicts are rare, they can be deadly. Gaining dominance, that is becoming the alpha male, results in an "increased testicular volume, reddening of sexual skin on the face and genitalia, and heightened secretion of the sternal cutaneous gland". [9] When a male loses dominance or its alpha status, the reverse happens, although the blue ridges remain brightened. There is also a fall in its reproductive success. This effect is gradual and takes place over a few years. [40] [41] [42] When subordinates mate-guard a female, the competition between them allows the dominant males to have a greater chance of siring offspring, [43] since subordinates outnumber dominants 21 to 1. There is also a dominance hierarchy among females, with reproductive success being displayed in shorter interbirth intervals amongst these alpha figures and the beginning of reproduction at earlier ages. [43]

Sleeping mother with young in Hagenbecks Tierpark, Hamburg, Germany Mandrillus sphinx 1.JPG
Sleeping mother with young in Hagenbecks Tierpark, Hamburg, Germany

Mandrill births occur from January to May. [44] Most births in Gabon occur in the wet season, from January to March, and gestation usually lasts 175 days. [43] In captivity, 405 days separate each birth. [43] Young are born with a black natal coat and pink skin. The females do most of the raising of the young. Alloparenting exists in this species, with female relatives providing care for the young. [45] Males leave their natal groups when they are six years old and stay along the boundary of the social group. [25] [39]

Mandrills will make a "silent, bared-teeth face", in which the teeth are bared, the head crest is erect and the head shakes. This may serve as a peaceful form of communication. [46] [47] A mandrill submits by presenting its rump. With aggression, mandrills will stare, bob their heads, and slap the ground. [47] Vocalizations like roars, crowings, and "two-phase grunts" are made for long distances, while "yaks", grunts, "k-alarms", "k-sounds", screams, girneys, and grinds are made at short distances. [48]

Status and conservation

The mandrill is considered vulnerable and is affected by deforestation. [2] However, hunting for bushmeat is the more direct threat. Mandrills are particularly threatened in the Republic of the Congo. [2] Some captive-bred individuals have been successfully reintroduced into the wild. [49]

See also

Related Research Articles

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The chimpanzee, also known as the common chimpanzee, or simply chimp, is a species of great ape native to the forest and savannah of tropical Africa. It has four confirmed subspecies and a fifth proposed subspecies. The chimpanzee and the closely related bonobo are classified in the genus Pan. Evidence from fossils and DNA sequencing shows that Pan is a sister taxon to the human lineage and is humans' closest living relative.

Primatology

Primatology is the scientific study of primates. It is a diverse discipline at the boundary between mammalogy and anthropology, and researchers can be found in academic departments of anatomy, anthropology, biology, medicine, psychology, veterinary sciences and zoology, as well as in animal sanctuaries, biomedical research facilities, museums and zoos. Primatologists study both living and extinct primates in their natural habitats and in laboratories by conducting field studies and experiments in order to understand aspects of their evolution and behaviour.

Old World monkey Family of mammals

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 and macaques. Common names for other Old World monkeys include the talapoin, guenon, colobus, douc, vervet, gelada, mangabey, langur, mandrill, surili (Presbytis), patas, and proboscis monkey. Phylogenetically, they are more closely related to apes than to New World monkeys. They diverged from a common ancestor of New World monkeys around 45 to 55 million years ago.

<i>Mandrillus</i> Genus of Old World monkeys

Mandrillus is a genus of large Old World monkeys distributed throughout central and southern Africa, consisting of two species: M. sphinx and M. leucophaeus, the mandrill and drill, respectively. Mandrillus, originally placed under the genus Papio as a type of baboon, is closely related to the genus Cercocebus. They are characterised by their large builds, elongated snouts with furrows on each side, and stub tails. Both species occupy the west central region of Africa and live primarily on the ground. They are frugivores, consuming both meat and plants, with a preference for plants. M. sphinx is classified as vulnerable and M. leucophaeus as endangered on the IUCN Red List of Threatened Species.

Gelada Species of Old World monkey

The gelada, sometimes called the bleeding-heart monkey or the gelada "baboon", is a species of Old World monkey found only in the Ethiopian Highlands, with large populations in the Simien Mountains. Geladas are actually not baboons but the only living members of the genus Theropithecus. Theropithecus is derived from the Greek root words for "beast-ape". Like its close relatives the baboons, it is largely terrestrial, spending much of its time foraging in grasslands.

Olive baboon Also called the Anubis baboon, is a member of the family Cercopithecidae (Old World monkeys)

The olive baboon, also called the Anubis baboon, is a member of the family Cercopithecidae. The species is the most wide-ranging of all baboons, being found in 25 countries throughout Africa, extending from Mali eastward to Ethiopia and Tanzania. Isolated populations are also present in some mountainous regions of the Sahara. It inhabits savannahs, steppes, and forests. The common name is derived from its coat colour, which is a shade of green-grey at a distance. A variety of communications, vocal and non-vocal, facilitate a complex social structure.

Dominance hierarchy Type of social hierarchy

A dominance hierarchy, formerly and colloquially called a pecking order, is a type of social hierarchy that arises when members of animal social groups interact, creating a ranking system. In social living groups, members are likely to compete for access to limited resources and mating opportunities. Rather than fighting each time they meet, relative rank is established between members of the same sex. Based on repetitive interactions, a social order is created that is subject to change each time a dominant animal is challenged by a subordinate one. In mammals, a dominant individual is sometimes called an alpha.

Hamadryas baboon Species of baboon

The hamadryas baboon is a species of baboon from the Old World monkey family. It is the northernmost of all the baboons, being native to the Horn of Africa and the southwestern tip of the Arabian Peninsula. These regions provide habitats with the advantage for this species of fewer natural predators than central or southern Africa where other baboons reside. The hamadryas baboon was a sacred animal to the ancient Egyptians and appears in various roles in ancient Egyptian religion, hence its alternative name of 'sacred baboon'.

Chacma baboon Species of baboon from the Old World monkey family

The chacma baboon, also known as the Cape baboon, is, like all other baboons, from the Old World monkey family. It is one of the largest of all monkeys. Located primarily in southern Africa, the chacma baboon has a wide variety of social behaviors, including a dominance hierarchy, collective foraging, adoption of young by females, and friendship pairings. These behaviors form parts of a complex evolutionary ecology. In general, the species is not threatened, but human population pressure has increased contact between humans and baboons. Hunting, trapping, and accidents kill or remove many baboons from the wild, thereby reducing baboon numbers and disrupting their social structure.

Harem (zoology)

A harem is an animal group consisting of one or two males, a number of females, and their offspring. The dominant male drives off other males and maintains the unity of the group. If present, the second male is subservient to the dominant male. As juvenile males grow, they leave the group and roam as solitary individuals or join bachelor herds. Females in the group may be inter-related. The dominant male mates with the females as they become sexually active and drives off competitors, until he is displaced by another male. In some species, incoming males that achieve dominant status may commit infanticide.

Sooty mangabey Species of mammal

The sooty mangabey is an Old World monkey found in forests from Senegal in a margin along the coast down to the Ivory Coast.

Kinda baboon Species of mammal

The Kinda baboon is a species of baboon present in the miombo woodlands of Angola, the Democratic Republic of the Congo, Zambia, and possibly western Tanzania. While the Kinda baboon was once considered to be a subspecies of the yellow baboon, it is distinct enough to merit status as full species under the phylogenetic species concept.

Sexual dimorphism in non-human primates

Sexual dimorphism describes the morphological, physiological, and behavioral differences between males and females of the same species. Most primates are sexually dimorphic for different biological characteristics, such as body size, canine tooth size, craniofacial structure, skeletal dimensions, pelage color and markings, and vocalization. However, such sex differences are primarily limited to the anthropoid primates; most of the strepsirrhine primates and tarsiers are monomorphic.

Baboon Genus of mammals

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 baboon. Each species is native to one of six areas of Africa and the hamadryas baboon is also native to part of the Arabian Peninsula. Baboons are among the largest non-hominoid primates and have existed for at least two million years.

One-male group

One-male groups are a type of social organization where one male interacts with a group of females and their immature offspring. Offspring of both sexes are evicted from the group upon reaching puberty. It can be seen in many species of primates, including the gelada baboon, the patas monkey, savanna baboon, sun-tailed monkey, golden snub-nosed monkey, and the hamadryas baboon. There are costs and benefits for individuals living in one-male groups. As well, individuals within one-male groups can interact with each other just like individuals can interact with those from different one-male groups.

Red dress effect

The red dress effect is a phenomenon in which a woman wearing red clothing, such as a red dress, are perceived to be more sexually appealing than she is when wearing other colours. In primates, a visual indicator of female fertility occurs by way of swelling during the follicular phase and is correlated with increased estrogen levels. It has been asserted that this effect acts subconsciously because participants rarely report that they used color in their attractiveness judgments. However, only one study has tested whether conscious awareness matters, with its findings casting doubt on this earlier speculation.

Sexual swelling

Sexual swellings are enlarged areas of genital and perineal skin occurring in some female primates that vary in size over the course of the menstrual cycle. Thought to be an honest signal of fertility, male primates are attracted to these swellings; preferring, and competing for, females with the largest swellings.

Drill (animal) Species of primate

The drill is a primate of the family Cercopithecidae, related to baboons and even more closely to mandrills.

Primate sociality

Primate sociality is an area of primatology that aims to study the interactions between three main elements of a primate social network: the social organisation, the social structure and the mating system. The intersection of these three structures describe the socially complex behaviours and relationships occurring among adult males and females of a particular species. Cohesion and stability of groups are maintained through a confluence of factors, including: kinship, willingness to cooperate, frequency of agonistic behaviours, or varying intensities of dominance structures.

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