Monkeys worldwide fall into two main categories: Platyrrhini [New World Monkeys] and Catarrhini [Old World Monkeys] As their names imply; New World Monkeys are found in South and Central America, and Old World Monkeys inhabit Africa and parts of South and Southeast Asia. Historically, they were also known to have inhabited parts of Europe.

Platyrrini have flat noses with widely spaced nostrils opening to the side, whereas Catarrhini have thin noses with forward or downward pointing nostrils.

Other distinguishing features between the two include the use of a prehensile tail for grasping and holding on to branches in all New World Monkeys, which are all tree dwellers; and limp tails that have no function other than as a balancing rudder when running along a branch for all Old World Monkeys, which aside from the sub-Saharan forest species are mainly larger, heavier, and ground dwelling.

Along with the Tarsiers; Monkeys and Apes [simians or anthropoids] belong in the primate suborder, Haplorhini. The other primate suborder is the Strepsirrhini, which includes the lemuriform primates. Also belonging in the the Strepsirrhini suborder are the extinct Adapiform primates. Detailed information of both suborders are given in the footnotes of this article

The primate lineage is thought to go back at least 65 mya [million years ago] even though the oldest known primates from the fossil record date to the Late Paleocene of Africa [Altiatlasius]* or the Paleocene-Eocene transition in the northern continents, circa 55 mya [Cantius, Donrussellia, Altanius, and Teilhardina]**. Other studies, including molecular clock studies, have estimated the origin of the primate branch to have been in the mid-Cretaceous period, around 85 mya [million years ago].

During the Eocene, most of the northern continents were dominated by two groups, the adapiforms and the omomyids. The former are considered members of Strepsirrhini, but did not have a toothcomb like modern lemurs; recent analysis has demonstrated that Darwinius masillae fits into this grouping. The latter was closely related to tarsiers, monkeys, and apes. How these two groups relate to extant primates is unclear. Omomyids perished about 30 mya, while adapiforms survived until about 10 mya

The Old World monkeys or Cercopithecidae are a group of primates, falling in the superfamily Cercopithecoidea in the clade [or parvorder] of Catarrhini. They are native to Africa and Asia, inhabiting a range of environments from tropical rain forest to savanna, shrubland and mountainous terrain, and are also known from Europe in the fossil record. However, a (possibly introduced) free-roaming group of monkeys [Macaques aka Barbary Apes] still survives in Gibraltar [Europe] to this day. Old World monkeys include many of the most familiar species of nonhuman primates, such as baboons and macaques.

Old World monkeys are medium to large in size, and range from arboreal forms, such as the colobus monkeys, to fully terrestrial forms, such as the baboons. The smallest is the talapoin, with a head and body 34–37 cm in length, and weighing between 0.7 and 1.3 kilograms, while the largest is the male mandrill (the females of the species being significantly smaller), at around 70 cm in length, and weighing up to 50 kilograms.

The featured image in this entry is of a Mandrill, which is also a Sub-Saharan African monkey. It is an illustration drawn with biro and colour-pencils that I created in 1982.

Which came first, the chicken or the egg? The egg of course, all life starts at the basic cellular level and develops into more complex forms, and my Mandrill drawing came long before this article, which has been researched and written, not only in order to explain and display the illustration of the mandrill, but also because Natural History and Wildlife Studies are amongst the many and varied scientific subjects that fascinate me and absorb my interest.

I have set a slideshow depicting the evolution of the Mandrill drawing from the hand-drawn original through its various additional stages of creation in PhotoStudio whilst embarking upon this project. The slideshow is listed as follows:

Mandrill Original Image
Mandrill Recolour
Recolour plus Eye Detail
Recolour Brightened and Refreshed

The Mandrill illustration and its offshoots are merely artistic renditions of an exploratory nature, rather than exact photographic representations, and I therefore claim a bit of creative leeway in their depiction.

Dave Draper September 2014

The following information is taken from Wikipedia.

The mandrill [Mandrillus sphinx] is a primate of the Old World monkey [Cercopithecidae] family, closely related to the baboons and even more closely to the drill. It is found in southern Cameroon, Gabon, Equatorial Guinea, and Congo. Mandrills mostly live in tropical rainforests and forest-savanna mosaics. They live in groups called hordes. Mandrills have an omnivorous diet consisting mostly of fruits and insects. Their mating season takes place from June to October.

Both the mandrill and the drill were once classified as baboons in genus Papio, but recent research has determined they should be separated into their own genus, Mandrillus. Mandrills are the world’s largest monkeys. Charles Darwin wrote in The Descent of Man that “no other member in the whole class of mammals is coloured in so extraordinary a manner as the adult male mandrills.” The mandrill is classified as vulnerable by the IUCN. [International Union for Conservation of Nature]

Description

The mandrill is the most colorful primate. It 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 tuffs. The areas around the genitals and the anus are multi-colored, being colored red, pink, blue, scarlet, and purple. They also have pale pink ischial callosities. 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. Males also have longer canines than females, with an average of 1.8 inches [4.5 cm and 1.0 cm], respectively.

Ecology and activities

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

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. 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. 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. In males, the canines can measure over 2.4 inches in length [6 cm]. 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%].

Mandrills are preyed upon mainly by leopards, in addition to crowned eagles and African Rock Pythons. They may be bitten and killed by Gaboon vipers 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. 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 whilst baring their teeth, generally indicating aggression and the defensive role they may play in such circumstances.

Mandrills are mostly terrestrial but they are more arboreal than baboons and feed as high as the canopy. 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. Mandrills are mostly diurnal, with activities extending from morning to evening. They sleep in trees at a different site each night. Mandrills have been observed using tools; In the wild and in captivity, mandrills have been observed using sticks to clean themselves

Social behavior and reproduction

Mandrills seem to live in large, stable groups called “hordes”. Hordes often number in the hundreds, possibly averaging around 620 individuals and reaching as many as 845. It is difficult to accurately estimate group size in the forest, but filming a group crossing a gap between two forest patches or crossing a road is a reliable way of estimating group size. The largest group verifiably observed in this way contained over 1,300 individuals, in Lopé National Park, Gabon — the largest aggregation of nonhuman primates ever recorded. These groups are made of adult females and their dependent offspring. Males live a solitary lifestyle, and only enter hordes when females are receptive to mating, which lasts three months each year. All-male bachelor groups are not known to exist.

Compiled and edited by Dave Draper September 2014

VNotes