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Primates are a diverse order of mammals. They are divided into the
strepsirrhine Strepsirrhini or Strepsirhini (; ) is a suborder of primates that includes the lemuriform primates, which consist of the lemurs of Madagascar, galagos ("bushbabies") and pottos from Africa, and the lorises from India and southeast Asia. Colle ...
s, which include the lemurs,
galagos Galagos , also known as bush babies, or ''nagapies'' (meaning "night monkeys" in Afrikaans), are small nocturnal primates native to continental, sub-Sahara Africa, and make up the family Galagidae (also sometimes called Galagonidae). They are ...
, and lorisids, and the haplorhines, which include the
tarsiers Tarsiers ( ) are haplorhine primates of the family Tarsiidae, which is itself the lone extant family within the infraorder Tarsiiformes. Although the group was once more widespread, all of its species living today are found in Maritime Southeast ...
and the simians ( monkeys and
ape Apes (collectively Hominoidea ) are a clade of Old World simians native to sub-Saharan Africa and Southeast Asia (though they were more widespread in Africa, most of Asia, and as well as Europe in prehistory), which together with its sister g ...
s, the latter including
human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
s). Primates arose 85–55 million years ago first from small
terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...
mammals, which adapted to living in the trees of tropical forests: many primate characteristics represent adaptations to life in this challenging environment, including large brains, visual acuity, color vision, a shoulder girdle allowing a large degree of movement in the shoulder joint, and dextrous hands. Primates range in size from
Madame Berthe's mouse lemur Madame Berthe's mouse lemur (''Microcebus berthae'') or Berthe's mouse lemur is the smallest of the mouse lemurs and the smallest primate in the world; the average body length is and seasonal weight is around . ''Microcebus berthae'' is one of ...
, which weighs , to the eastern gorilla, weighing over . There are 376–524
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of living primates, depending on which classification is used. New primate species continue to be discovered: over 25 species were described in the 2000s, 36 in the 2010s, and three in the 2020s. Primates have large brains (relative to body size) compared to other mammals, as well as an increased reliance on visual acuity at the expense of the sense of smell, which is the dominant sensory system in most mammals. These features are more developed in monkeys and apes, and noticeably less so in lorises and lemurs. Most primates also have opposable thumbs. Some primates, including gorillas, humans, and baboons, are primarily
terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...
rather than
arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. The habitats pose nu ...
, but all species have adaptations for climbing trees. Arboreal
locomotion Locomotion means the act or ability of something to transport or move itself from place to place. Locomotion may refer to: Motion * Motion (physics) * Robot locomotion, of man-made devices By environment * Aquatic locomotion * Flight * Locomo ...
techniques used include leaping from tree to tree and swinging between branches of trees ( brachiation); terrestrial locomotion techniques include walking on two limbs (
bipedal Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning 'two feet' (from Latin ''bis'' 'double' ...
ism) and modified walking on four limbs (
knuckle-walking Knuckle-walking is a form of quadrupedal walking in which the forelimbs hold the fingers in a partially flexed posture that allows body weight to press down on the ground through the knuckles. Gorillas, bonobos, and chimpanzees use this style o ...
). Primates are among the most social of animals, forming pairs or family groups, uni-male harems, and multi-male/multi-female groups. Non-human primates have at least four types of social systems, many defined by the amount of movement by adolescent females between groups. Primates have slower rates of development than other similarly sized mammals, reach maturity later, and have longer lifespans. Primates are also the most intelligent animals and non-human primates are recorded to use tools. They may communicate using facial and hand gestures, smells and vocalizations. Close interactions between humans and non-human primates (NHPs) can create opportunities for the transmission of zoonotic diseases, especially virus diseases, including
herpes Herpes simplex is a viral infection caused by the herpes simplex virus. Infections are categorized based on the part of the body infected. Oral herpes involves the face or mouth. It may result in small blisters in groups often called cold ...
, measles, ebola, rabies, and hepatitis. Thousands of non-human primates are used in research around the world because of their psychological and physiological similarity to humans. About 60% of primate species are threatened with extinction. Common threats include
deforestation Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated ...
,
forest fragmentation Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processe ...
, monkey drives, and primate hunting for use in medicines, as pets, and for food. Large-scale tropical forest clearing for agriculture most threatens primates.


Etymology

The English name '' primates'' is derived from
Old French Old French (, , ; Modern French: ) was the language spoken in most of the northern half of France from approximately the 8th to the 14th centuries. Rather than a unified language, Old French was a linkage of Romance dialects, mutually intellig ...
or French , from a noun use of Latin , from ('prime, first rank'). The name was given by
Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...
because he thought this the "highest" order of animals. The relationships among the different groups of primates were not clearly understood until relatively recently, so the commonly used terms are somewhat confused. For example, ''ape'' has been used either as an alternative for ''monkey'' or for any tailless, relatively human-like primate. Sir
Wilfrid Le Gros Clark Sir Wilfrid Edward Le Gros Clark (5 June 1895 – 28 June 1971) was a British anatomist, surgeon, primatologist and palaeoanthropologist, today best remembered for his contribution to the study of human evolution. He was Dr Lee's Professor of ...
was one of the
primatologists 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, vete ...
who developed the idea of trends in primate evolution and the methodology of arranging the living members of an order into an "ascending series" leading to humans. Commonly used names for groups of primates such as ''
prosimian Prosimians are a group of primates that includes all living and extinct strepsirrhines ( lemurs, lorisoids, and adapiforms), as well as the haplorhine tarsiers and their extinct relatives, the omomyiforms, i.e. all primates excluding the si ...
s, monkeys, lesser apes'', and '' great apes'' reflect this methodology. According to our current understanding of the evolutionary history of the primates, several of these groups are paraphyletic, or rather they do not include all the descendants of a common ancestor. In contrast with Clark's methodology, modern classifications typically identify (or name) only those groupings that are monophyletic; that is, such a named group includes ''all'' the descendants of the group's common ancestor. The
cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...
below shows one possible classification sequence of the living primates: groups that use common (traditional) names are shown on the right. All groups with scientific names are clades, or monophyletic groups, and the sequence of scientific classification reflects the evolutionary history of the related lineages. Groups that are traditionally named are shown on the right; they form an "ascending series" (per Clark, see above), and several groups are paraphyletic: * Prosimians contain two monophyletic groups (the suborder Strepsirrhini, or lemurs, lorises and allies, as well as the tarsiers of the suborder Haplorhini); it is a paraphyletic grouping because it excludes the Simiiformes, which also are descendants of the common ancestor Primates. * Monkeys comprise two monophyletic groups, New World monkeys and Old World monkeys, but is paraphyletic because it excludes hominoids, superfamily Hominoidea, also descendants of the common ancestor Simiiformes. * Apes as a whole, and the
great apes The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: '' Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); ''Gorilla'' (the ...
, are paraphyletic if the terms are used such that they exclude humans. Thus, the members of the two sets of groups, and hence names, do not match, which causes problems in relating scientific names to common (usually traditional) names. Consider the superfamily Hominoidea: In terms of the common names on the right, this group consists of apes and humans and there is no single common name for all the members of the group. One remedy is to create a new common name, in this case ''hominoids''. Another possibility is to expand the use of one of the traditional names. For example, in his 2005 book, the
vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...
palaeontologist Benton wrote, "The apes, Hominoidea, today include the gibbons and
orangutan Orangutans are great apes native to the rainforests of Indonesia and Malaysia. They are now found only in parts of Borneo and Sumatra, but during the Pleistocene they ranged throughout Southeast Asia and South China. Classified in the genu ...
... the
gorilla Gorillas are herbivorous, predominantly ground-dwelling great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four or fi ...
and chimpanzee ... and
human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
s"; thereby Benton was using ''apes'' to mean hominoids. In that case, the group heretofore called ''apes'' must now be identified as the non-human apes. , there is no consensus as to whether to accept traditional (that is, common), but paraphyletic, names or to use monophyletic names only; or to use 'new' common names or adaptations of old ones. Both competing approaches can be found in biological sources, often in the same work, and sometimes by the same author. Thus, Benton defines ''apes'' to include humans, then he repeatedly uses ''ape-like'' to mean 'like an ape rather than a human'; and when discussing the reaction of others to a new fossil he writes of "claims that ''
Orrorin ''Orrorin tugenensis'' is a postulated early species of Homininae, estimated at and discovered in 2000. It is not confirmed how ''Orrorin'' is related to modern humans. Its discovery was used to argue against the hypothesis that australopithecin ...
'' ... was an ape rather than a human".


Classification of living primates

A list of the families of the living primates is given below, together with one possible classification into ranks between order and family. Other classifications are also used. For example, an alternative classification of the living Strepsirrhini divides them into two infraorders, Lemuriformes and Lorisiformes. * Order Primates ** Suborder Strepsirrhini: lemurs, galagos and lorisids *** Infraorder
Lemuriformes Lemuriformes is an infraorder of primate that falls under the suborder Strepsirrhini. It includes the lemurs of Madagascar, as well as the galagos and lorisids of Africa and Asia, although a popular alternative taxonomy places the lorisoids i ...
**** Superfamily Lemuroidea ***** Family
Cheirogaleidae The Cheirogaleidae are the family of strepsirrhine primates containing the various dwarf and mouse lemurs. Like all other lemurs, cheirogaleids live exclusively on the island of Madagascar. Characteristics Cheirogaleids are smaller than the ...
: dwarf lemurs and mouse-lemurs (41 species) ***** Family
Daubentoniidae ''Daubentonia'' is the sole genus of the Daubentoniidae, a family of lemuroid primate native to much of Madagascar. The aye-aye ''(Daubentonia madagascariensis)'' is the only extant member. However, a second species known as the giant aye-aye ...
: aye-aye (1 species) ***** Family
Lemuridae Lemuridae is a family of strepsirrhine primates native to Madagascar and the Comoros. They are represented by the Lemuriformes in Madagascar with one of the highest concentration of the lemurs. One of five families commonly known as lemurs. Thes ...
: ring-tailed lemur and allies (21 species) ***** Family Lepilemuridae: sportive lemurs (26 species) ***** Family
Indriidae The Indriidae (sometimes incorrectly spelled Indridae) are a family of strepsirrhine primates. They are medium- to large-sized lemurs, with only four teeth in the toothcomb instead of the usual six. Indriids, like all lemurs, live exclusively on ...
: woolly lemurs and allies (19 species) **** Superfamily
Lorisoidea Lorisoidea is a superfamily of nocturnal primates found throughout Africa and Asia. Members include the galagos and the lorisids. As strepsirrhines, lorisoids are related to the lemurs of Madagascar and are sometimes included in the infraorder L ...
***** Family
Lorisidae Lorisidae (or sometimes Loridae) is a family of strepsirrhine primates. The lorisids are all slim arboreal animals and comprise the lorises, pottos and angwantibos. Lorisids live in tropical, central Africa as well as in south and southeast As ...
: lorisids (16 species) ***** Family
Galagidae Galagos , also known as bush babies, or ''nagapies'' (meaning "night monkeys" in Afrikaans), are small nocturnal primates native to continental, sub-Sahara Africa, and make up the family Galagidae (also sometimes called Galagonidae). They are ...
: galagos (23 species) ** Suborder Haplorhini: tarsiers, monkeys and apes *** Infraorder Tarsiiformes **** Family Tarsiidae: tarsiers (14 species) *** Infraorder
Simiiformes The simians, anthropoids, or higher primates are an infraorder (Simiiformes ) of primates containing all animals traditionally called monkeys and apes. More precisely, they consist of the parvorders New World monkeys (Platyrrhini) and Cata ...
(or Anthropoidea) **** Parvorder Platyrrhini: New World monkeys ***** Family Callitrichidae: marmosets and tamarins (49 species) ***** Family Cebidae: capuchins and squirrel monkeys (29 species) ***** Family Aotidae: night or owl monkeys (douroucoulis) (11 species) ***** Family
Pitheciidae The Pitheciidae () are one of the five families of New World monkeys now recognised. Formerly, they were included in the family Atelidae. The family includes the titis, saki monkeys and uakaris. Most species are native to the Amazon region ...
: titis, sakis and uakaris (56 species) ***** Family Atelidae: howler, spider, woolly spider and woolly monkeys (26 species) **** Parvorder
Catarrhini The parvorder Catarrhini , catarrhine monkeys, Old World anthropoids, or Old World monkeys, consisting of the Cercopithecoidea and apes (Hominoidea). In 1812, Geoffroy grouped those two groups together and established the name Catarrhini, "Old ...
***** Superfamily
Cercopithecoidea 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 ...
****** Family Cercopithecidae: Old World monkeys (165 species) ***** Superfamily
Hominoidea Apes (collectively Hominoidea ) are a clade of Old World simians native to sub-Saharan Africa and Southeast Asia (though they were more widespread in Africa, most of Asia, and as well as Europe in prehistory), which together with its sister g ...
****** Family Hylobatidae: gibbons or "lesser apes" (20 species) ****** Family Hominidae: great apes, including humans (8 species) Order Primates was established by
Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...
in 1758, in the tenth edition of his book '' Systema Naturae'', for the genera ''
Homo ''Homo'' () is the genus that emerged in the (otherwise extinct) genus '' Australopithecus'' that encompasses the extant species ''Homo sapiens'' ( modern humans), plus several extinct species classified as either ancestral to or closely relat ...
'' (humans), '' Simia'' (other apes and monkeys), ''
Lemur Lemurs ( ) (from Latin ''lemures'' – ghosts or spirits) are wet-nosed primates of the superfamily Lemuroidea (), divided into 8 families and consisting of 15 genera and around 100 existing species. They are endemic to the island of Madagas ...
'' (prosimians) and ''
Vespertilio ''Vespertilio'' is a genus of bats in the family Vespertilionidae. The common name for this family is vesper bats, which is a better-known classification than ''Vespertilio''. They are also known as frosted bats. Species within the genus ''Vespe ...
'' (bats). In the first edition of the same book (1735), he had used the name Anthropomorpha for ''Homo'', ''Simia'' and '' Bradypus'' (sloths). In 1839,
Henri Marie Ducrotay de Blainville Henri Marie Ducrotay de Blainville (; 12 September 1777 – 1 May 1850) was a French zoologist and anatomist. Life Blainville was born at Arques, near Dieppe. As a young man he went to Paris to study art, but ultimately devoted himself to natur ...
, following Linnaeus and imitating his nomenclature, established the orders Secundates (including the suborders
Chiroptera Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most bir ...
,
Insectivora The order Insectivora (from Latin ''insectum'' "insect" and ''vorare'' "to eat") is a now-abandoned biological grouping within the class of mammals. Some species have now been moved out, leaving the remaining ones in the order Eulipotyphla, wi ...
and Carnivora), Tertiates (or Glires) and Quaternates (including Gravigrada, Pachydermata and Ruminantia), but these new taxa were not accepted. Before Anderson and Jones introduced the classification of Strepsirrhini and Haplorhini in 1984, (followed by McKenna and Bell's 1997 work ''Classification of Mammals: Above the species level''), Primates was divided into two superfamilies:
Prosimii Prosimians are a group of primates that includes all living and extinct strepsirrhines (lemurs, lorisoids, and adapiforms), as well as the haplorhine tarsiers and their extinct relatives, the omomyiforms, i.e. all primates excluding the simi ...
and Anthropoidea. Prosimii included all of the
prosimian Prosimians are a group of primates that includes all living and extinct strepsirrhines ( lemurs, lorisoids, and adapiforms), as well as the haplorhine tarsiers and their extinct relatives, the omomyiforms, i.e. all primates excluding the si ...
s: Strepsirrhini plus the tarsiers. Anthropoidea contained all of the simians.


Phylogeny and genetics

Order Primates is part of the clade
Euarchontoglires Euarchontoglires (synonymous with Supraprimates) is a clade and a superorder of mammals, the living members of which belong to one of the five following groups: rodents, lagomorphs, treeshrews, colugos, and primates. Evolutionary affinities wi ...
, which is nested within the clade
Eutheria Eutheria (; from Greek , 'good, right' and , 'beast'; ) is the clade consisting of all therian mammals that are more closely related to placentals than to marsupials. Eutherians are distinguished from noneutherians by various phenotypic tra ...
of Class Mammalia. Recent molecular genetic research on primates,
colugo Colugos () are arboreal gliding mammals that are native to Southeast Asia. Their closest evolutionary relatives are primates. There are just two living species of colugos: the Sunda flying lemur (''Galeopterus variegatus'') and the Philippine fly ...
s, and treeshrews has shown that the two species of colugos are more closely related to primates than to treeshrews, even though treeshrews were at one time considered primates. These three orders make up the clade
Euarchonta The Euarchonta are a proposed grandorder of mammals: the order Scandentia (treeshrews), and its sister Primatomorpha mirorder, containing the Dermoptera or colugos and the primates (Plesiadapiformes and descendents). The term "Euarchonta" (mea ...
. The combination of this clade with the clade Glires (composed of Rodentia and
Lagomorpha The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two living families: the Leporidae (hares and rabbits) and the Ochotonidae ( pikas). The name of the order is derived from the Ancient Greek ''lagos'' (λαγ ...
) forms the clade Euarchontoglires. Variously, both Euarchonta and Euarchontoglires are ranked as superorders. Some scientists consider Dermoptera to be a suborder of Primates and use the suborder Euprimates for the "true" primates.


Evolution

The primate lineage is thought to go back at least near the Cretaceous–Paleogene boundary or around 63–74 ( mya). The earliest possible primate/proto-primate may be ''
Purgatorius ''Purgatorius'' is a genus of seven extinct eutherian species typically believed to be the earliest example of a primate or a proto-primate, a primatomorph precursor to the Plesiadapiformes, dating to as old as 66 million years ago. The first rem ...
'', which dates back to Early Paleocene of North America ~66mya. The oldest known primates from the fossil record date to the Late Paleocene of Africa, c.57 mya ('' Altiatlasius'') or the Paleocene-Eocene transition in the northern continents, c. 55 mya ('' Cantius'', '' Donrussellia'', '' Altanius'', ''
Plesiadapis ''Plesiadapis'' is one of the oldest known primate-like mammal genera which existed about 58–55 million years ago in North America and Europe. ''Plesiadapis'' means "near-Adapis", which is a reference to the adapiform primate of the Eocene per ...
'' 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. By modern
cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...
reckoning, the order Primates is monophyletic. The suborder Strepsirrhini, the " wet-nosed" primates, is generally thought to have split off from the primitive primate line about 63 mya, although earlier dates are also supported. The seven strepsirrhine families are the five related
lemur Lemurs ( ) (from Latin ''lemures'' – ghosts or spirits) are wet-nosed primates of the superfamily Lemuroidea (), divided into 8 families and consisting of 15 genera and around 100 existing species. They are endemic to the island of Madagas ...
families and the two remaining families that include the lorisids and the
galago Galagos , also known as bush babies, or ''nagapies'' (meaning "night monkeys" in Afrikaans), are small nocturnal primates native to continental, sub-Sahara Africa, and make up the family Galagidae (also sometimes called Galagonidae). They are ...
s. Older classification schemes wrap Lepilemuridae into
Lemuridae Lemuridae is a family of strepsirrhine primates native to Madagascar and the Comoros. They are represented by the Lemuriformes in Madagascar with one of the highest concentration of the lemurs. One of five families commonly known as lemurs. Thes ...
and
Galagidae Galagos , also known as bush babies, or ''nagapies'' (meaning "night monkeys" in Afrikaans), are small nocturnal primates native to continental, sub-Sahara Africa, and make up the family Galagidae (also sometimes called Galagonidae). They are ...
into
Lorisidae Lorisidae (or sometimes Loridae) is a family of strepsirrhine primates. The lorisids are all slim arboreal animals and comprise the lorises, pottos and angwantibos. Lorisids live in tropical, central Africa as well as in south and southeast As ...
, yielding a four-one family distribution instead of five-two as presented here. During the
Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...
, 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 A toothcomb (also tooth comb or dental comb) is a dental structure found in some mammals, comprising a group of front teeth arranged in a manner that facilitates grooming, similar to a hair comb. The toothcomb occurs in lemuriform primates ( ...
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. According to genetic studies, the lemurs of Madagascar diverged from the lorisoids approximately 75 mya. These studies, as well as chromosomal and molecular evidence, also show that lemurs are more closely related to each other than to other strepsirrhine primates. However, Madagascar split from Africa 160 mya and from India 90 mya. To account for these facts, a founding lemur population of a few individuals is thought to have reached Madagascar from Africa via a single rafting event between 50 and 80 mya. Other colonization options have been suggested, such as multiple colonizations from Africa and India, but none are supported by the genetic and molecular evidence. Until recently, the aye-aye has been difficult to place within Strepsirrhini. Theories had been proposed that its family, Daubentoniidae, was either a lemuriform primate (meaning its ancestors split from the lemur line more recently than lemurs and lorises split) or a sister group to all the other strepsirrhines. In 2008, the aye-aye family was confirmed to be most closely related to the other Malagasy lemurs, likely having descended from the same ancestral population that colonized the island. Suborder Haplorhini, the simple-nosed or "dry-nosed" primates, is composed of two sister clades.
Prosimian Prosimians are a group of primates that includes all living and extinct strepsirrhines ( lemurs, lorisoids, and adapiforms), as well as the haplorhine tarsiers and their extinct relatives, the omomyiforms, i.e. all primates excluding the si ...
tarsiers in the family Tarsiidae (monotypic in its own infraorder Tarsiiformes), represent the most basal division, originating about 58 mya. The earliest known haplorhine skeleton, that of 55 MA old tarsier-like '' Archicebus'', was found in central China, supporting an already suspected Asian origin for the group. The infraorder
Simiiformes The simians, anthropoids, or higher primates are an infraorder (Simiiformes ) of primates containing all animals traditionally called monkeys and apes. More precisely, they consist of the parvorders New World monkeys (Platyrrhini) and Cata ...
(simian primates, consisting of monkeys and apes) emerged about 40 mya, possibly also in Asia; if so, they dispersed across the
Tethys Sea The Tethys Ocean ( el, Τηθύς ''Tēthús''), also called the Tethys Sea or the Neo-Tethys, was a prehistoric ocean that covered most of the Earth during much of the Mesozoic Era and early Cenozoic Era, located between the ancient continents ...
from Asia to Africa soon afterwards. There are two simian clades, both
parvorder Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...
s:
Catarrhini The parvorder Catarrhini , catarrhine monkeys, Old World anthropoids, or Old World monkeys, consisting of the Cercopithecoidea and apes (Hominoidea). In 1812, Geoffroy grouped those two groups together and established the name Catarrhini, "Old ...
, which developed in Africa, consisting of
Old World monkey 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 ...
s, humans and the other apes, and Platyrrhini, which developed in South America, consisting of
New World monkey New World monkeys are the five families of primates that are found in the tropical regions of Mexico, Central and South America: Callitrichidae, Cebidae, Aotidae, Pitheciidae, and Atelidae. The five families are ranked together as the Ceboidea ...
s. A third clade, which included the eosimiids, developed in Asia, but became extinct millions of years ago. As in the case of lemurs, the origin of New World monkeys is unclear. Molecular studies of concatenated nuclear sequences have yielded a widely varying estimated date of divergence between platyrrhines and catarrhines, ranging from 33 to 70 mya, while studies based on mitochondrial sequences produce a narrower range of 35 to 43 mya. The anthropoid primates possibly traversed the Atlantic Ocean from Africa to South America during the
Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...
by
island hopping Leapfrogging, also known as island hopping, was a military strategy employed by the Allies in the Pacific War against the Empire of Japan during World War II. The key idea is to bypass heavily fortified enemy islands instead of trying to captu ...
, facilitated by Atlantic Ocean ridges and a lowered sea level. Alternatively, a single rafting event may explain this transoceanic colonization. Due to
continental drift Continental drift is the hypothesis that the Earth's continents have moved over geologic time relative to each other, thus appearing to have "drifted" across the ocean bed. The idea of continental drift has been subsumed into the science of pl ...
, the Atlantic Ocean was not nearly as wide at the time as it is today. Research suggests that a small primate could have survived 13 days on a raft of vegetation. Given estimated current and wind speeds, this would have provided enough time to make the voyage between the continents. Apes and monkeys spread from Africa into Europe and Asia starting in the
Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
. Soon after, the lorises and tarsiers made the same journey. The first hominin fossils were discovered in northern Africa and date back 5–8 mya. Old World monkeys disappeared from Europe about 1.8 mya. Molecular and fossil studies generally show that modern humans originated in Africa 100,000–200,000 years ago. Although primates are well studied in comparison to other animal groups, several new species have been discovered recently, and genetic tests have revealed previously unrecognised species in known populations. ''Primate Taxonomy'' listed about 350 species of primates in 2001; the author,
Colin Groves Colin Peter Groves (24 June 1942 – 30 November 2017) was a British-Australian biologist and anthropologist. Groves was Professor of Biological Anthropology at the Australian National University in Canberra, Australia. Education Born in Englan ...
, increased that number to 376 for his contribution to the third edition of ''
Mammal Species of the World ''Mammal Species of the World: A Taxonomic and Geographic Reference'' is a standard reference work in mammalogy giving descriptions and bibliographic data for the known species of mammals. It is now in its third edition, published in late 2005, ...
'' (MSW3). However, publications since the taxonomy in MSW3 was compiled in 2003 have pushed the number to 522 species, or 708 including subspecies.


Hybrids

Primate hybrids usually arise in captivity, but there have also been examples in the wild. Hybridization occurs where two species' range overlap to form
hybrid zone A hybrid zone exists where the ranges of two interbreeding species or diverged intraspecific lineages meet and cross-fertilize. Hybrid zones can form ''in situ'' due to the evolution of a new lineage but generally they result from secondary contact ...
s; hybrids may be created by humans when animals are placed in zoos or due to environmental pressures such as predation. Intergeneric hybridizations, hybrids of different genera, have also been found in the wild. Although they belong to genera that have been distinct for several million years, interbreeding still occurs between the
gelada The gelada (''Theropithecus gelada'', am, ጭላዳ, translit=č̣əlada), sometimes called the bleeding-heart monkey or the gelada baboon, is a species of Old World monkey found only in the Ethiopian Highlands, living at elevations of above se ...
and the hamadryas baboon.


Clones

On 24 January 2018, scientists in China reported in the journal ''
Cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...
'' the creation of two crab-eating macaque clones, named '' Zhong Zhong'' and '' Hua Hua'', using the complex DNA transfer method that produced ''Dolly'' the sheep, for the first time.


Anatomy and physiology


Head

The primate skull has a large, domed cranium, which is particularly prominent in anthropoids. The cranium protects the large brain, a distinguishing characteristic of this group. The endocranial volume (the volume within the skull) is three times greater in
human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
s than in the greatest nonhuman primate, reflecting a larger brain size. The mean endocranial volume is 1,201 cubic centimeters in humans, 469 cm3 in
gorilla Gorillas are herbivorous, predominantly ground-dwelling great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four or fi ...
s, 400 cm3 in chimpanzees and 397 cm3 in
orangutan Orangutans are great apes native to the rainforests of Indonesia and Malaysia. They are now found only in parts of Borneo and Sumatra, but during the Pleistocene they ranged throughout Southeast Asia and South China. Classified in the genu ...
s. The primary evolutionary trend of primates has been the elaboration of the brain, in particular the neocortex (a part of the
cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consistin ...
), which is involved with sensory perception, generation of motor commands, spatial reasoning, conscious thought and, in humans,
language Language is a structured system of communication. The structure of a language is its grammar and the free components are its vocabulary. Languages are the primary means by which humans communicate, and may be conveyed through a variety of ...
. While other mammals rely heavily on their
sense of smell The sense of smell, or olfaction, is the special sense through which smells (or odors) are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste. In humans, ...
, the arboreal life of primates has led to a tactile, visually dominant sensory system, a reduction in the olfactory region of the brain and increasingly complex social behavior. Primates have forward-facing eyes on the front of the skull;
binocular vision In biology, binocular vision is a type of vision in which an animal has two eyes capable of facing the same direction to perceive a single three-dimensional image of its surroundings. Binocular vision does not typically refer to vision where an ...
allows accurate distance perception, useful for the brachiating ancestors of all great apes. A
bony ridge The linea aspera ( la, rough line) is a ridge of roughened surface on the posterior surface of the shaft of the femur. It is the site of attachments of muscles and the intermuscular septum. Its margins diverge above and below. The linea aspera ...
above the eye sockets reinforces weaker bones in the face, which are put under strain during chewing.
Strepsirrhines Strepsirrhini or Strepsirhini (; ) is a suborder of primates that includes the lemuriform primates, which consist of the lemurs of Madagascar, galagos ("bushbabies") and pottos from Africa, and the lorises from India and southeast Asia. Colle ...
have a postorbital bar, a bone around the eye socket, to protect their eyes; in contrast, the higher primates, haplorhines, have evolved fully enclosed sockets. Primates show an evolutionary trend towards a reduced snout. Technically, Old World monkeys are distinguished from New World monkeys by the structure of the nose, and from apes by the arrangement of their teeth. In New World monkeys, the nostrils face sideways; in Old World monkeys, they face downwards. Dental pattern in primates vary considerably; although some have lost most of their
incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...
s, all retain at least one lower incisor. In most strepsirrhines, the lower incisors form a
toothcomb A toothcomb (also tooth comb or dental comb) is a dental structure found in some mammals, comprising a group of front teeth arranged in a manner that facilitates grooming, similar to a hair comb. The toothcomb occurs in lemuriform primates ( ...
, which is used in grooming and sometimes foraging. Old World monkeys have eight premolars, compared with 12 in New World monkeys. The Old World species are divided into apes and monkeys depending on the number of cusps on their
molars The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...
: monkeys have four, apes have five - although humans may have four or five. The main hominid molar cusp ( hypocone) evolved in early primate history, while the cusp of the corresponding primitive lower molar (paraconid) was lost. Prosimians are distinguished by their immobilized upper lips, the moist tip of their noses and forward-facing lower front teeth.


Body

Primates generally have five digits on each limb ( pentadactyly), with a characteristic type of keratin
fingernail A nail is a claw-like plate found at the tip of the fingers and toes on most primates. Nails correspond to the claws found in other animals. Fingernails and toenails are made of a tough protective protein called alpha-keratin, which is a polymer ...
on the end of each finger and toe. The bottom sides of the hands and feet have sensitive pads on the
fingertips "Fingertips" is a 1963 hit single recorded live by "Little" Stevie Wonder for Motown's then Tamla label. Overview Written and composed by Wonder's mentors, Clarence Paul and Henry Cosby, "Fingertips" was originally a jazz instrumental recorde ...
. Most have opposable thumbs, a characteristic primate feature most developed in
human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
s, though not limited to this order ( opossums and
koala The koala or, inaccurately, koala bear (''Phascolarctos cinereus''), is an arboreal herbivorous marsupial native to Australia. It is the only extant representative of the family Phascolarctidae and its closest living relatives are the w ...
s, for example, also have them). Thumbs allow some species to use tools. In primates, the combination of opposing thumbs, short fingernails (rather than claws) and long, inward-closing fingers is a
relict A relict is a surviving remnant of a natural phenomenon. Biology A relict (or relic) is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas. Geology and geomorphology In geology, a r ...
of the ancestral practice of gripping branches, and has, in part, allowed some species to develop brachiation (swinging by the arms from tree limb to tree limb) as a significant means of locomotion. Prosimians have clawlike nails on the second toe of each foot, called toilet-claws, which they use for grooming. The primate
collar bone The clavicle, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the righ ...
is a prominent element of the
pectoral girdle The shoulder girdle or pectoral girdle is the set of bones in the appendicular skeleton which connects to the arm on each side. In humans it consists of the clavicle and scapula; in those species with three bones in the shoulder, it consists of ...
; this allows the
shoulder joint The shoulder joint (or glenohumeral joint from Greek ''glene'', eyeball, + -''oid'', 'form of', + Latin ''humerus'', shoulder) is structurally classified as a synovial ball-and-socket joint and functionally as a diarthrosis and multiaxial joint ...
broad mobility. Compared to Old World monkeys, apes have more mobile shoulder joints and arms due to the dorsal position of the scapula, broad ribcages that are flatter front-to-back, a shorter, less mobile spine, and with lower
vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristi ...
e greatly reduced - resulting in tail loss in some species. Prehensile tails are found in the New World atelids, including the howler,
spider Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...
, woolly spider,
woolly monkey The woolly monkeys are the genus ''Lagothrix'' of New World monkeys, usually placed in the family Atelidae. Both species in this genus originate from the rainforests of South America. They have prehensile tails and live in relatively large soc ...
s; and in capuchins. Male primates have a low-hanging penis and testes descended into a scrotum.


Sexual dimorphism

Sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most an ...
is often exhibited in simians, though to a greater degree in Old World species (apes and some monkeys) than New World species. Recent studies involve comparing DNA to examine both the variation in the expression of the dimorphism among primates and the fundamental causes of sexual dimorphism. Primates usually have dimorphism in body mass and canine tooth size along with
pelage Fur is a thick growth of hair that covers the skin of mammals. It consists of a combination of oily guard hair on top and thick underfur beneath. The guard hair keeps moisture from reaching the skin; the underfur acts as an insulating blanket ...
and skin color. The dimorphism can be attributed to and affected by different factors, including
mating system A mating system is a way in which a group is structured in relation to sexual behaviour. The precise meaning depends upon the context. With respect to animals, the term describes which males and females mate under which circumstances. Recognised ...
, size, habitat and diet. Comparative analyses have generated a more complete understanding of the relationship between
sexual selection Sexual selection is a mode of natural selection in which members of one biological sex choose mates of the other sex to mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex ( ...
,
natural selection Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Cha ...
, and mating systems in primates. Studies have shown that dimorphism is the product of changes in both male and female traits. Ontogenetic scaling, where relative extension of a common growth trajectory occurs, may give some insight into the relationship between sexual dimorphism and growth patterns. Some evidence from the fossil record suggests that there was convergent evolution of dimorphism, and some extinct hominids probably had greater dimorphism than any living primate.


Locomotion

Primate species move by brachiation,
bipedalism Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning 'two feet' (from Latin ''bis'' 'double' ...
, leaping, arboreal and terrestrial
quadruped Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuor' ...
alism,
climbing Climbing is the activity of using one's hands, feet, or any other part of the body to ascend a steep topographical object that can range from the world's tallest mountains (e.g. the eight thousanders), to small boulders. Climbing is done ...
,
knuckle-walking Knuckle-walking is a form of quadrupedal walking in which the forelimbs hold the fingers in a partially flexed posture that allows body weight to press down on the ground through the knuckles. Gorillas, bonobos, and chimpanzees use this style o ...
or by a combination of these methods. Several prosimians are primarily vertical clingers and leapers. These include many
bushbabies Galagos , also known as bush babies, or ''nagapies'' (meaning "night monkeys" in Afrikaans), are small nocturnal primates native to continental, sub-Sahara Africa, and make up the family Galagidae (also sometimes called Galagonidae). They are ...
, all indriids (i.e.,
sifaka A sifaka (; ) is a lemur of the genus ''Propithecus'' from the family Indriidae within the order Primates. The name of their family is an onomatopoeia of their characteristic "shi-fak" alarm call. Like all lemurs, they are found only on the isl ...
s, avahis and indris), sportive lemurs, and all tarsiers. Other prosimians are arboreal quadrupeds and climbers. Some are also terrestrial quadrupeds, while some are leapers. Most monkeys are both arboreal and terrestrial quadrupeds and climbers. Gibbons, muriquis and
spider monkey Spider monkeys are New World monkeys belonging to the genus ''Ateles'', part of the subfamily Atelinae, family Atelidae. Like other atelines, they are found in tropical forests of Central and South America, from southern Mexico to Brazil. The ...
s all brachiate extensively, with gibbons sometimes doing so in remarkably acrobatic fashion.
Woolly monkey The woolly monkeys are the genus ''Lagothrix'' of New World monkeys, usually placed in the family Atelidae. Both species in this genus originate from the rainforests of South America. They have prehensile tails and live in relatively large soc ...
s also brachiate at times.
Orangutan Orangutans are great apes native to the rainforests of Indonesia and Malaysia. They are now found only in parts of Borneo and Sumatra, but during the Pleistocene they ranged throughout Southeast Asia and South China. Classified in the genu ...
s use a similar form of locomotion called quadramanous climbing, in which they use their arms and legs to carry their heavy bodies through the trees. Chimpanzees and
gorilla Gorillas are herbivorous, predominantly ground-dwelling great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four or fi ...
s knuckle walk, and can move bipedally for short distances. Although numerous species, such as australopithecines and early hominids, have exhibited fully bipedal locomotion, humans are the only extant species with this trait.


Vision

The
evolution of color vision in primates The evolution of color vision in primates is highly unusual compared to most eutherian mammals. A remote vertebrate ancestor of primates possessed tetrachromacy, but nocturnal, warm-blooded, mammalian ancestors lost two of four cones in the retina ...
is unique among most
eutheria Eutheria (; from Greek , 'good, right' and , 'beast'; ) is the clade consisting of all therian mammals that are more closely related to placentals than to marsupials. Eutherians are distinguished from noneutherians by various phenotypic tra ...
n mammals. While the remote
vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...
ancestors of the primates possessed three color vision (trichromaticism), the nocturnal,
warm-blooded Warm-blooded is an informal term referring to animal species which can maintain a body temperature higher than their environment. In particular, homeothermic species maintain a stable body temperature by regulating metabolic processes. The onl ...
, mammalian ancestors lost one of three cones in the
retina The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...
during the
Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...
era. Fish, reptiles and birds are therefore trichromatic or tetrachromatic, while all mammals, with the exception of some primates and marsupials, are dichromats or monochromats (totally color blind). Nocturnal primates, such as the
night monkey Night monkeys, also known as owl monkeys or douroucoulis (), are nocturnal New World monkeys of the genus ''Aotus'', the only member of the family Aotidae (). The genus comprises eleven species which are found across Panama and much of South Am ...
s and bush babies, are often monochromatic. Catarrhines are routinely trichromatic due to a gene duplication of the red-green opsin gene at the base of their lineage, 30 to 40 million years ago. Platyrrhines, on the other hand, are trichromatic in a few cases only. Specifically, individual females must be heterozygous for two
allele An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chro ...
s of the opsin gene (red and green) located on the same
locus Locus (plural loci) is Latin for "place". It may refer to: Entertainment * Locus (comics), a Marvel Comics mutant villainess, a member of the Mutant Liberation Front * ''Locus'' (magazine), science fiction and fantasy magazine ** ''Locus Award' ...
of the X chromosome. Males, therefore, can only be dichromatic, while females can be either dichromatic or trichromatic. Color vision in strepsirrhines is not as well understood; however, research indicates a range of color vision similar to that found in platyrrhines. Like catarrhines, howler monkeys (a family of platyrrhines) show routine trichromatism that has been traced to an evolutionarily recent gene duplication. Howler monkeys are one of the most specialized leaf-eaters of the New World monkeys; fruits are not a major part of their diets, and the type of leaves they prefer to consume (young, nutritive, and digestible) are detectable only by a red-green signal. Field work exploring the dietary preferences of howler monkeys suggests that routine trichromaticism was selected by environment.


Behavior


Social systems

Richard Wrangham Richard Walter Wrangham (born 1948) is an English anthropologist and primatologist; he is Professor of Biological Anthropology at Harvard University. His research and writing have involved ape behavior, human evolution, violence, and cooking. ...
stated that social systems of primates are best classified by the amount of movement by females occurring between groups. He proposed four categories: * Female transfer systems – females move away from the group in which they were born. Females of a group will not be closely related whereas males will have remained with their natal groups, and this close association may be influential in social behavior. The groups formed are generally quite small. This organization can be seen in chimpanzees, where the males, who are typically related, will cooperate in defense of the group's territory. Evidence of this social system has also been found among Neanderthal remains in
Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...
and in remains of '' Australopithecus'' and '' Paranthropus robustus'' groups in southern Africa. Among New World Monkeys,
spider monkey Spider monkeys are New World monkeys belonging to the genus ''Ateles'', part of the subfamily Atelinae, family Atelidae. Like other atelines, they are found in tropical forests of Central and South America, from southern Mexico to Brazil. The ...
s and muriquis use this system. * Male transfer systems – while the females remain in their natal groups, the males will emigrate as adolescents. Polygynous and multi-male societies are classed in this category. Group sizes are usually larger. This system is common among the ring-tailed lemur,
capuchin monkey The capuchin monkeys () are New World monkeys of the subfamily Cebinae. They are readily identified as the " organ grinder" monkey, and have been used in many movies and television shows. The range of capuchin monkeys includes some tropical fores ...
s and cercopithecine monkeys. * Monogamous species – a male–female bond, sometimes accompanied by a juvenile offspring. There is shared responsibility of parental care and territorial defense. The offspring leaves the parents' territory during adolescence. Gibbons essentially use this system, although "monogamy" in this context does not necessarily mean absolute sexual fidelity. These species do not live in larger groups. * Solitary species – often males who defend territories that include the home ranges of several females. This type of organization is found in the prosimians such as the
slow loris Slow lorises are a group of several species of nocturnal strepsirrhine primates that make up the genus ''Nycticebus''. Found in Southeast Asia and bordering areas, they range from Bangladesh and Northeast India in the west to the Sulu Archip ...
.
Orangutan Orangutans are great apes native to the rainforests of Indonesia and Malaysia. They are now found only in parts of Borneo and Sumatra, but during the Pleistocene they ranged throughout Southeast Asia and South China. Classified in the genu ...
s do not defend their territory but effectively have this organization. Other systems are known to occur as well. For example, with
howler monkey Howler monkeys (genus ''Alouatta'', monotypic in subfamily Alouattinae) are the most widespread primate genus in the Neotropics and are among the largest of the platyrrhines along with the muriquis (''Brachyteles''), the spider monkeys (''Atele ...
s and
gorilla Gorillas are herbivorous, predominantly ground-dwelling great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four or fi ...
s both the males and females typically transfer from their natal group on reaching sexual maturity, resulting in groups in which neither the males nor females are typically related. Some prosimians,
colobine The Colobinae or leaf-eating monkeys are a subfamily of the Old World monkey family that includes 61 species in 11 genera, including the black-and-white colobus, the large-nosed proboscis monkey, and the gray langurs. Some classifications split ...
monkeys and callitrichid monkeys also use this system. The transfer of females or males from their native group is likely an adaptation for avoiding inbreeding. An analysis of breeding records of captive primate colonies representing numerous different species indicates that the infant mortality of inbred young is generally higher than that of non-inbred young. This effect of inbreeding on infant mortality is probably largely a result of increased expression of deleterious recessive alleles (see Inbreeding depression). Primatologist
Jane Goodall Dame Jane Morris Goodall (; born Valerie Jane Morris-Goodall on 3 April 1934), formerly Baroness Jane van Lawick-Goodall, is an English primatologist and anthropologist. Seen as the world's foremost expert on chimpanzees, Goodall is best kn ...
, who studied in the Gombe Stream National Park, noted fission-fusion societies in chimpanzees. There is ''fission'' when the main group splits up to forage during the day, then ''fusion'' when the group returns at night to sleep as a group. This social structure can also be observed in the hamadryas baboon,
spider monkey Spider monkeys are New World monkeys belonging to the genus ''Ateles'', part of the subfamily Atelinae, family Atelidae. Like other atelines, they are found in tropical forests of Central and South America, from southern Mexico to Brazil. The ...
s and the bonobo. The
gelada The gelada (''Theropithecus gelada'', am, ጭላዳ, translit=č̣əlada), sometimes called the bleeding-heart monkey or the gelada baboon, is a species of Old World monkey found only in the Ethiopian Highlands, living at elevations of above se ...
has a similar social structure in which many smaller groups come together to form temporary herds of up to 600 monkeys.
Human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
s also form fission-fusion societies. In hunter-gatherer societies, humans form groups which are made up of several individuals that may split up to obtain different resources. These social systems are affected by three main ecological factors: distribution of resources, group size, and predation. Within a social group there is a balance between cooperation and competition. Cooperative behaviors in many primates species include social grooming (removing skin parasites and cleaning wounds), food sharing, and collective defense against predators or of a territory. Aggressive behaviors often signal competition for food, sleeping sites or mates. Aggression is also used in establishing dominance hierarchies.


Interspecific associations

Several species of primates are known to associate in the wild. Some of these associations have been extensively studied. In the Tai Forest of Africa several species coordinate anti-predator behavior. These include the Diana monkey,
Campbell's mona monkey Campbell's mona monkey (''Cercopithecus campbelli''), also known as Campbell's guenon and Campbell's monkey, is a species of primate in the family Cercopithecidae found in the Ivory Coast, Gambia, Ghana, Guinea, Guinea-Bissau, Liberia, Senegal, a ...
, lesser spot-nosed monkey, western red colobus,
king colobus The king colobus (''Colobus polykomos''), also known as the western black-and-white colobus, is a species of Old World monkey, found in lowland and mountain rainforests in a region stretching from Senegal, through Guinea-Bissau, Guinea, Sierra Le ...
(western black and white colobus), and sooty mangabey, which coordinate anti-predator alarm calls. Among the predators of these monkeys is the common chimpanzee. The red-tailed monkey associates with several species, including the western red colobus,
blue monkey The blue monkey or diademed monkey (''Cercopithecus mitis'') is a species of Old World monkey native to Central and East Africa, ranging from the upper Congo River basin east to the East African Rift and south to northern Angola and Zambia. It ...
,
Wolf's mona monkey Wolf's mona monkey (''Cercopithecus wolfi''), also called Wolf's guenon, is a colourful Old World monkey in the family Cercopithecidae. It is found in central Africa, primarily between the Democratic Republic of the Congo and Uganda. It lives in ...
, mantled guereza, black crested mangabey and Allen's swamp monkey. Several of these species are preyed upon by the common chimpanzee. In South America,
squirrel monkey Squirrel monkeys are New World monkeys of the genus ''Saimiri''. ''Saimiri'' is the only genus in the subfamily Saimirinae. The name of the genus is of Tupi origin (''sai-mirím'' or ''çai-mbirín'', with ''sai'' meaning 'monkey' and ''mirím'' ...
s associate with
capuchin monkey The capuchin monkeys () are New World monkeys of the subfamily Cebinae. They are readily identified as the " organ grinder" monkey, and have been used in many movies and television shows. The range of capuchin monkeys includes some tropical fores ...
s. This may have more to do with foraging benefits to the squirrel monkeys than anti-predation benefits.


Communication

Lemur Lemurs ( ) (from Latin ''lemures'' – ghosts or spirits) are wet-nosed primates of the superfamily Lemuroidea (), divided into 8 families and consisting of 15 genera and around 100 existing species. They are endemic to the island of Madagas ...
s,
loris Loris is the common name for the strepsirrhine mammals of the subfamily Lorinae (sometimes spelled Lorisinae) in the family Lorisidae. ''Loris'' is one genus in this subfamily and includes the slender lorises, ''Nycticebus'' is the genus conta ...
es, tarsiers, and New World monkeys rely on olfactory signals for many aspects of social and reproductive behavior. Specialized glands are used to mark territories with
pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
s, which are detected by the vomeronasal organ; this process forms a large part of the communication behavior of these primates. In Old World monkeys and apes this ability is mostly
vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...
, having regressed as
trichromatic Trichromacy or trichromatism is the possessing of three independent channels for conveying color information, derived from the three different types of cone cells in the eye. Organisms with trichromacy are called trichromats. The normal expl ...
eyes evolved to become the main sensory organ. Primates also use vocalizations, gestures, and facial expressions to convey psychological state. Facial musculature is very developed in primates, particularly in monkeys and apes, allowing for complex facial communication. Like humans, chimpanzees can distinguish the faces of familiar and unfamiliar individuals. Hand and arm gestures are also important forms of communication for great apes and a single gesture can have multiple functions. Primates are a particularly vocal group of mammals. Indris and
black-and-white ruffed lemur The black-and-white ruffed lemur (''Varecia variegata'') is an endangered species of ruffed lemur, one of two which are endemic to the island of Madagascar. Despite having a larger range than the red ruffed lemur, it has a much smaller populati ...
s make distinctive, loud songs and choruses which maintain territories and act as alarm calls. The Philippine tarsier, has a high-frequency limit of auditory sensitivity of approximately 91 kHz with a dominant frequency of 70 kHz, among the highest recorded for any terrestrial mammal. For Philippine tarsiers, these ultrasonic vocalizations might represent a private channel of communication that subverts detection by predators, prey and competitors, enhances energetic efficiency, or improves detection against low-frequency background noise. Male
howler monkey Howler monkeys (genus ''Alouatta'', monotypic in subfamily Alouattinae) are the most widespread primate genus in the Neotropics and are among the largest of the platyrrhines along with the muriquis (''Brachyteles''), the spider monkeys (''Atele ...
s are among the loudest land mammals as their roars can be heard up to , and relate to intergroup spacing, territorial protection and possibly mate-guarding. Roars are produced by modified larynx and enlarged hyoid bone which contains an air sac. The
vervet monkey The vervet monkey (''Chlorocebus pygerythrus''), or simply vervet, is an Old World monkey of the family Cercopithecidae native to Africa. The term "vervet" is also used to refer to all the members of the genus ''Chlorocebus''. The five distinct ...
gives a distinct alarm call for each of at least four different predators, and the reactions of other monkeys vary according to the call. Male and female siamangs both possess inflatable pouches in the throat with which pair -bonds use to sing "duets" to each other. Many non-human primates have the vocal anatomy to produce human speech but lack the proper brain wiring. Vowel-like vocal patterns have been recorded in baboons which has implications for the origin of speech in humans. Consonant- and vowel-like sounds exist in some orangutan calls and they maintain their meaning over great distances. The time range for the evolution of human language and/or its anatomical prerequisites extends, at least in principle, from the phylogenetic divergence of ''
Homo ''Homo'' () is the genus that emerged in the (otherwise extinct) genus '' Australopithecus'' that encompasses the extant species ''Homo sapiens'' ( modern humans), plus several extinct species classified as either ancestral to or closely relat ...
'' (2.3 to 2.4 million years ago) from '' Pan'' (5 to 6 million years ago) to the emergence of full
behavioral modernity Behavioral modernity is a suite of behavioral and cognitive traits that distinguishes current '' Homo sapiens'' from other anatomically modern humans, hominins, and primates. Most scholars agree that modern human behavior can be characterize ...
some 50,000–150,000 years ago. Few dispute that '' Australopithecus'' probably lacked vocal communication significantly more sophisticated than that of great apes in general.


Life history

Primates have slower rates of development than other mammals. All primate infants are
breastfed Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that brea ...
by their mothers (with the exception of some human cultures and various zoo raised primates which are fed formula) and rely on them for grooming and transportation. In some species, infants are protected and transported by males in the group, particularly males who may be their fathers. Other relatives of the infant, such as siblings and aunts, may participate in its care as well. Most primate mothers cease
ovulation Ovulation is the release of eggs from the ovaries. In women, this event occurs when the ovarian follicles rupture and release the secondary oocyte ovarian cells. After ovulation, during the luteal phase, the egg will be available to be fertilize ...
while breastfeeding an infant; once the infant is
weaned Weaning is the process of gradually introducing an infant human or another mammal to what will be its adult diet while withdrawing the supply of its mother's milk. The process takes place only in mammals, as only mammals produce milk. The infan ...
the mother can reproduce again. This often leads to weaning conflict with infants who attempt to continue breastfeeding. Infanticide is common in polygynous species such as
gray langur Gray langurs, also called Hanuman langurs and Hanuman monkeys, are Old World monkeys native to the Indian subcontinent constituting the genus ''Semnopithecus''. Traditionally only one species ''Semnopithecus entellus'' was recognized, but since a ...
s and gorillas. Adult males may kill dependent offspring that are not theirs so the female will return to estrus and thus they can sire offspring of their own. Social monogamy in some species may have evolved to combat this behavior. Promiscuity may also lessen the risk of infanticide since paternity becomes uncertain. Primates have a longer juvenile period between weaning and sexual maturity than other mammals of similar size. Some primates such as
galago Galagos , also known as bush babies, or ''nagapies'' (meaning "night monkeys" in Afrikaans), are small nocturnal primates native to continental, sub-Sahara Africa, and make up the family Galagidae (also sometimes called Galagonidae). They are ...
s and
new world monkey New World monkeys are the five families of primates that are found in the tropical regions of Mexico, Central and South America: Callitrichidae, Cebidae, Aotidae, Pitheciidae, and Atelidae. The five families are ranked together as the Ceboidea ...
s use tree-holes for nesting, and park juveniles in leafy patches while foraging. Other primates follow a strategy of "riding", i.e. carrying individuals on the body while feeding. Adults may construct or use nesting sites, sometimes accompanied by juveniles, for the purpose of resting, a behavior which has developed secondarily in the great apes. During the juvenile period, primates are more susceptible than adults to predation and starvation; they gain experience in feeding and avoiding predators during this time. They learn social and fighting skills, often through playing. Primates, especially females, have longer lifespans than other similarly sized mammals, this may be partially due to their slower metabolisms. Late in life, female catarrhine primates appear to undergo a cessation of reproductive function known as menopause; other groups are less studied.


Diet and feeding

Primates exploit a variety of food sources. It has been said that many characteristics of modern primates, including humans, derive from an early ancestor's practice of taking most of its food from the tropical canopy. Most primates include fruit in their diets to obtain easily digested nutrients including
carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or m ...
s and lipids for energy. Primates in the suborder Strepsirrhini (non-tarsier prosimians) are able to synthesize vitamin C, like most other mammals, while primates of the suborder Haplorhini (tarsiers, monkeys and apes) have lost this ability, and require the vitamin in their diet. Many primates have anatomical specializations that enable them to exploit particular foods, such as fruit, leaves, gum or
insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...
s. For example, leaf eaters such as howler monkeys, black-and-white colobuses and sportive lemurs have extended digestive tracts which enable them to absorb nutrients from leaves that can be difficult to digest. Marmosets, which are gum eaters, have strong
incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...
teeth, enabling them to open tree bark to get to the gum, and claws rather than nails, enabling them to cling to trees while feeding. The aye-aye combines rodent-like teeth with a long, thin middle finger to fill the same ecological niche as a woodpecker. It taps on trees to find insect larvae, then gnaws holes in the wood and inserts its elongated middle finger to pull the larvae out. Some species have additional specializations. For example, the grey-cheeked mangabey has thick enamel on its teeth, enabling it to open hard fruits and seeds that other monkeys cannot. The
gelada The gelada (''Theropithecus gelada'', am, ጭላዳ, translit=č̣əlada), sometimes called the bleeding-heart monkey or the gelada baboon, is a species of Old World monkey found only in the Ethiopian Highlands, living at elevations of above se ...
is the only primate species that feeds primarily on grass.


Hunting

Tarsiers are the only extant obligate carnivorous primates, exclusively eating insects, crustaceans, small vertebrates and snakes (including
venomous Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...
species).
Capuchin monkey The capuchin monkeys () are New World monkeys of the subfamily Cebinae. They are readily identified as the " organ grinder" monkey, and have been used in many movies and television shows. The range of capuchin monkeys includes some tropical fores ...
s can exploit many different types of plant matter, including fruit, leaves, flowers, buds, nectar and seeds, but also eat insects and other invertebrates, bird eggs, and small vertebrates such as birds, lizards, squirrels and
bat Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most ...
s. The common chimpanzee eats an
omnivorous An 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 animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...
frugivorous diet. It prefers fruit above all other food items and even seeks out and eats them when they are not abundant. It also eats leaves and leaf buds, seeds, blossoms, stems, pith, bark and resin. Insects and meat make up a small proportion of their diet, estimated as 2%. The meat consumption includes predation on other primate species, such as the western red colobus monkey. The bonobo is an
omnivorous An 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 animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...
frugivore – the majority of its diet is fruit, but it supplements this with leaves, meat from small
vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...
s, such as
anomalure The Anomaluridae are a family of rodents found in central Africa. They are known as anomalures or scaly-tailed squirrels. The six extant species are classified into two genera. All anomalurids have membranes between their front and hind legs li ...
s, flying squirrels and duikers, and invertebrates. In some instances, bonobos have been shown to consume lower-order primates. Until the development of agriculture approximately 10,000 years ago, ''Homo sapiens'' employed a hunter-gatherer method as their sole means of food collection. This involved combining stationary food sources (such as fruits, grains, tubers, and mushrooms, insect larvae and aquatic mollusks) with
wild game Game or quarry is any wild animal hunted for animal products (primarily meat), for recreation (" sporting"), or for trophies. The species of animals hunted as game varies in different parts of the world and by different local jurisdictions, th ...
, which must be hunted and killed in order to be consumed. It has been proposed that humans have used fire to prepare and cook food since the time of '' Homo erectus''. Around ten thousand years ago, humans developed agriculture, which substantially altered their diet. This change in diet may also have altered human biology; with the spread of dairy farming providing a new and rich source of food, leading to the evolution of the ability to digest lactose in some adults.


As prey

Predators of primates include various species of carnivorans,
birds of prey Birds of prey or predatory birds, also known as raptors, are hypercarnivorous bird species that actively hunt and feed on other vertebrates (mainly mammals, reptiles and other smaller birds). In addition to speed and strength, these predat ...
, reptiles, and other primates. Even gorillas have been recorded as prey. Predators of primates have diverse hunting strategies and as such, primates have evolved several different
antipredator adaptation Anti-predator adaptations are mechanisms developed through evolution that assist prey organisms in their constant struggle against predators. Throughout the animal kingdom, adaptations have evolved for every stage of this struggle, namely by avo ...
s including crypsis,
alarm calls In animal communication, an alarm signal is an antipredator adaptation in the form of Signalling theory, signals emitted by social animals in response to danger. Many primates and birds have elaborate alarm calls for warning Biological specific ...
and
mobbing Mobbing, as a sociological term, means bullying of an individual by a group, in any context, such as a family, peer group, school, workplace, neighborhood, community, or online. When it occurs as physical and emotional abuse in the workplace, suc ...
. Several species have separate alarm calls for different predators such as air-borne or ground-dwelling predators. Predation may have shaped group size in primates as species exposed to higher predation pressures appear to live in larger groups.


Intelligence and cognition

Primates have advanced cognitive abilities: some make tools and use them to acquire food and for social displays; some can perform tasks requiring cooperation, influence and rank; they are status conscious, manipulative and capable of deception; they can recognise
kin __NOTOC__ Kin usually refers to kinship and family. Kin or KIN may also refer to: Culture and religion *Otherkin, people who identify as not entirely human *Kinism, a white supremacist religious movement * Kinh, the majority ethnic group of V ...
and
conspecific Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species. Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organis ...
s; and they can learn to use symbols and understand aspects of human language including some relational syntax and concepts of number and numerical sequence. Research in primate cognition explores problem solving, memory, social interaction, a theory of mind, and numerical, spatial, and abstract concepts. Comparative studies show a trend towards higher intelligence going from prosimians to New World monkeys to Old World monkeys, and significantly higher average cognitive abilities in the great apes. However, there is a great deal of variation in each group (e.g., among New World monkeys, both
spider Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...
and
capuchin monkey The capuchin monkeys () are New World monkeys of the subfamily Cebinae. They are readily identified as the " organ grinder" monkey, and have been used in many movies and television shows. The range of capuchin monkeys includes some tropical fores ...
s have scored highly by some measures), as well as in the results of different studies.


Tool use and manufacture

In 1960,
Jane Goodall Dame Jane Morris Goodall (; born Valerie Jane Morris-Goodall on 3 April 1934), formerly Baroness Jane van Lawick-Goodall, is an English primatologist and anthropologist. Seen as the world's foremost expert on chimpanzees, Goodall is best kn ...
observed a chimpanzee poking pieces of grass into a termite mound and then raising the grass to his mouth. After he left, Goodall approached the mound and repeated the behaviour because she was unsure what the chimpanzee was doing. She found that the termites bit onto the grass with their jaws. The chimpanzee had been using the grass as a tool to "fish" or "dip" for termites. There are more limited reports of the closely related bonobo using tools in the wild; it has been claimed they rarely use tools in the wild although they use tools as readily as chimpanzees when in captivity. It has been reported that females, both chimpanzee and bonobo, use tools more avidly than males.
Orangutan Orangutans are great apes native to the rainforests of Indonesia and Malaysia. They are now found only in parts of Borneo and Sumatra, but during the Pleistocene they ranged throughout Southeast Asia and South China. Classified in the genu ...
s in Borneo scoop catfish out of small ponds. Over two years, anthropologist Anne Russon observed orangutans learning to jab sticks at catfish to scare them out of the ponds and in to their waiting hands. There are few reports of
gorilla Gorillas are herbivorous, predominantly ground-dwelling great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four or fi ...
s using tools in the wild. An adult female western lowland gorilla used a branch as a walking stick apparently to test water depth and to aid her in crossing a pool of water. Another adult female used a detached trunk from a small shrub as a stabilizer during food gathering, and another used a log as a bridge. The first direct observation of a non-ape primate using a tool in a wild environment occurred in 1988. Primatologist Sue Boinski watched an adult male white-faced capuchin beat a fer-de-lance snake to death with a dead branch. The black-striped capuchin was the first non-ape primate for which routine tool use was documented in the wild; individuals were observed cracking nuts by placing them on a stone anvil and hitting them with another large stone. In Thailand and Myanmar, crab-eating macaques use stone tools to open nuts, oysters and other bivalves, and various types of sea snails. Chacma baboons use stones as weapons; stoning by these baboons is done from the rocky walls of the canyon where they sleep and retreat to when they are threatened. Stones are lifted with one hand and dropped over the side whereupon they tumble down the side of the cliff or fall directly to the canyon floor. Although they have not been observed to use tools in the wild, lemurs in controlled settings have been shown to be capable of understanding the functional properties of the objects they had been trained to use as tools, performing as well as tool-using haplorhines. Soon after her initial discovery of tool use, Goodall observed other chimpanzees picking up leafy twigs, stripping off the leaves and using the stems to fish for insects. This change of a leafy twig into a tool was a major discovery. Prior to this, scientists thought that only
human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
s manufactured and used tools, and that this ability was what separated humans from other animals. Chimpanzees have also been observed making "sponges" out of leaves and moss that suck up water. Sumatran orangutans have been observed making and using tools. They will break off a tree branch that is about 30 cm long, snap off the twigs, fray one end and then use the stick to dig in tree holes for termites. In the wild, mandrills have been observed to clean their ears with modified tools. Scientists filmed a large male mandrill at Chester Zoo (UK) stripping down a twig, apparently to make it narrower, and then using the modified stick to scrape dirt from underneath its toenails. Captive gorillas have made a variety of tools.


Ecology

Non-human primates primarily live in the tropical latitudes of Africa, Asia, and the Americas. Species that live outside of the tropics; include the
Japanese macaque The Japanese macaque (''Macaca fuscata''), also known as the snow monkey, is a terrestrial Old World monkey species that is native to Japan. Colloquially, they are referred to as "snow monkeys" because some live in areas where snow covers the gr ...
which lives in the Japanese islands of Honshū and
Hokkaido is Japan's second largest island and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by the undersea railway Seikan Tunnel. The lar ...
; the Barbary macaque which lives in North Africa and several species of langur which live in China. Primates tend to live in
tropical rainforest Tropical rainforests are rainforests that occur in areas of tropical rainforest climate in which there is no dry season – all months have an average precipitation of at least 60 mm – and may also be referred to as ''lowland equa ...
s but are also found in temperate forests, savannas, deserts, mountains and coastal areas. The number of primate species within tropical areas has been shown to be positively correlated to the amount of rainfall and the amount of rain forest area. Accounting for 25% to 40% of the fruit-eating animals (by
weight In science and engineering, the weight of an object is the force acting on the object due to gravity. Some standard textbooks define weight as a vector quantity, the gravitational force acting on the object. Others define weight as a scalar qua ...
) within tropical rainforests, primates play an important
ecological Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps wi ...
role by dispersing seeds of many tree species. Primate habitats span a range of altitudes: the black snub-nosed monkey has been found living in the Hengduan Mountains at altitudes of 4,700 meters (15,400 ft), the mountain gorilla can be found at 4,200 meters (13,200 ft) crossing the Virunga Mountains, and the gelada has been found at elevations of up to in the
Ethiopian Highlands The Ethiopian Highlands is a rugged mass of mountains in Ethiopia in Northeast Africa. It forms the largest continuous area of its elevation in the continent, with little of its surface falling below , while the summits reach heights of up to . ...
. Some species interact with aquatic environments and may swim or even dive, including the proboscis monkey,
De Brazza's monkey De Brazza's monkey (''Cercopithecus neglectus'') is an Old World monkey endemic to the riverine and swamp forests of central Africa. The largest species in the guenon family, it is one of the most widespread arboreal African primates. Aside from ...
and Allen's swamp monkey. Some primates, such as the
rhesus macaque The rhesus macaque (''Macaca mulatta''), colloquially rhesus monkey, is a species of Old World monkey. There are between six and nine recognised subspecies that are split between two groups, the Chinese-derived and the Indian-derived. Generally ...
and gray langurs, can exploit human-modified environments and even live in cities.


Interactions between humans and other primates


Disease transmission

Close interactions between humans and non-human primates (NHPs) can create pathways for the transmission of zoonotic diseases. Viruses such as ''
Herpesviridae ''Herpesviridae'' is a large family of DNA viruses that cause infections and certain diseases in animals, including humans. The members of this family are also known as herpesviruses. The family name is derived from the Greek word ''ἕρπει� ...
'' (most notably Herpes B Virus), '' Poxviridae'', measles, ebola, rabies, the Marburg virus and
viral hepatitis Viral hepatitis is liver inflammation due to a viral infection. It may present in acute form as a recent infection with relatively rapid onset, or in chronic form. The most common causes of viral hepatitis are the five unrelated hepatotropic vi ...
can be transmitted to humans; in some cases the viruses produce potentially fatal diseases in both humans and non-human primates.


Legal and social status

Only
human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
s are recognized as persons and protected in law by the
United Nations The United Nations (UN) is an intergovernmental organization whose stated purposes are to maintain international peace and security, develop friendly relations among nations, achieve international cooperation, and be a centre for harmoniz ...
Universal Declaration of Human Rights. The legal status of NHPs, on the other hand, is the subject of much debate, with organizations such as the Great Ape Project (GAP) campaigning to award at least some of them legal rights. In June 2008, Spain became the first country in the world to recognize the rights of some NHPs, when its parliament's cross-party environmental committee urged the country to comply with GAP's recommendations, which are that chimpanzees,
orangutan Orangutans are great apes native to the rainforests of Indonesia and Malaysia. They are now found only in parts of Borneo and Sumatra, but during the Pleistocene they ranged throughout Southeast Asia and South China. Classified in the genu ...
s and
gorilla Gorillas are herbivorous, predominantly ground-dwelling great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four or fi ...
s are not to be used for animal experiments. Many species of NHP are kept as pets by humans, the Allied Effort to Save Other Primates (AESOP) estimates that around 15,000 NHPs live as exotic pets in the United States. The expanding Chinese middle class has increased demand for NHPs as exotic pets in recent years. Although NHP import for the pet trade was banned in the U.S. in 1975, smuggling still occurs along the United States – Mexico border, with prices ranging from US$3000 for monkeys to $30,000 for apes. Primates are used as model organisms in laboratories and have been used in space missions. They serve as
service animal Various definitions exist for a service animal. The Americans with Disabilities Act defines the term as "dogs that are individually trained to do work or perform tasks for people with disabilities". Dogs are the most common service animals, havi ...
s for disabled humans.
Capuchin monkey The capuchin monkeys () are New World monkeys of the subfamily Cebinae. They are readily identified as the " organ grinder" monkey, and have been used in many movies and television shows. The range of capuchin monkeys includes some tropical fores ...
s can be trained to assist
quadriplegic Tetraplegia, also known as quadriplegia, is defined as the dysfunction or loss of motor and/or sensory function in the cervical area of the spinal cord. A loss of motor function can present as either weakness or paralysis leading to partial or ...
humans; their intelligence, memory, and manual dexterity make them ideal helpers. NHPs are kept in zoos around the globe. Historically, zoos were primarily a form of entertainment, but more recently have shifted their focus towards conservation, education and research. GAP does not insist that all NHPs should be released from zoos, primarily because captive-born primates lack the knowledge and experience to survive in the wild if released.


Role in scientific research

Thousands of non-human primates are used around the world in research because of their psychological and physiological similarity to humans. In particular, the brains and eyes of NHPs more closely parallel human anatomy than those of any other animals. NHPs are commonly used in preclinical trials,
neuroscience Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, developme ...
,
ophthalmology Ophthalmology ( ) is a surgical subspecialty within medicine that deals with the diagnosis and treatment of eye disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a medic ...
studies, and toxicity studies.
Rhesus macaque The rhesus macaque (''Macaca mulatta''), colloquially rhesus monkey, is a species of Old World monkey. There are between six and nine recognised subspecies that are split between two groups, the Chinese-derived and the Indian-derived. Generally ...
s are often used, as are other macaques, African green monkeys, chimpanzees,
baboon 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 ...
s,
squirrel monkey Squirrel monkeys are New World monkeys of the genus ''Saimiri''. ''Saimiri'' is the only genus in the subfamily Saimirinae. The name of the genus is of Tupi origin (''sai-mirím'' or ''çai-mbirín'', with ''sai'' meaning 'monkey' and ''mirím'' ...
s, and marmosets, both wild-caught and purpose-bred. In 2005, GAP reported that 1,280 of the 3,100 NHPs living in captivity in the United States were used for experiments. In 2004, the
European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been de ...
used around 10,000 NHPs in such experiments; in 2005 in Great Britain, 4,652 experiments were conducted on 3,115 NHPs. Governments of many nations have strict care requirements of NHPs kept in captivity. In the US, federal guidelines extensively regulate aspects of NHP housing, feeding, enrichment, and breeding. European groups such as the European Coalition to End Animal Experiments are seeking a ban on all NHP use in experiments as part of the European Union's review of animal testing legislation.


Extinction threats

The
International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of nat ...
(IUCN) lists more than a third of primates as critically endangered or vulnerable. About 60% of primate species are threatened with extinction, including: 87% of species in Madagascar, 73% in Asia, 37% in Africa, and 36% in South and Central America. Additionally, 75% of primate species have decreasing populations. Trade is regulated, as all species are listed by CITES in Appendix II, except 50 species and subspecies listed in Appendix I, which gain full protection from trade. Common threats to primate species include
deforestation Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated ...
,
forest fragmentation Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processe ...
, monkey drives (resulting from primate crop raiding), and primate hunting for use in medicines, as pets, and for food. Large-scale tropical forest clearing is widely regarded as the process that most threatens primates. More than 90% of primate species occur in tropical forests. The main cause of forest loss is clearing for agriculture, although commercial logging,
subsistence A subsistence economy is an economy directed to basic subsistence (the provision of food, clothing, shelter) rather than to the market. Henceforth, "subsistence" is understood as supporting oneself at a minimum level. Often, the subsistence econo ...
harvesting of timber, mining, and dam construction also contribute to tropical forest destruction. In Indonesia large areas of lowland forest have been cleared to increase palm oil production, and one analysis of satellite imagery concluded that during 1998 and 1999 there was a loss of 1,000 Sumatran orangutans per year in the Leuser Ecosystem alone. Primates with a large body size (over 5 kg) are at increased extinction risk due to their greater profitability to poaching, poachers compared to smaller primates. They reach sexual maturity later and have a longer period between births. Populations therefore recover more slowly after being depleted by poaching or the pet trade. Data for some African cities show that half of all protein consumed in urban areas comes from the bushmeat trade. Endangered primates such as guenons and the Drill (mammal), drill are hunted at levels that far exceed sustainable levels. This is due to their large body size, ease of transport and profitability per animal. As farming encroaches on forest habitats, primates feed on the crops, causing the farmers large economic losses. Primate crop raiding gives locals a negative impression of primates, hindering conservation efforts. Madagascar, home to five endemic primate families, has experienced the greatest extinction of the recent past; since human settlement 1,500 years ago, at least eight classes and fifteen of the larger species have become extinct due to hunting and habitat destruction. Among the primates wiped out were ''Archaeoindris'' (a lemur larger than a silverback gorilla) and the families Palaeopropithecidae and Archaeolemuridae. In Asia, Hinduism, Buddhism, and Islam prohibit eating primate meat; however, primates are still hunted for food. Some smaller traditional religions allow the consumption of primate meat. The pet trade and traditional medicine also increase demand for illegal hunting. The
rhesus macaque The rhesus macaque (''Macaca mulatta''), colloquially rhesus monkey, is a species of Old World monkey. There are between six and nine recognised subspecies that are split between two groups, the Chinese-derived and the Indian-derived. Generally ...
, a model organism, was protected after excessive trapping threatened its numbers in the 1960s; the program was so effective that they are now viewed as a pest throughout their range. In Central and South America forest fragmentation and hunting are the two main problems for primates. Large tracts of forest are now rare in Central America. This increases the amount of forest vulnerable to edge effects such as farmland encroachment, lower levels of humidity and a change in plant life. Movement restriction results in a greater amount of inbreeding, which can cause deleterious effects leading to a population bottleneck, whereby a significant percentage of the population is lost. There are 21 critically endangered primates, 7 of which have remained on the IUCN's "The World's 25 Most Endangered Primates" list since the year 2000: the silky sifaka, Delacour's langur, the white-headed langur, the gray-shanked douc, the Tonkin snub-nosed monkey, the Cross River gorilla and the Sumatran orangutan. Miss Waldron's red colobus was recently declared extinct when no trace of the subspecies could be found from 1993 to 1999. A few hunters have found and killed individuals since then, but the subspecies' prospects remain bleak.


See also

* Arboreal theory * Great Ape Project * Human evolution * International Primate Day * List of primates * List of fossil primates * Monkey Day * Primatology


Footnotes


References


Literature cited

* * * *


Further reading

*


External links

*
Primate Info Net


at Animal Diversity Web
Primate Research Institute
Kyoto University
High-Resolution Cytoarchitectural Primate Brain Atlases

EUPRIM-Net: European Primate Network

PrimateImages: Natural History Collection

Interactive views
of various primate skeletons at eSkeletons.org (associated with the University of Texas at Austin)
Tree of Life web project
{{Featured article Primates, Extant Thanetian first appearances Taxa named by Carl Linnaeus