Primate
Primates[1] Temporal range: Late Cretaceous - Recent
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Olive Baboon, an Old World monkey | |
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Order: | Primates Linnaeus, 1758
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Range of the non-human primates |
A primate is any member of the biological order Primates (Latin: "prime, first rank"[2]), the group that contains all the species commonly related to the lemurs, monkeys, and apes, with the last category including humans.[3] Primates are found all over the world. Non-human primates occur mostly in Central and South America, Africa, and South Asia. A few species exist as far north in the Americas as southern Mexico, and as far north in Asia as northern Japan.
The Primates order is divided informally into three main groupings: prosimians, monkeys of the New World, and monkeys and apes of the Old World. The prosimians are species whose bodies most closely resemble that of the early proto-primates. The most well known of the prosimians, the lemurs, are located on the island of Madagascar and to a lesser extent on the Comoros Islands, isolated from the rest of the world. The New World monkeys include the familiar capuchin, howler, and squirrel monkeys. They live exclusively in the Americas. Discounting humans, the rest of the simians, the Old World monkeys and the apes, inhabit Africa and southern and central Asia, although fossil evidence shows many species existed in Europe as well.
According to fossil evidence, primitive ancestors of primates already existed in the late Cretaceous. Molecular clock studies suggest that the primate branch is even more ancient (originating at least in the mid-Cretaceous). They are now thought to be most closely related to flying lemurs and, more distantly, to treeshrews. They probably have descended from Plesiadapiformes.
Distinguishing features
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Primates have radiated in arboreal habitats and therefore retain many characteristics are adaptations to this environment. They can be either herbivorous or omnivorous. They are distinguished by their primitive (unspecialized) body plan, fingernails, colour vision, generalised dental pattern and postorbital bar. They have two mammary glands, 1-2 young per pregnancy and a long gestation and developmental period. Primates are frequently highly social, with flexible dominance hierarchies.[4] New World species form monogamous pair bonds, and show substantial paternal care of young unlike most Old World monkeys.
Anatomy and morphology
Skull and brain
Primates have two forward-facing eyes on the front on the skull, unlike many other mammals which have eyes on the side of the skull. The 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 human skull has a three-fold greater endocranial volume (inner surface of skull) than the volume of the greatest non-human primate, reflecting a larger brain size. The mean human endocranial volume is 1201 cm³, it is 469 cm³ in gorillas, 400 cm³ in chimpanzees and 397 cm³ in orangutans.[5] There is a tendency within primates towards reduction of the olfactory region of the brain and expansion of the cerebrum, especially the cerebral cortex. This is correlated with an increasing reliance on vision and increasingly complex social behavior.[6]
Eyes
Primates have forward-facing colour binocular vision. This allows overlapping fields of view, which give primates stereoscopic vision and accurate distance perception, which was useful for the brachiating ancestors of humans. Colour vision is important for finding and collecting food. Strepsirrhines have a postorbital bar, a bone which runs around the eyesocket, to protect their eyes, which is in contrast to the higher primates, haplorrhines, which have evolved fully enclosed sockets.[7]
Hands and feet
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All primates have five digits on each limb (pentadactyly), with keratin nails on the anterior ends. The ventral sides of the hands and feet have tactile pads on the distal phalanges. They have opposable thumbs, which are a characteristic primate feature, but are not limited to this order; opossums, for example, also have opposing thumbs. These thumbs allow some species to use tools to perform some tasks. In primates, the combination of opposing thumbs, short fingernails (rather than claws) and long, inward-closing fingers is a relic of the ancestral practice of gripping branches, and has, in part, allowed some species to develop brachiation as a significant means of transportation. Prosimians have clawlike nails on the second toes of their feet.
Limbs and vertebral column
The primate clavicle is retained as prominent element of the pectoral girdle, this allows the shoulder joint broad mobility. Apes have more mobile shoulder joints and arms due to the dorsal position of the scapula, broad ribcages that are flatter front-to-back, and a shorter, less mobile spine compared to Old World monkeys (with caudal vertebrae greatly reduced, resulting in tail loss in some species).
Prehensile tail
Old World monkeys are unlike apes in that most have tails, and unlike the New World monkeys in that their tails are never prehensile. Only the New World Atelidae family have prehensile tails.
Mouth and teeth
Primates have a shortened rostrum (snout).[4] Prosimians are distinguished by their immobilized upper lips, moist tip to their nose and forward-facing lower front teeth. Primates have a considerably varied dental pattern. Some primates have lost most of their incisors, although all retain at least one lower incisor. In most strepsirhines, the lower incisors form a toothcomb which is thought to be used in grooming and possibly foraging. Old World monkeys also have eight premolars, compared with twelve in New World monkeys. The Old World species are divided into apes and monkeys depending on the number of cusps on their molars (apes have five—the "Y-5" molar pattern, Old World monkeys have only four in a bilophodont pattern). A hypocone evolved in early primate history, while the paraconid was lost, leaving both upper and lower teeth with a basically quadrate pattern. Primitively, primate molars were brachydont and tuberculosectorial, but they have become bunodont and quadrate in a number of modern forms.[6]
Nose
Technically, the distinction of Old World monkeys from New World monkeys depends on the structure of the nose, and the distinction of Old World monkeys from apes depends on dentition. In New World monkeys the nostrils face sideways, whilst in Old World monkeys, they face downwards.
Physiology
Sexual dimorphism
Simians show some degree of sexual dimorphism. Old World species (apes and some monkeys) often exhibit sexual dimorphism, which can also be found to a lesser degree in some New World species. Recent studies have mainly used the technique of comparative analysis 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[8][9] and canine tooth size[10][11] along with pelage and skin colour.[12] The dimorphism in primates has been attributed to many factors:
- Mating system - Polygynous species are more sexually dimorphic than monogamous species, such as the New World monkeys.[13] It is also associated with greater male gonadal investment than what is found in closely related monogamous species.[14][15]
- Size - Larger species are more sexually dimorphic than smaller species.[13]
- Habitat - Terrestrial species tend to be more sexually dimorphic than arboreal species. It is possible that male-male competition in terrestrial species is more dependent on body size.
- Diet - Frugivores, for reasons that are not clear, are slightly more sexually dimorphic than folivores.[15] Energy may be less of a constraint, or maybe females may be more clumped around an area of fruit trees.
Comparative analyses have substantiated the sexual selection hypotheses, and have generated a more complete understanding of the relationship between sexual selection, natural selection, and mating systems in primates. Studies are helping to find the relative contribution of the various selective and non-selective mechanisms in sexual dimorphism evolution and expression.[16] These studies have shown that dimorphism is the product of changes in both male and female traits. Ontogenic scaling, where relative extension of a common growth trajectory occurs, may show some insight into the relationship between sexual dimorphism and growth patterns.[17] There is some evidence from the fossil record that suggests that there was convergent evolution of dimorphism, and some extinct hominids probably exceeded dimorphism of any living primate.
Color vision
Color vision in primates is unique in the evolution of most eutherian mammals. While our remote vertebrate ancestors possessed trichromacy, our nocturnal, warm-blooded, mammalian ancestors lost one of three cones in the retina at the time of dinosaurs. Fish, reptiles and birds are therefore trichromatic while all mammals, with the exception of some primates and marsupials,[18] are strictly dichromats.
Primates achieve trichromacy through color receptors (cone cells), with spectral peaks in the violet (short wave, S), green (middle wave, M), and yellow-green (long wave, L) wavelengths. All primates, however, are not capable of trichromacy. The catarrhines are routinely trichromatic, meaning that both males and females possess three opsins (pigments) sensitive to 430 nm, 530 nm, and 560 nm wavelengths.[19] Platyrrhines, on the other hand are non-routinely trichromatic; only a small population of platyrrhines are trichromats.[20]
Howler monkeys have reinvented routine trichromatism through a recent gene duplication of the red-green opsin gene.[21] This has allowed trichromacy for both sexes, the X chromosome has gained two loci to house both the green allele and the red allele. Howler monkeys are perhaps the most folivorous of the New World monkeys. Fruits are not part of their diet, and the type of leaves they consume (young, nutritive, and digestible), are detectable only by a red-green signal. Field work exploring the dietary preferences of howler monkeys suggest that routine trichromacy was environmentally selected for.[20]
Social systems
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Richard Wrangham proposed that social systems are best classified by the amount of movement by females occurring between groups.[22] He proposed 4 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 therefore the close association may be influential in affecting social behaviour. The groups formed are generally quite small. This organisation can be seen in chimpanzees, the males will cooperate in defending their territories.
- 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.
- Monogamous species - a male-female bond, sometimes accompanies by juvenile offspring. There is shared responsibility of parental care and territorial defence. The offspring will leave the parents territory during adolescence.
- Solitary species - often males who defend territories that include the home ranges of several females, found in the prosimians. Orangutans do not defend their territory but have the same organisation.
Primatologist Dr. Jane Goodall, who studied in the Gombe Streams National Park, noted fission-fusion societies in chimpanzees.[23] There is fission where 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 Hamadryas Baboons, Geladas, spider monkeys and Bonobos.
These social systems are affected by three main ecological factors; distribution of resources, group size and predation.[24] Within a social group there is a balance between cooperation and competition. Cooperation comes in the form of allogrooming; whereby ectoparasites are removed and wounds cleaned, food sharing and collective defence against predators or of a territory. Competition is demonstrated by aggression and may come about through availability of food, sleeping sites or mates. Aggression is often used in establishing social hierarchies.[24]
Locomotion
Various species of primates move by brachiation, bipedalism, leaping, arboreal and terrestrial quadrupedalism, climbing or knuckle walking.
Most prosimians are arboreal quadrupedalists and climbers. Many are also terrestrial quadrupedalists, while some are leapers. Most monkeys are both arboreal and terrestrial quadrupedalists and climbers. Gibbons are brachiators. Chimps, orangutans, and gorillas all knuckle walk, and can move bipedally for short distances. Humans are the only fully bipedal species.
Laughter
Laughter may not be confined or unique to humans, despite Aristotle's observation that "only the human animal laughs". But some behavioural psychologists argue that self-awareness of one's situation, or the ability to identify with somebody else's predicament, are prerequisites for laughter, so animals do not laugh like humans do.
Chimpanzees, gorillas, and orangutans show laughter-like vocalizations in response to physical contact, such as wrestling, play chasing, or tickling. This is documented in wild and captive chimpanzees. Chimpanzee laughter is not readily recognizable to humans as such, because it is generated by alternating inhalations and exhalations that sound more like breathing and panting. The differences between chimpanzee and human laughter may be the result of adaptations that have evolved to enable human speech. There are instances in which non-human primates have been reported to have expressed joy. One study analyzed and recorded sounds made by human babies and Bonobos (a species of chimpanzee) when they were tickled. It found although the Bonobo's laugh was a higher frequency, the laugh followed the same spectrographic pattern of human babies to include as similar facial expressions. Humans and chimpanzees share similar ticklish areas of the body such as the armpits and belly. The enjoyment of tickling in chimpanzees does not diminish with age.[25]
Habitat
Primates evolved from arboreal animals and many species live most their lives in trees. Other species are partially terrestrial, such as baboons and the Patas Monkey. Only a few species are fully terrestrial, such as the Gelada and Humans. Primates live in a diverse number of forested habitats, including rain forests, mangrove forests, and montane forests to altitudes of over 3000 m. Although most species are generally shy of water, a few are good swimmers and are comfortable in swamps and watery areas, including the Proboscis Monkey, De Brazza's Monkey and Allen's Swamp Monkey, which has developed small webbing between its fingers. Some primates, such as the Rhesus Macaque and the Hanuman Langur, can exploit human-modified environments and even live in cities.[citation needed]
Evolutionary history
Euarchontoglires |
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The Primate order lies in a tight clustering of related orders (the Euarchontoglires) within the Eutheria, a subclass of Mammalia. Recent molecular genetic research on primates, flying lemurs, and treeshrews has shown that the two species of flying lemur (Dermoptera) are more closely related to the primates than the treeshrews of the order Scandentia, even though the treeshrews were at one time considered primates. These three orders make up the Euarchonta clade. This clade combines with the Glires clade (made up of the Rodentia and Lagomorpha) to form the Euarchontoglires clade. Variously, both Euarchonta and Euarchontoglires are ranked as superorders. Also, some scientists consider Dermoptera a suborder of Primates and call the "true" primates the suborder Euprimates (Hoffstetter, 1978).[26]
Evolution
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In modern, cladistic reckonings, the Primate order is also a true clade. The suborder Strepsirrhini, the "wet-nosed" primates, split off from the primitive primate line about 63 million years ago (mya). The seven strepsirhine families are the four related lemur families and the three remaining families that include the lorises, the Aye-aye, the galagos, and the pottos.[1] Older classification schemes wrap the Lepilemuridae into the Lemuridae and the Galagidae into the Lorisidae, yielding a three-two family split instead of the four-three split as presented here.[1] Other lineages of lower primates inhabited Earth. During the Eocene, most of the northern continents were dominated by two dominant groups, the adapids and the omomyids. The former is considered a member of Strepsirrhini, but it does not have a tooth-comb like modern lemurs. The latter was related closely to tarsiers, monkeys, and apes. Adapids survived until 10 mya; omomyids on the other hand perished 20 million years earlier.
The Aye-aye is difficult to place in Strepsirrhini.[1] Its family, Daubentoniidae, could be a lemuriform primate and its ancestors split from lemur line more recently than the lemurs and lorises split, about 50 mya. Otherwise it is sister to all of the other strepsirrhines, in which case in evolved away from the main strepsirrhine line between 50 and 63 mya.
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The suborder Haplorrhini, the "dry-nosed" primates, is composed of two sister clades.[1] The prosimian tarsiers in family Tarsiidae (monotypic in its own infraorder Tarsiiformes), represent the most primitive division at about 58 mya. The Simiiformes infraorder contains the two parvorders: the New World monkeys in one, and the Old World monkeys, humans and the other apes in the other.[1] This division happened about 40 mya. However about 30 mya, three groups split from the main haplorrhine lineage. One group stayed in Asia and are closest in kin to the "dawn monkey" Eosimias. The second stayed in Africa, where they developed into the Old World primates. The third rafted to South America to become the New World monkeys. Mysteriously the aboriginal Asian Haplorrhini vanished from record once Africa collided with Eurasia 24 mya. Apes and monkeys spread into Europe and Asia. Close behind came lorises and tarsiers, also African castaways. The first hominid fossils were discovered in Northern Africa and date back 7 mya. Modern humans did not appear until 0.2 mya, eventually becoming the most prevalent primate and mammal on Earth.
The discovery of new species happens at a rate of a few new species each year, and the evaluation of current populations as distinct species is in flux. Colin Groves listed about 350 species of primates in Primate Taxonomy in 2001.[27] The recently published third edition of Mammal Species of the World (MSW3) lists 376 species.[1] But even MSW3's list falls short of current understanding as its collection cutoff was in 2003, and a number publications since then have pushed the number of species up to 405. Notable new species not listed in MSW3 include the Bemaraha Woolly Lemur (Avahi cleesei) (named after British actor and lemur enthusiast John Cleese) and the GoldenPalace.com Monkey (whose name was put up for auction).
Classification
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- ORDER PRIMATES
- Suborder Strepsirrhini: non-tarsier prosimians
- Infraorder Lemuriformes
- Superfamily Cheirogaleoidea
- Family Cheirogaleidae: dwarf lemurs and mouse-lemurs (30 species)
- Superfamily Lemuroidea
- Family Lemuridae: lemurs (19 species)
- Family Lepilemuridae: sportive lemurs (22 species)
- Family Indriidae: woolly lemurs and allies (14 species)
- Superfamily Cheirogaleoidea
- Infraorder Chiromyiformes
- Family Daubentoniidae: Aye-aye (1 species)
- Infraorder Lorisiformes
- Infraorder Lemuriformes
- Suborder Haplorrhini: tarsiers, monkeys and apes
- Infraorder Tarsiiformes
- Family Tarsiidae: tarsiers (8 species)
- Infraorder Simiiformes
- Parvorder Platyrrhini: New World monkeys
- Family Cebidae: marmosets, tamarins, capuchins and squirrel monkeys (56 species)
- Family Aotidae: night or owl monkeys (douroucoulis) (7 species)
- Family Pitheciidae: titis, sakis and uakaris (41 species)
- Family Atelidae: howler, spider and woolly monkeys (24 species)
- Parvorder Catarrhini
- Superfamily Cercopithecoidea
- Family Cercopithecidae: Old World monkeys (135 species)
- Superfamily Hominoidea
- Family Hylobatidae: gibbons or "lesser apes" (13 species)
- Family Hominidae: humans and other great apes (7 species)
- Superfamily Cercopithecoidea
- Parvorder Platyrrhini: New World monkeys
- Infraorder Tarsiiformes
- Suborder Strepsirrhini: non-tarsier prosimians
The order Primates was established by Carl Linnaeus in 1758, in the tenth edition of his book Systema Naturae,[28] for the genera Homo (humans), Simia (other apes and monkeys), Lemur (prosimians) and Vespertilio (bats). In the first edition of the same book (1735), he had used the name Anthropomorpha for Homo, Simia and Bradypus (sloths).[29] In 1839, Henri-Marie Ducrotay de Blainville, following Linnaeus and imitating his nomenclature, established the orders Secundates (including the suborders Chiroptera, Insectivora and Carnivora), Tertiates (or Glires) and Quaternates (including Gravigrada, Pachydermata and Ruminantia),[30] but these new taxa were not accepted.
In older classifications, the Primates were divided into two superfamilies: Prosimii and Anthropoidea. The Prosimii included all of the prosimians: all of Strepsirrhini plus the tarsiers. The Anthropoidea contained all of the simians.
Primate hybrids
Primate hybrids usually arise in captivity[31] though there have been examples of primate hybrids in the wild.[32] Hybridisation occurs where two species' territories overlap, these hybrid zones may be created by humans when animals are placed in zoos or may be due to environmental pressures such as predation.[32] In The variation of animals and plants under domestication Charles Darwin noted: "Several members of the family of Lemurs have produced hybrids in the Zoological Gardens."[33]
Many gibbons are hard to identify based on fur coloration and are identified either by song or genetics.[31] These morphological ambiguities have led to hybrids in zoos. Zoos often receive gibbons of unknown origin and therefore rely on morphological variation or labels that are impossible to verify to assign species and subspecies names so it is common for separate species of gibbons to be misidentified and housed together. Interspecific hybrids, hybrids within a genus, also occur in wild gibbons where the ranges overlap.[34]
Intergeneric hybridizations, hybrids of a different genus, have been found in the wild. Though belonging to genera that have been distinct for several million years interbreeding still occurs between Geladas (Theropithecus gelada) and Hamadryas Baboon (Papio hamadryas).[35]
Legal status
Humans are recognized as persons and protected in law by the United Nations Universal Declaration of Human Rights[36] and by all governments, though to varying degrees. Non-human primates are not classified as persons. The status of non-human primates has generated much debate, particularly through the Great Ape Project [37] which argues for the personhood of the non-human members of the family Hominidae. In 1995 Ignaas Spruit, director of Leiden (Netherlands) based Pro-Primates organization, went farther, as he proposed that some rights should be recognized to all non-human primates.[38] In the same way, the American anthropologist Earnest Albert Hooton, enlarging the sense of the famous quote by Terence, used to say "Primas sum: primatum nil a me alienum puto", that is to say: “I am a primate; nothing about primates is outside of my bailiwick”.[39]
Animal testing
Thousands of primates are used every year around the world in scientific experiments because of their psychological and physiological similarity to humans. Chimpanzees, baboons, marmosets, macaques, and green monkeys are most commonly used in these experiments. In the European Union, around 10,000 were used in 2004, with 4,652 experiments conducted on 3,115 non-human primates in the UK alone in 2005.[40] As of 2004, 3,100 non-human primates were living in captivity in the United States, in zoos, circuses, and laboratories, 1,280 of them being used in experiments.[37] European campaign groups such as the BUAV are seeking a ban on all primate use in experiments as part of the European Union's current review of existing law on animal experimentation.
See also
References
- ^ a b c d e f g Groves, C. P. (2005). Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. pp. 111–184. ISBN 0-801-88221-4. OCLC 62265494.
- ^ From Old French or French primat, from a noun use of Latin primat-, from primus (“‘prime, first rank’”). The English singular primate was derived via back-formation from the Latin inflected form. Linnaeus thought this the "highest" order of mammals)
- ^ M. Goodman, D. A. Tagle, D. H. Fitch, W. Bailey, J. Czelusniak, B. F. Koop, P. Benson, J. L. Slightom (1990). "Primate evolution at the DNA level and a classification of hominoids". Journal of Molecular Evolution. 30: 260–266. doi:10.1007/BF02099995.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ a b "Palæos Vertebrates 480.400 Archonta Primates". 2006-01-08.
{{cite web}}
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ignored (help) - ^ Aiello, L. & Dean, C. (1990). An Introduction to Human Evolutionary Anatomy. Academic Press. p. 193. ISBN 0120455900.
{{cite book}}
: CS1 maint: multiple names: authors list (link) - ^ a b Myers, P. (1999). "AWD: Primates: Information".
{{cite web}}
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ignored (help) - ^ Campbell, Bernard G., Loy, James D. (2000). Humankind Emerging (8th edition). Allyn & Bacon. p. 85.
{{cite book}}
: CS1 maint: multiple names: authors list (link) - ^ Ralls, K (1976). "Mammals in Which Females are Larger Than Males". The Quarterly Review of Biology. 51 (2): 245. doi:10.1086/409310.
- ^ Lindstedtand & Boyce (1985). "Seasonality, Fasting Endurance, and Body Size in Mammals". Am Nat. 125: 873. doi:10.1086/284385.
- ^ Frisch, J. E. (1963). "Sex-differences in the canines of the gibbon (Hylobates lar)". Primates. 4 (2): 1. doi:10.1007/BF01659148.
- ^ Kay, R. F. (1975). "The functional adaptations of primate molar teeth". 43 (2): 195–215.
{{cite journal}}
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(help) - ^ Crook (1972). "Sexual selection, dimorphism, and social organization in the primates". Sexual selection and the descent of man.
- ^ a b Cheverud, J.M., Dow, M. M. & Leutenegger, W. (1985). "The quantitative assessment of phylogenetic constraints in comparative analyses: Sexual dimorphism in body weight among primates". Evolution. 39 (6): 1335–1351. doi:10.2307/2408790.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ Luetenegger, W. (1978). "Scaling of sexual dimorphism in body size and breeding system in primates". Nature. 272: 610–611. doi:10.1038/272610a0.
- ^ a b Leutenegger,W. & Cheverud, J. M. (1982). "Correlates of sexual dimorphism in primates: Ecological and size variables". International Journal of Primatology. 3 (4): 387. doi:10.1007/BF02693740.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ Plavcan, J.M. (2001). "Sexual dimorphism in primate evolution". Am J Phys Anthropol. 33: 25–53. doi:10.1002/ajpa.10011.
- ^ O'Higgins, P. & Collard, M. (2002). "Sexual dimorphism and facial growth in papionin monkeys". Journal of Zoology. 257 (2): 255–272. doi:10.1017/S0952836902000857.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ Arrese, C. A.; et al. (2005). "Cone topography and spectral sensitivity in two potentially trichromatic marsupials, the quokka (Setonix brachyurus) and quenda (Isoodon obesulus)". Proc. Biol. Sci. 272 (1565): 791–796. doi:10.1098/rspb.2004.3009.
{{cite journal}}
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(help) - ^ Bowmaker, J. K., and S. Astell (1991). "Photosensitive and photostable pigments in the retinae of Old World monkeys". J Exp Biol. 156: 1–19.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ a b Surridge, A. K., and D. Osorio (2003). "Evolution and selection of trichromatic vision in primates". Trends in Ecol. and Evol. 18: 198–205. doi:10.1016/S0169-5347(03)00012-0.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ Lucas, P. W., and N. J. Dominy (2003). "Evolution and function of routine trichromatic vision in primates". Evolution. 57: 2636–2643. doi:10.1554/03-168.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ Wrangham, R. W. (1982). "Mutualism, kinship and social evolution". Current Problems in Sociobiology. Cambridge University Press. ISBN 0521242037.
- ^ Constable, J. L.; et al. (2001). "Noninvasive paternity assignment in Gombe chimpanzees". Molecular Ecology. 10 (5): 1279–1300.
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: Explicit use of et al. in:|author=
(help) - ^ a b Pough, F. W., Janis, C. M. & Heiser, J. B. (2005). "Primate Societies". Vertebrate Life (7th edition ed.). Pearson. pp. 621–623.
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:|edition=
has extra text (help)CS1 maint: multiple names: authors list (link) - ^ Johnson, Steven (2003). "Emotions and the Brain". Discover. 24 (4).
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ignored (help) - ^ McKenna, Malcolm C. and Bell, Susan K. (1997). Classification of Mammals Above the Species Level. Columbia University Press, New York. p. 329.
{{cite book}}
: CS1 maint: multiple names: authors list (link) - ^ Primate Taxonomy (Smithsonian Institute Press, 2001), Colin Groves (ISBN 1-56098-872-X )
- ^ Linnaeus, Carolus (1758). Sistema naturae per regna tria Naturae, secundum classes, ordines, genera, species, cum characteribus differentiis, synonimis locis. Tomus I. Impensis direct. Laurentii Salvii, Holmia. pp. pp. 20-32.
{{cite book}}
:|pages=
has extra text (help) - ^ Linnaeus, Carolus (1735). Sistema naturae sive regna tria Naturae systematice proposita per classes, ordines, genera, & species. apud Theodorum Haak, Lugduni Batavorum. pp. pp. s.p.
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has extra text (help) - ^ Blainville, Henri-Marie Ducrotay de (1839). "Nouvelle classification des Mammifères". Annales Françaises et Etrangères d’Anatomie et de Physiologie Appliquées à la Médicine et à l’Histoire Naturelle, 3. pp. pp. 268-269.
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has extra text (help) - ^ a b Tenaza, R. (1984). "Songs of hybrid gibbons (Hylobates lar × H. muelleri)". American Journal of Primatology. 8 (3): 249–253. doi:10.1002/ajp.1350080307.
- ^ a b Bernsteil, I. S. (1966). "Naturally Occurring Primate Hybrid". Science. 154 (3756): 1559–1560. doi:10.1126/science.154.3756.1559.
- ^ Darwin, C (1868). The variation of animals and plants under domestication. Vol. 2 (1st edition ed.). London: John Murray. p. 153.
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:|edition=
has extra text (help) - ^ Sugawara, K. (1979). "Sociological study of a wild group of hybrid baboons between Papio anubis and P. hamadryas in the Awash Valley, Ethiopia". Primates. 20 (1): 21–56. doi:10.1007/BF02373827.
- ^ Jolly, C. J.; et al. (1997). "Intergeneric Hybrid Baboons". International Journal of Primatology. 18 (4): 597–627. doi:10.1023/A:1026367307470.
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: Explicit use of et al. in:|author=
(help) - ^ UN Declaration of Human Rights
- ^ a b Declaration on Great Apes, Great Ape Project
- ^ Spruit, Ignaas (1995). "On Declaring Non-human Primate Rights: An Approach to Primate Protection". In Corbey, Raymond and Theunissen, Bert (ed.). Ape, Man, Apeman: Changing Views since 1600. Department of Prehistory, Leiden University. pp. pp. 377-383.
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has extra text (help)CS1 maint: multiple names: editors list (link) - ^ Hooton, Earnest (1955). "The Importance of Primate Studies in Anthropology". In Gavan, J.A. (ed.). The Non-Human Primates and Human Evolution. Wayne University Press, Detroit. pp. pp. 1-10.
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has extra text (help) - ^ British Union for the Abolition of Vivisection - Primates
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