PRIMATE

in zoology, any member of the mammalian order Primates, which includes the prosimians, monkeys, apes, and man. The order has long excited human interest, because it contains man's closest relatives. The obvious similarity of monkeys and apes to man was noted long before any genetic relationship was postulated. Recognizing that monkeys possess intelligence substantially exceeding that of other familiar mammals, man has valued these animals as companions and pets for centuries. In recent decades, in addition to becoming increasingly popular as pets, nonhuman primates have served as substitutes for man in situations, such as experimental medicine and space science, which require near-human biological reactions. The two main groups of the order Primates are the prosimians (lemurs, lorises, and tarsiers) and the anthropoids (monkeys, apes, and man). As classified at present, the suborder Prosimii consists of six families; the Tupaiidae (tree shrews, though these are considered by some authorities to belong in the order Insectivora), Lemuridae (lemurs), Indriidae (indri, sifaka, and avahi), Daubentoniidae (aye-aye), Lorisidae (galagos and lorises), and Tarsiidae (tarsiers). Collectively, the prosimian suborder is frequently referred to as lower primates. The suborder Anthropoidea, sometimes called "higher" primates, also comprises six families: Callitrichidae (marmosets and tamarins), Cebidae (South American monkeys other than marmosets), Cercopithecidae (African and Asian monkeys), Hylobatidae (lesser apes: siamangs and gibbons), Pongidae (great apes: orangutan [orangutan], gorilla, and chimpanzee), and Hominidae (men, living and extinct). The two geographically separated stocks, the Old World and the New World monkeys, are often referred to as catarrhines and platyrrhines, respectively, terms which derive from the shape of the nose (see below Form and function). in zoology, a member of the mammalian order Primates, which comprises two suborders: the prosimians (lemurs, lorises, and tarsiers) and the anthropoids (monkeys, apes, and man). According to fossil records, primates originated in the Late Cretaceous (97.5 to 66.4 million years ago) as forest-dwelling creatures. Evidence that modern man is a descendant of these early primates was first provided by Charles Darwin in his Origin of Species, published in 1859. The anatomical and behavioral features that distinguish primates from members of other mammalian orders include a lack of strong specialization in structure; prehensile hands and feet, usually with opposable thumbs and great toes; flattened nails instead of claws on the digits; acute vision with some degree of binocular vision; relatively large brain exhibiting a degree of cortical folding; and prolonged postnatal dependency. No primate exhibits all these features, and indeed the diversity of primate forms has produced disagreement as to their proper classification. Taxonomically the primate order can be arranged in 11 families: The prosimians include the lemurs (Lemuridae), the aye-aye (a single species comprising the Daubentoniidae), galagos and lorises (Lorisidae), tarsiers (Tarsiidae), and a little-known group of arboreal creatures including the avahi, sifaka, and indri (Indriidae). The anthropoids include marmosets and tamarins (Callitrichidae), South American monkeys other than marmosets (Cebidae), African and Asian monkeys (Cercopithecidae), siamangs and gibbons (Hylobatidae, the lesser apes), orangutans, gorillas, chimpanzees (Pongidae, the great apes), and man and his direct ancestors (Hominidae). The tree shrews (Tupaiidae) are included among the prosimians by some authorities but by others among the insectivores. Male gorilla (Gorilla gorilla). A wide range of size, weight, and habitat is found among members of the primate order. The smallest primates are weighed in tens of grams, while the gorilla (Gorilla gorilla; see photograph) typically weighs 140 to 180 kg (300 to 400 pounds). Nonhuman primates are found throughout the tropical areas of India, Africa, Asia, and South America. A few species also live in temperate latitudes, but lack of winter food supply limits their adaptability to these climates. The combination of an unspecialized physical structure and highly specialized behaviour has made the primates a very successful order. An unspecialized structure helps primates flourish in changing environments, while their well-developed brains allow them to adapt their behaviour to suit their specific needs. Most primates have binocular vision and forward-facing eyes, two characteristics that are necessary for depth perception. Although their vision is highly developed, primates have shortened muzzles and a correspondingly reduced sense of smell. These modifications are a reflection of the predominantly arboreal life that has long characterized primates. Except for two species, all primates have five digits on each hand and foot. All have prehensile (grasping) hands, and all except man have prehensile feet. Although the opposable (freely moving) thumb is present in most primates, it is particularly developed in man, making him capable of delicate manipulation. One of the striking features of the primate order, wherein it differs from other mammalian orders, is that its existing members fall into a graded series, or scale of organization, which suggests an actual evolutionary trend leading from the most primitive (tree shrews) to the most advanced (humans). A trend in primate evolution has been toward a more elaborate brain. In higher primates the neocortex functions to receive, analyze, and synthesize information from the senses. The brain of anthropoids is larger, relative to body weight, than that of prosimians and is characterized by a complicated pattern of folds and fissures on the surface. Another evolutionary trend in primates involves the development of offspring both before and after birth. Gestation periods are relatively long, allowing for the development of the more complex brain. The more sophisticated species also exhibit longer infant and juvenile stages, which are probably related to the time required for their more advanced mental development and their integration into complex social systems. The reproductive cycle of copulation, gestation, birth, and lactation occupies the higher female primates for a year or more. The female does not usually come into estrus again until the offspring of the previous pregnancy is weaned. Primate infants are generally born fully furred and with their eyes open. Except in the case of man, chimpanzee, and gorilla, the newborns are able to cling to the mother's fur and need no support. Physical dependency ends when the young are weaned, but it is followed by an extended period of psychological maternal dependency lasting from 2 1/2 years in lemurs to 14 years or so in man. Primates exhibit four different forms of locomotion: vertical clinging and leaping; quadrupedalism, which involves use of both the forelimbs and the hind limbs in walking, climbing, and swinging; brachiation, in which the primary form of movement is swinging by the forelimbs; and bipedalism, the upright striding of man. All primates are able to sit upright, many can stand upright, and some can even walk upright for short periods, but only man is capable of the upright striding gait. Primates are omnivorous, and their teeth are multipurpose, allowing them to cut, tear, and grind. Although nonhuman primates will occasionally eat the flesh of other mammals, their diet consists primarily of leaves, fruit, bark, nuts and other vegetable matter, birds, eggs, rodents, insects, and frogs. For centuries man has recognized the superior intelligence of monkeys and has valued them as pets. Because the biology of all primates is very similar, nonhuman species have become increasingly important to man in medical research and space science. More than a quarter of a million wild monkeys are used in laboratories every year. Although most primates are still plentiful in the wild, certain species, including the orangutan and gorilla, are in danger of extinction from hunting, poaching, or loss of habitat. in Christianity, an ecclesiastical title for a bishop in some churches who has precedence over a number of other bishops. In the early church, it was one of several titles, including metropolitan, exarch, and patriarch, used to designate a chief bishop who had certain rights of superintendence over an entire district or area. Through gradual development it became primarily an honorary office. In the modern Roman Catholic church, primates are those metropolitan archbishops whose sees, by reason of antiquity or prominence, are the primary sees of a region or nation. Apart from the special case of the pope, who has among his titles that of primate of Italy, primates generally do not possess any jurisdiction outside their own dioceses, but only a limited and honorary right to precedence. In the Church of England, the archbishop of York is primate of England, whereas the archbishop of Canterbury is primate of the entire Anglican Communion. Additional reading General works J.R. Napier and P.H. Napier, A Handbook of Living Primates: Morphology, Ecology and Behaviour of Nonhuman Primates (1967), a comprehensive, technical book with one or more photographs of each genus; W.C. Osman Hill, Primates: Comparative Anatomy and Taxonomy, 8 vol. (1953-74), also technical and heavily illustrated, treating the primates in greater depth; W.E. Le Gros Clark, The Antecedents of Man, 3rd ed. (1971), a readable scientific account of nonhuman primates; F. Wood Jones, Arboreal Man (1916, reissued 1964), a classic work that contains much useful information; I.T. Sanderson, The Monkey Kingdom (1957, reissued 1963), an extensively illustrated popular book; I. Devore (ed.), Primate Behavior (1965); and C.R. Carpenter, Naturalistic Behavior of Nonhuman Primates (1964), two technical works on primate ethology; W.W. Howells, Mankind in the Making, rev. ed. (1967), an informative book on human evolution for the general reader; S. Zuckerman, Functional Affinities of Man, Monkeys, and Apes (1933), a technical dissertation on primate structure; Ian Tattersall, The Primates of Madagascgar (1982), a survey of many lower primates; and G.A. Doyle, The Study of Prosimian Behavior (1979). Tree shrews W.E. Le Gros Clark, "The Myology of the Tree-Shrew (Tupaia minor)," 1924:461-497; "On the Brain of the Tree-Shrew (Tupaia minor)," 1924:1053-1074; "On the Skull of Tupaia," 1925:559-567; and "On the Anatomy of the Pen-Tailed Tree Shrew (Ptilocercus lowii)," 1926: 1179-1309, all in the Proc. Zool. Soc. Lond. (1924-26), four important papers on tree shrews; R.D. Martin, "Treeshrews: Unique Reproductive Mechanism of Systematic Importance," Science, 152:1402-1404 (1966); and M.W. Sorenson and C.H. Conaway, "Observations on the Social Behaviour of Tree Shrews in Captivity," Folia Primatologica, 4:124-145 (1966), two technical papers. Tarsioids W.E. Le Gros Clark, "Notes on the Living Tarsier (Tarsius spectrum)," Proc. Zool. Soc. Lond., 1924:217-223 (1924); and H.H. Woollard, "The Anatomy of Tarsius spectrum," ibid., 1925:1071-1184 (1925), technical papers concerned with the relationships of tarsiers; H. Sprankel, "Untersuchungen an Tarsius. I. Morphologie des Schwanzes nebst ethologischen Bermerkungen," Folia Primatologica, 3:153-188 (1965), a summary, in German, of information on the taxonomy of tarsioids. Lemuroids J.J. Petter, Recherches sur l'cologie et l'thologie des Lmuriens malgaches (1962); "Ecological and Behavioral Studies of Madagascar Lemurs in the Field," Ann. N.Y. Acad. Sci., 102:267-281 (1962); and "The Lemurs of Madagascar," in I. Devore (ed.), Primate Behavior (1965), technical works on a variety of lemurs; A. Jolly, Lemur Behavior (1966), a readable, semipopular account, based on personal observations; A. Walker, "Patterns of Extinction Among the Subfossil Madagascan Lemuroids," in P.S. Martin and H.E. Wright (eds.), Pleistocene Extinctions (1967), a technical discussion of lemur evolution. New World monkeys R.I. Pocock, "On the External Characters of the South American Monkeys," Proc. Zool. Soc. Lond., 1920:91-113 (1920); and C.R. Carpenter, "Behavior of Red Spider Monkeys in Panama," J. Mammal., 16:171-180 (1935), two technical articles; L.A. Rosenblum and R.W. Cooper (eds.), The Squirrel Monkey (1968), a detailed account of the biology of one species; A. Cabrera, Catalogo de los mamiferos de America del Sur, 2 vol. (1957-61), a broad treatment, in Spanish, of the taxonomy and distribution of South American monkeys; P. Hershkovitz, "Mammals of Northern Colombia; Preliminary Report No. 4: Monkeys (Primates), with Taxonomic Revisions of Some Forms," Proc. U.S. Natn. Mus., 98:323-427 (1951), a scientific treatment of some South American forms. Old World monkeys R.I. Pocock, "The External Characters of the Catarrhine Monkeys and Apes," Proc. Zool. Soc., Lond., 1925:1479-1579 (1925); and "The Monkeys of the Genera Pithecus (or Presbytis) and Pygathrix Found to the East of the Bay of Bengal," ibid., 1934:895-961 (1934), two articles providing much technical information on the langur; C. G. Hartman and W.L. Strauss (eds.), The Anatomy of the Rhesus Monkey, Macaca mulatta (1933, reprinted 1971), a detailed account of the morphology of this important species; J.R. and P.H. Napier (eds.), Old World Monkeys (1970), a technical but comprehensive account of the catarrhines; N.C. Tappen, "Problems of Distribution and Adaptation of the African Monkeys," Curr. Anthrop., 1:91-120 (1960), a scientific account of the zoogeography of the catarrhines. Anthropoid apes C.F.M. Sonntag, The Morphology and Evolution of the Apes and Man (1924), a comprehensive and technical book, with many illustrations; R.M. and A.W. Yerkes, The Great Apes (1929, reissued 1970), a classic work, written for the general reader; C.R. Carpenter, A Field Study in Siam of the Behavior and Social Relations of the Gibbon (Hylobates lar) (1941, reprinted 1984); G.B. Schaller, The Mountain Gorilla (1963, reprinted 1988); and J. van Lawick-Goodall, In the Shadow of Man (1971), three readable accounts of the lives of individual species, based on extensive field work; V. Reynolds, The Apes (1967); and R. and D. Morris, Men and Apes (1966), well-illustrated popular books; C.P. Groves, "Population Systematics of the Gorilla," J. Zool., 161:287-300 (1970); and Gorillas (1970), respectively, a technical and popular work on this interesting ape; W.K. Gregory, The Anatomy of the Gorilla: The Studies of Henry Cushier Raven (1950), a carefully illustrated, technical book; Ted Crail, Apetalk and Whalespeak: The Quest for Interspecies Communication (1981). J.R. Napier Evolution and paleontology Renewed interest in primate origins Beginning in the 1950s there was a notable expression of interest in primate paleontology. Since then, hardly a year has passed without the announcement of some new major discovery. New sites have been opened up and old discoveries redescribed and reallocated. New techniques in geological dating, in palynology (the study of fossil pollen), in paleoclimatology and paleoecology and in the archeological interpretation of fossil sites, have helped to lift primate paleontology into the forefront of the life sciences and have aroused public interest to an unprecedented level. The popularity of all aspects of the evolution of man is reflected, for instance, in the spate of books covering this field published during this period. The African continent has contributed the greatest share of significant early finds-Rusinga and Songhor in Kenya, Olduvai in Tanzania, and Sterkfontein, Kromdraai, Swartkrans, Makapan in South Africa are names with which every anthropology student is familiar. Later, the names Omo, Kanapoi, Lothagam, Napak, Moroto, Laetoli, and Hadar-all East African sites of hominid and pongid discoveries in the 1970s and '80s-became equally well known. Elsewhere, pieces of this colossal worldwide jigsaw have been discovered in Europe, notably in Hungary, France, and Italy; in the Siwalik Hills of northwest India; in the ever prolific middle Eocene Bridger Beds of North America; and in Colombia and Bolivia. These latter discoveries were particularly welcome because of the poverty of fossils of New World monkeys. While new discoveries have clarified the human story, older ones, that had only served to cloud it, have been repudiated. Piltdown man was shown unequivocally to be a fake in 1953; Oreopithecus of Monte Bamboli, Italy, has been relegated to a family remote from human ancestry, and Galley Hill Man in England has been shown to be a recent intrusion (a burial) into middle Pleistocene gravels. The questionable finds from the remoter geological period of the Eocene and Oligocene have also been re-examined, with the result that a number of confusing fossils have been dismissed. Anagale, long thought to be a fossil tree shrew, is now regarded as a small carnivore; others, such as the supposed tarsioid-anthropoid annectent form, Parapithecus fraasi, have been reallocated within the order Primates. Progress in constructing the phylogeny of higher primates and man has been bedevilled by a number of controversies concerning taxonomy and nomenclature, and, as a result, internal disagreements have developed which mitigate against the sort of international cooperation that is essential for so vast a project as the construction of a human phylogeny. New-school and old-school taxonomists have come into conflict. But with the rapid advances in genetics, in the new concepts of biological species and in population anthropology, a fresh equilibrium is slowly being acquired, as the pendulum swings between the reactionary "lumping" of such taxa as genera and the traditional "splitting," in which every new discovery was provided with a new generic name. The most extreme example of taxonomic lumping in primate paleontology was in a 1965 revision by E.L. Simons and D.R. Pilbeam of the Miocene-Pliocene genus Dryopithecus; from the 28 genera recognized prior to 1965, the authors recommended the recognition of three genera only: Dryopithecus, Ramapithecus, and Gigantopithecus. All the rest were absorbed into the three genera, a result initially satisfying but not yet subjected to the test of time. The primate fossil record Cretaceous The known range of the primate order was extended back from the middle Paleocene to the Late Cretaceous (about 75,000,000 years ago) by the discovery in Montana of one premolar and four molar teeth, representing two species of insectivore-like primates that were assigned in 1965 to a new genus, Purgatorius. This diagnosis is based on the characters of four molar and one premolar tooth and is not by any means universally accepted.