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Chapter Seven. The Living Primates. The Primate Order. Primates are best defined in terms of their adaptability , which is a response to the arboreal habitat. Primates are characterized by body flexibility and have a greater range of motion than most other mammals.
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Chapter Seven The Living Primates
The Primate Order • Primates are best defined in terms of their adaptability, which is a response to the arboreal habitat. • Primates are characterized by body flexibility and have a greater range of motion than most other mammals. • Pentydactylism, grasping, and opposable thumbs characterize most primates. • Fingers and toes end in nails, and the ends of fingers and toes have tactile pads. • The sense of smell is reduced but the visual sense is enhanced. There is a complete eye socket. • Primates show a great deal of behavioral flexibility and the ability to learn from experience.
Growth and Development • The primates are characterized by the prolongation of gestation, during which the fetus grows rapidly. • Primates are also characterized by a long childhood period and a prolonged life span.
The Living Primates • The primate order is divided into 2 suborders, which is further divided into 2 infraorders. [Refer to Table 7-3: Classification of Living Primates]
The Lemuriformes • Most lemuriformes are nocturnal, with eyes adapted for night vision. Their sense of smell is well-developed. • All prosimians possess second toes that end in grooming claws. • In most prosimians, the lower front teeth are thin and narrow and project forward, forming a dental comb.
The Tarsiiformes • Tarsiers are very small primates. • Their name is derived from their elongated tarsal (ankle) bones, which enable them to leap long distances. • Tarsiers possess grooming claws, but lack a dental comb. • Tarsiers are strictly nocturnal, with very large eyes.
New World Monkeys • New World monkeys tend to be smaller than those of the Old World, and have a platyrrhine nose. • They are strictly arboreal and some have a prehensile tail. • New World monkeys are divided into two groups • the Callatrichidae (marmosets and tamarins) • the Cebidae
The Infraorder Catarrhini • The Old World monkeys, apes and humans make up the infraorder Catarrhini. • This group is characterized by the catarrhine nose, two premolars per quadrant of the mouth, and a well-developed thumb that in most cases is opposable. • This infraorder is divided into two superfamilies. • Cercopithecoidea is composed of the Old World monkeys. • Hominoidea includes the apes and humans.
Old World Monkeys • The Old World monkeys are divided into two groups. • The Cercopithecinae • Exhibit sexual dimorphism, have ischial callosities, and sexual skin • Some of these monkeys are terrestrial • The Colobinae • the leaf-eating monkeys
The Apes (Superfamily: Hominoidea) • The family Hylobatidae includes the gibbons and siamangs, sometimes called the lesser apes or small-bodied aped. • The family Hominidae contains all of the great apes. • Orangutans belong to the subfamily Ponginae and the gorillas belong to the subfamily Gorillinae. • The subfamily Homininae contains the chimpanzees, bonobos and humans. • Chimpanzees and bonobos belong to the tribe Panini while humans belong to the tribe Hominini.