Sunday, 27 March 2016

Monkey

Monkeys are haplorhine dry-nosed primates, a paraphyletic group generally possessing tails and consisting of approximately 260 known living species. Many monkey species are tree-dwelling arboreal, although there are species that live primarily on the ground, such as baboons. Most species are also active during the day diurnal. Monkeys are generallyconsidered to be intelligent, particularly Old World monkeys.
Lemurs, lorises, and galagos are not monkeys; instead they are strepsirrhine wet-nosed primates. Like monkeys, tarsiersare haplorhine primates; however, they are also not monkeys. There are two major types of monkey: New World monkeys platyrrhines from South and Central America and Old World monkeyscatarrhines of the superfamily Cercopithecoidea from Africa and Asia. Hominoid apes gibbons, orangutans, gorillas, chimpanzees, and humans, which all lack tails, are also catarrhines but are not considered monkeys. Tailless monkeys may be called apes, incorrectly according to modern usage; thus the tailless Barbary macaque is sometimes called the Barbary ape. Because Old World monkeys are more closely related to hominoid apes than to New World monkeys, yet the term monkey excludes these closer relatives, monkeys are referred to as a paraphyletic group. Simians monkeys and tarsiers emerged within haplorrhines some 60 million years ago. New World monkeys and catarrhine monkeys emerged within the simians some 35 millions years ago. Old World monkeys and Hominoidea emerged within the catarrhine monkeys some 25 millions years ago. Extinct basal simians such as Aegyptopithecus or Parapithecus 35-32 million years ago are also considered monkeys by primatologists.
According to the Online Etymology Dictionary, the word "monkey" may originate in a German version of the Reynard the Foxfable, published circa 1580. In this version of the fable, a character named Moneke is the son of Martin the Ape. In English, no very clear distinction was originally made between "ape" and "monkey"; thus the 1910 Encyclopædia Britannica entry for "ape" notes that it is either a synonym for "monkey" or is used to mean a tailless humanlike primate. Colloquially, the terms "monkey" and "ape" are widely used interchangeably. Also, a few monkey species have the word "ape" in their common name, such as the Barbary ape
. ater in the first half of the 20th century, the idea developed that there were trends in primate evolution and that the living members of the order could be arranged in a series, leading through "monkeys" and "apes" to humans. Monkeys thus constituted a "grade" on the path to humans and were distinguished from "apes".
Scientific classifications are now more often based on monophyletic groups, that is groups consisting of all the descendants of a common ancestor. The New World monkeys and the Old World monkeys are each monophyletic groups, but their combination is not, since it excludes 

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