New World Monkeys

New World monkeys (Platyrrhini) are a group of primates that inhabit Central and South America. There are about 60 species of New World monkeys. Members of this group include marmosets, tamarins, capuchins, squirrel monkeys, night monkeys, owl monkeys, titis, sakis, uakaris, howler monkeys, spider monkeys, woolly spider monkeys, and woolly monkeys.

New World monkeys are small to medium in size. They are distinguished from their cousins the Old World monkeys by their flat nose—in fact, the name Platyrrhini means "flat nose". New World monkeys also differ from Old World monkeys in that all species are tree-dwelling (arboreal) primates. Only capuchins forage on the forest floor, but they are not truly adapted for life on the ground and spend much of their time up in the trees.

Many Old World monkey species have descended to the ground where they inhabit grasslands and other terrestrial habitats. The South American jungle habitat of New World monkeys though offers many arboreal niches and they have taken full advantage of that fact. New World monkeys exhibit a wide variation in lifestyles and diet.

New World monkeys have a variety of ways they get around. Most groups are quadrupedal climbers, but some groups such as the squirrel monkeys and capuchins, are squirrel-scamperers. Spider monkeys and woolly monkeys brachiate (swing from branch to branch using their arms) with the assistance of a prehensile tail.

The diThe diet of New World monkeys is varied. Most species are herbivorous (feeding on leaves, fruit, nuts, and gums) but some feed on insects as well. Diet varies between the subgroups of New World monkeys—tamarins and marmosets feed on insects and gum, howlers eat leaves and other plant matter and uakaris feed on fruit.

The New World monkeys diverged from the apes and Old World monkeys about 40 million years ago during the Cenozoic Era. Scientists believe that the ancestors of modern New World monkeys migrated from Africa to South America either by crossing the Atlantic Ocean on a vegetation raft or by wandering across a temporary land bridge that later became submerged (and isolated them). Once in the New World, this group was isolated and continued evolving separately from the lineage that went on to produce today's Old World monkeys and apes.

The New World monkeys include five subgroups, the Callitrichidae, Cebidae, aotidae, pitheciidae, and Atelidae. Classification of New World monkeys has been complicated by the fact that the fossil record for the group is rather sparse, with only a few hundred fossil fragments unearthed so far.

The Callitrichidae include marmosets, tamarins and lion tamarins. Members of this group are the smallest of the simian primates. They feed on fruit, gum, insects and sap.

The Cebidae include the capuchin monkeys and squirrel monkeys. Members of this group are small monkeys that feed on fruit and insects.

The Aotidae are the night monkeys (also referred to as the owl monkeys). Members of this group live in high elevation habitats and therefore have thicker fur than other monkeys. They are nocturnal and have large eyes which enable them to see better in low light.

The Pitheciidae include titis, saki monkeys and uakaris. Most members of this group inhabit the Amazon river basin in Brazil, although a few species are found in Columbia and Bolivia. Members of this group are small to medium sized monkeys and have long fur with contrasting coloration.

The Atelidae include howler monkeys, spider monkeys, woolly monkeys, and woolly spider monkeys. Members of this group inhabit forests throughout Central and South America. They are medium in size and have long prehensile tails. They move from branch to branch by swinging from their arms and tail (this locomotion method is called brachiation).