Physical description

Monkeys range in size from the Pygmy Marmoset, at 140 to 160 millimetres (56 in) long (plus tail) and 120 to 140 grams (45 oz) in weight, to the male Mandrill, almost 1 metre (3.3 ft) long and weighing 35 kilograms (77 lb). Some are arboreal (living in trees) while others live on the savanna; diets differ among the various species but may contain any of the following: fruit, leaves, seeds, nuts, flowers, eggs and small animals (including insects and spiders). Some characteristics are shared among the groups; most New World monkeys have prehensile tails while Old World monkeys have non-prehensile tails or no visible tail at all. Some have trichromatic color vision like that of humans, others are dichromats or monochromats. Although both the New and Old World monkeys, like the apes, have forward-facing eyes, the faces of Old World and New World monkeys look very different, though again, each group shares some features such as the types of noses, cheeks and rumps. The pygmy marmoset or dwarf monkey (Cebuella pygmaea) is a quadrupedal New World monkey native to the rainforest understories of western Brazil, southeastern Colombia, eastern Ecuador, eastern Peru, and northern Bolivia, with an altitudinal range of 200 to 940 m. It is most common in river edge forests, but also can be found in secondary forest and moderately disturbed forest. The pygmy marmoset has been viewed as somewhat different from typical marmosets, most of which are classified in the genera Callithrix and Mico, and thus is accorded its own enus, Cebuella within the family Callitrichidae. Pygmy marmosets live 11-12 years in the wild, but in zoos, they live into their early twenties. There has been debate among primatologists concerning the proper genus in which to place the pygmy marmoset. An examination of the interstitial retinol binding protein nuclear gene (IRBP) in three marmoset species showed that Callithrix as constructed in the 1990's also needed to include C. pygmaea to be monophyletic, and that the times of separation of pygmaea and the argentata and jacchus species groups from one another are less than 5 million years ago, as might be expected for species of the same genus. However, subsequent separation of the argentata and jacchus species groups into different genera (the argentata group having been moved to Mico) justifies maintaining a separate genus for the pygmy marmoset, as Callithrix is no longer paraphyletic. There are two subspecies of the pygmy marmoset: Cebuella pygmaea pygmaea Western pygmy marmoset Cebuella pygmaea niveiventris Eastern pygmy marmoset It is one of the smallest primates, and the smallest true monkey, with its body length ranging from 14 to 16 centimetres (5.5 to 6.3 in) (excluding the 15-to-20-centimetre (5.9 to 7.9 in) tail). Males weigh around 140 grams (4.9 oz), and females only 120 grams (4.2 oz). Nicknames for this monkey often refer to its diminutiveness, for example: mono de bolsillo ("pocket monkey"), leoncito ("little lion"). The pygmy marmoset walks on all four limbs.