Pygmy Marmoset

Monkey

The pygmy marmoset or dwarf monkey is a New World monkey native to the rainforest canopies of western Brazil, southeastern Colombia, eastern Ecuador, eastern Peru, and northern Bolivia. 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).

http://en.wikipedia.org/wiki/Pygmy_marmoset