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). Despite its name, the pygmy marmoset is somewhat different from the typical marmosets, most of which are classified in the genera Callithrix and Mico; as such, it is accorded its own genus, Cebuella.
Pygmy marmosets live 11-12 years in the wild, but in zoos, they live into their early twenties. Marmosets often live in groups made up of an adult pair and its offspring; ranging from 2-6 members. Young marmosets typically remain in the group until after 2 consecutive birth cycles.