Marmoset, a New World monkey. Marmosets are found in South and Central America. There are more than 20 species, some of which are also called tamarins. Marmosets range in length from 5 to 13 inches (13 to 33 cm), not including the tail, which is 7 to 18 inches (18 to 46 cm) long. Marmosets have squirrellike bodies, silky fur, and sharp teeth. All the digits except the large toe have claws rather than nails. Marmosets move about in treetops during the day, feeding on tree sap, insects, eggs, and fruit. They usually give birth to twins. Many species, such as Goeldi's marmoset and the golden lion marmoset, are endangered due to destruction of their habitats.

Marmosets, according to most taxonomists, make up the family Cebidae. Some taxonomists place Goeldi's marmoset, Callimico goeldii, in the family Callimiconidae. The golden lion marmoset is Leontopithecus rosalia.