Marmosets are native to South America. Compared to other monkeys, they show some apparently primitive features: they have claws rather than nails and tactile hairs on their wrists. They lack wisdom teeth, and their brain layout seems to be relatively primitive.
Marmosets are highly active, living in the upper canopy of forest trees, and feeding on insects, fruit and leaves. They have long lower teeth which allow them to chew holes in tree trunks and branches to harvest the gum inside; some species are specialised feeders on gum.
Marmosets live in family groups of three to 15, consisting of one to two breeding females, an unrelated male, their offspring and occasionally extended family members and unrelated individuals.