Callitrichinae

Callitrichinae is a subfamily of the New World monkeys (family Callitrichidae) that includes most of the small primates known as marmosets and tamarins. Genera commonly cited in this subfamily include Callithrix (true marmosets), Cebuella (pygmy marmoset), Saguinus (tamarins), and Leontopithecus (golden lion tamarins), as well as Mico. Members are among the smallest primates, typically weighing less than two kilograms. They share several distinctive traits, including claw-like nails instead of the flat nails typical of other primates, long incisor-like canines used to gouge tree bark, and a diet that often relies on tree gum and saps in addition to fruit and insects.

Callitrichinae are native to tropical and subtropical forests of Central and South America. They occur from the Atlantic Forest of Brazil to Amazonian lowlands and Andean foothill forests, occupying a range of habitats from humid lowland rainforest to mosaic woodland. They are generally arboreal and highly dependent on tall vegetation for foraging and refuge.

They live in small, social groups and are notable for cooperative breeding, in which non-breeding adults assist in caring for offspring. In many species, twins are common; alloparenting by siblings and unrelated group members is widespread. Group sizes vary from a few individuals to over a dozen; territories are defended, and vocalizations play a key role in social communication.

Many Callitrichinae species face habitat loss and fragmentation and are affected by the international pet trade. Several species, such as the golden lion tamarin (Leontopithecus rosalia), have benefited from targeted conservation programs, including reintroduction projects and habitat restoration, though others remain threatened or endangered.