Which Amazonian primate is the world’s smallest monkey?

The pygmy marmoset is the world’s smallest monkey and is native to the western Amazon Basin.

This tiny New World monkey belongs to the genus Cebuella. Adults commonly weigh around 100 grams, although exact body mass varies between individuals and subspecies. Its small size helps it move through fine branches and feed on tree exudates, including sap and gum, as well as insects and fruit.

Pygmy marmosets usually live in small family groups and communicate with high-pitched calls, scent marking, and visual signals. They are often seen clinging to tree trunks while gouging bark with specialized incisors to obtain plant exudates.

The species is sometimes confused with other marmosets, but ordinary marmosets are larger. It is also not the world’s smallest primate overall: that distinction belongs to a mouse lemur, which is found in Madagascar rather than the Amazon. The pygmy marmoset is specifically the smallest monkey.