The Pygmy Marmoset (Cebuella pygmaea) is a monkey native to the rainforest canopies of western Brazil, southeastern Colombia, eastern Ecuador, and eastern Peru. It is the world's smallest monkey, with males reaching only 140 g (5 ounces), and females only 120 g (4.2 ounces).

Pygmy Marmosets have a tawny coat, and ringed tails that are as long as their bodies. They are omnivorous, feeding on fruit, leaves, insects, and sometimes even small reptiles. Much of their diet, however, comes from tapping trees for sap. Up to two-thirds of their time is spent gouging tree bark to reach the gummy sap.