This six inch, 6 ounce creature is the world's smallest monkey. Pygmy marmosets are found only in the western Amazon's flodplain forests, where they keep to the middle and lower canopy levels to avoid birds of prey. During the day they feed on fruits, insects, leaves, and spiders.

Marmosets have also specialized in lapping tree sap. With their long lower incisors, they gnaw holes in the tree trunk to tap the sap, then drink it as it oozes out. They will return repeatedly to a tapped site to feed. They move easily around the tree trunks because, except for the first toe, which has a flat nail, all their digits end in curved claws- a feature unique to marmosets and closely related tamarins. At night pygmy marmosets retreat to tree holes.