This article is part of our series on South American animals.

We already know South America is a land of superlatives. Biggest rainforest, longest river, highest waterfall. But it’s also home to some extreme animals—including the world’s smallest monkey. And it’s pretty cute.

Pygmy marmosets grow to be only 6 inches long, up to 5 ounces, and fit comfortably in the palm of your hand. But don’t be fooled. These little balls of fuzz know how to survive in the Amazon. They can jump 15 feet in a single bound and their tales are longer than their bodies for increased stability. They’re found in the rainforests of Brazil, Colombia, Peru, Ecuador, and parts of northern Bolivia and prefer to live in the várzea (flooded forest). Pygmy marmosets are not endangered and visitors to the Amazon have a good chance of seeing them, especially around Iquitos then the river is high (February-May).

When seen in the wild, pygmy marmosets can be mistaken for squirrels from a distance. They scurry so quickly through the canopy and around tree trunks that the untrained eye will only recognize their distinctive lion-like mane when they’re sitting still. The fringe of orange tinted fur surrounding their inquisitive face is why some local names for the pygmy marmoset translate as “little lion.”

Though pygmy marmosets eat insects and fruit, their primary diet is tree sap. Unlike most primates, the pygmy marmoset has clawed fingernails that help it cling to trees, likely because their hands are too small to wrap around branches. This is essential for sap sucking. These tiny monkey run up and down tree trunks head first looking for the perfect spot to sink their teeth through the bark. Their feeding habits make it fairly easy to identify if you’re in the territory of a group of pygmy marmosets: the trees will be covered in bulbous sap wounds. You could also listen. Pygmy marmosets live in groups of 6-9 individuals and communicate with a high-pitched chatter.

If you think adult pygmy marmosets are adorable, wait until you see a baby. Newborns are only half an ounce at birth, about the size of a person’s thumb. Females give birth about twice a year, and almost always to twins. Unfortunately, their appeal has made them a victim of illegal pet trade. Though monkeys are commonly sold in Amazonian markets, it’s fairly difficult—and illegal—to take them out of the country.

Thanks to Missud for the title image of this blog.