The smallest monkey in the world is the Pygmy Marmoset who lives in the rainforested areas of South America; Brazil, Columbia, Ecuador and Peru. It is 14-16 centimeters long, not including its tail which is another 15 to 20 centimeters. They like to live in the top of the rainforest canopy, where they can catch otherwise untapped food resources. Their diet includes insects, fruit, leaves, small reptiles and tree sap. They get at the tree sap by gouging holes in the bark.

These little creatures leap around the trees using their agile limbs and claws. They live in groups of up to 15 animals with only one breeding pair that can have up to four litters. In the extended family line, both the males and females assist in raising the babies, who are completely dependent for the first two weeks.

They are not endangered, like many of their brethren because they are able to adapt to wide variety of changes in their world. The biggest threat they face is habitat destruction; despite their adaptability, if the species of insects and plants upon which they subsist, they will be in danger.