Meet the world’s smallest monkey—the pygmy marmoset! A full-grown pygmy marmoset could easily sit in an adult human's hand, and it weighs about as much as a stick of butter. But there is nothing tiny about a pygmy marmoset's tail: it's longer than its body. The tail is not prehensile, but it helps the little monkey keep its balance as it gallops through the treetops.
Pygmy marmosets do a lot of climbing because tree sap is their favorite food. They cling to the side of a tree trunk and bite a hole in the bark. When the tree sap oozes out, they lap it up with their tongue. The sap also attracts insects that the marmosets eat, too.
These mini monkeys have a super-flexible neck and can turn their head backward to watch for predators. Look for them across the path from the tigers.