white faced monkey(looks like buttock to me.)

The White-faced Saki (Pithecia pithecia), also known as the Guianan Saki and the Golden-faced Saki, is a species of saki monkey, a type of New World monkey, found in Brazil, French Guiana, Guyana, Suriname, and Venezuela. This monkey mostly feed on fruits, but also nuts, seeds, and insects.