https://www.konicaminolta.com/kids/endangered_animals/library/field/bald-uakari.html

The bald uakari is an threatened species located in the Amazon near Brazil and Peru. Its red face may intimidate you but it’s actually a sign of good health. It is also red because of the lack of skin pigment. The bald uakari live in the treetops during the rainy season due to flooding. When the ground dries, it comes back down to look for nuts and fruit.