Cacajao

Cacajao, commonly called the uakaris, is a genus of New World monkey in the subfamily Pitheciinae of the family Pitheciidae, order Primates, named by Lesson in 1840 with the type species Simia melanocephalus. The genus contains eight currently recognized species. Uakaris are distinguished by short tails, 15 to 18 centimeters long, relative to a 40 to 45 centimeter head-body length, long loose body hair, a bald head with minimal subcutaneous fat giving the face an almost skeletal appearance, projecting lower incisors like their close relatives the saki monkeys, and vivid red facial skin that females are believed to use in evaluating male mate quality and that reflects overall health. The four traditionally recognized species inhabit flooded and riparian forest of the northwestern Amazon basin across Brazil, Colombia, Peru and Venezuela, with populations distributed north and south of river systems including the Amazon, Japura, Negro and Marauia rivers.