The red-tailed monkey, black-cheeked white-nosed monkey, red-tailed guenon, redtail monkey, or Schmidt's guenon (Cercopithecus ascanius) is a species of primate in the Cercopithecidae family. It is found in Angola, Cameroon, Central African Republic, Democratic Republic of the Congo, Kenya, Rwanda, South Sudan, Tanzania, Uganda, Zambia, and possibly Burundi. The red-tailed monkey is usually black, red, or orange.