The Sooty mangabey (Cercocebus atys), also known as the White-crowned mangabey, White-naped mangabey and White-collared mangabey (leading to easy confusion with the Collared mangabey), is a species of Old World monkey found in forests from Senegal east to Ghana. While overall rated as Vulnerable, the eastern race lunulatus, it is considered Endangered by the IUCN.