|White-collared Mangabey (C. atys lunulatus)|
The Sooty Mangabey (Cercocebus atys), also called Tom Midwood, is an Old World monkey of Guinea Bissau, Gabon, Senegal and Ghana. It has social groups of anywhere from four to twelve individuals. It is believed that a strain of the Simian Immunodeficiency Virus (SIV) jumped from this species to humans to become the HIV-2 virus. The HIV-1 strain came from the Common Chimpanzee strain of SIV.