The grivet (Chlorocebus aethiops) , also known as African green monkey and savanah monkey is an Old World monkey with long white tufts of hair along the sides of the face. Some authorities consider this and all of the members of the genus Chlorocebus to be a single species, Cercopithecus aethiops. As here defined, the grivet is restricted to Ethiopia, Sudan, Djibouti and Eritrea. In the southern part of its range, it comes into contact with the closely related vervet monkey (C.