The term 'mandrill, e.g.' is a crossword solution that can be filled in with the word 'BABOON, ' which has 6 letters. A mandrill is a species of Old World monkey that is closely related to baboons and is native to tropical rainforests in southern Cameroon, Gabon, Equatorial Guinea, and Congo. Mandrills are the world's largest species of monkey and are easily recognizable by their colorful faces and fur.