The gelada is often referred to as the gelada baboon and the bleeding-heart baboon but is not a true baboon. These brown and grey primates are Old World monkeys that do bear some similarities to baboons. Twice the size of females, males are as big as a large dog and are equipped with vampiric canines, which they often bare at each other as a display of dominance or aggression. Both sexes have large, fluffy manes, as well as distinct, hourglass-shaped, bald patches of skin on their chests. They also have the most opposable index fingers and thumbs than any other primate.