The male is almost twice as big and more colourful than the female. He has long, whitish sideburns and a magnificent cape of long hairs which may reach the ground if he reaches a ripe old age. Geladas resemble the hamadryas baboon, with which they sometimes mix when their range overlap .
Males are more colourful and larger.
One young, sometimes twins. Mating usually in autumn with births in February to April. Females mature in 3-4 years, males in 8 years. This unit merge to form bands of 30-350, which may merge further during food abundant periods to reach 670. Only in Africa, in a limited region in northern and eastern Ethiopia.