Large and heavily built, with a rounded muzzle and a shortened nose bearing ridges above hollow cheeks. Distinguished from all other baboons by its nostrils, which open on the side of its nose rather than terminally. Male has long, heavy dark brown cape covering forequarters. Forearms, hands and feet are black. Tail is brown and tufted, shorter than body.
Chest has heart-shaped patch of red naked skin sometimes divided in two in males.
Hand has short fingers and an opposable thumb. Ischial callosities are well developed. Sexual dimorphism in size, weight, canine development and presence of mane in males. High mountains of central and northern Ethiopia. Habitat is treeless open rocky and grassy mountainous regions at the edge of cliffs.