This photo is from Gorilla Pictures
Photo: Kabo, a western lowland gorilla pauses along a trail.

Kabo, a Western Lowland Gorilla

Photograph by Michael Nichols

Gorilla tribes are led by silverbacks, but some young males, called blackbacks, are allowed to stay. Young males leave around age 11, forming small bands with other blackbacks. There are often skirmishes, with the bachelors attempting to usurp the silverback's role.