"A Silverback gorilla is the mature, experienced male leader of a group of mountain gorillas in the wild. Named for the silver saddles across his back, the Silverback is responsible for the safety of his group. A group of gorillas, also called a “troop,” can contain from 5 to 30 gorillas. The Silverback decides where the troop travels, where it forages for food, where it will rest and where it will sleep at night."
-Info source: http://animals.pawnation.com/silverback-gorilla-information-1760.html