A Gorilla is a herbivore primate mammal that is commonly found in Africa. The Silverback is a Gorilla that has grown to adult size and has grown silver colored hair.
While interviewing Baron Dumas, Cate Archer had doubts that the ferocious "man eating" Silverback Gorillas of Pakistan actually existed. The Baron insisted that they were real and that he had faced off against one of them while on one of his hunting expeditions.
Gorilla on Wikipedia