Do male gorillas have silver backs?

The silverback gorilla is a mature male of the species, and it will be some 11 or 12 years old. Consider that as people age, their hair goes grey or silver. The same applies to the old male gorilla. It's that simple. The silverback is not a separate species or an animal that has mutated. For instance, a lowland gorilla is a lowland gorilla, whether it is a 2-year old female or a 13-year old silverback male at the head of the family.
Adult Gorillas are known as silver backs due to the silver hair they develop when they reach adult hood