Attacks by silverbacks are usually due to humans taking the wrong approach. Gorillas do not charge out of aggressiveness but because they haven't been shown the proper respect.
Starting at age thirteen, the males' backs are covered with silver hair, the source of their name.
Silverbacks are the strong, dominant troop leaders. Each typically leads a troop of 5 to 30 gorillas and is the center of the troop's attention, making all the decisions, mediating conflicts, determining the movements of the group, leading the others to feeding sites and taking responsibility for the safety and well-being of the troop.
Males will slowly begin to leave their original troop when they are about 11 years old, travelling alone or with a group of other males for 2–5 years before being able to attract females to form a new group and start breeding. While infant gorillas normally stay with their mother for 3–4 years, silverbacks will care for weaned young orphans.
Gorillas move about by knuckle-walking. Adult males range in height from 1.65 m to 1.75 m (5.4 to 5.7 feet), and in weight from 140 kg to 165 kg (305 to 360 pounds). Females are about half the weight of males.
Gorillas are primarily terrestrial (although they lived in trees back in their evolutionary past). Gorillas live in tropical rain forests (in the forest edges and clearings), wet lowland forests, swamps, and abandoned fields.
Gorillas knuckle-walk using both their legs and their long arms (putting
pressure on their knuckles, with the fingers rolled into the hand). Gorillas
rarely walk using only their legs. They can climb trees, but do not do
so very often. Gorillas cannot swim.