A male's hair will start to turn silver around age 11. The silver-back is the center of attention in the group, with the other gorillas congregating around him during periods of rest and play. Gestation is from eight to nine months, resulting in a baby weighing four to five pounds. A baby is dependent on its mother for three years while it learns to build nests and forage for food. The mother holds her infant until it is about four months old, after which it is able to ride on her back, clinging to her fur.
Females bear a single baby every four to five years.
Mountain gorillas eat large amounts of vegetation from more than 70 different plant species, including wild celery, gallium, vines, berries, bamboo, roots and bark. When the bamboo plant sprouts in June and November, bamboo shoots can make up to 90 percent of the gorilla's diet. Led by the silver-back, gorillas travel around a large range, foraging for food. Each night they build fresh grass nests. Each mountain gorilla is truly an individual.