The mountain gorilla is the most endangered of the three subspecies. There are no mountain gorillas in zoos today. Mountain gorillas live in social groups ranging from two to more than 35 individuals. 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.