For a long time the image most people had of a gorilla encounter included chest pounding, roaring, charging, and big, bared teeth. But researchers studying gorillas reveal a very different picture of mountain gorillas. The animals are peaceful, gentle, social, and mainly vegetarian creatures. The occasional ferocious-looking, impressive displays are generally from a male gorilla protecting his family group from a threat.

A typical group is led by the biggest and strongest mature male gorilla—often the guy doing any chest pounding or charging. He's called a silverback because the hair on a male's back turns from black to silvery gray as he matures. This happens when he is between 11 and 13 years old. A silverback's group normally includes a subadult male or two and a few females and their young. Mountain gorillas wander around a home range of up to 15 square miles (39 square kilometers).

Mountain gorillas spend much of their time eating. Their food includes a variety of plants, along with a few insects and worms. At night the animals make a nest to sleep in. Many lightweight gorillas nest in trees, making beds of bent branches. The heavier individuals may nest in grasses on the ground. Babies snuggle with their mothers for the night.

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Life for mountain gorillas isn't all peaceful. They are endangered, threatened by civil war in a small area of Africa where they live. Hunters kill them for food or trophies. Their forests are chopped down for farmland, fuel, and housing. But many dedicated scientists, park rangers, and other concerned people are working hard to protect mountain gorillas, their forests, and their way of life in the mountains.