Gorillas

Mountain gorillas inhabit the highlands of Uganda, Rwanda and DR Congo. They evolved half a million years ago, with the rise of the Virunga volcanoes, adapting to the terrain by diverging from other eastern gorillas, becoming bulkier and hairier.

They are herbivores who sometimes eat ants and termites. They tend to eat in the morning and in the afternoon and travel 1-2km (1mi) in search of suitable nesting sites.

Mountain gorillas use vocalisations, physical gestures and movement to communicate. Their contact grunts are very important for group cohesion and coordination.

Females reach sexual maturity at eight years and mate with some or all males in the group. Pregnancy is 8.5 months and there are 3-4 years between births. At birth they weigh 1.5-2kg (4lb) and after four months ride on their mother’s back.

A silverback is an adult male, over 12 years old, with a distinctive patch of silver hair on his back and large canine teeth. He is the group leader, makes all the decisions, mediates conflicts, leads them to feeding sites and is responsible for defence, safety and well-being.

Discovered in 1902, their groups consist of 10-20 members and they live 30-50 years. There are only about 1,000 mountain gorillas in existence but their number is increasing. They can be visited in four parks: Rwanda’s Volcanoes NP, Uganda’s Bwindi and Mgahinga NPs and Congo’s Virunga NP.

Grauer’s gorillas • photo by Marcus Westberg

Kahuzi-Biega NP is the only place in the world where habituated Eastern lowland gorillas (also known as Grauer’s gorillas) can be seen. The biggest of all gorilla subspecies, Grauer’s males grow to almost two metres (6 feet and 5 inches). They have shorter hair than mountain gorillas. It is estimated that there are about 3,500 of them left on the planet.

featured image: silberback mountain gorilla in Mgahinga Gorilla National Park by Jiro Ose

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