Updated
Mountain gorillas usually live about 35–40 years in the wild, and a few reach their 40s. Many die much younger: infancy is the most dangerous period, with deaths from disease, accidents, infanticide when a new silverback takes over, and, in the past, snares and poaching. There are no mountain gorillas in zoos, so all lifespan data comes from decades of monitoring wild groups in the Virunga volcanoes and Bwindi. Western lowland gorillas in zoos often live into their 40s or 50s, which is why figures you see online vary.
The stages of a gorilla’s life
A gorilla is born after a pregnancy of about eight and a half months, weighing roughly 2 kg, and rides on its mother for the first months. Infants nurse for around three years and stay close to their mothers until four or five.
Females usually give birth for the first time at around ten years old, and then about every four years, so a female may raise only a handful of offspring in her lifetime. Males become blackbacks in their early teens and develop the silver saddle of an adult silverback at around 12–15 years, then may leave their group, live alone or with other males, and try to form or take over a family.
Why many gorillas die young
The first few years carry the highest risk. Infants can die from respiratory infections, some caught from humans, from falls and injuries, and from infanticide, which can happen when a new silverback takes over a group or groups clash. Adults face injuries from fights between silverbacks, disease, and, especially in the past, wire snares set for antelope, which can cause fatal wounds. Better protection, veterinary care for snare injuries and strict health rules for visitors have reduced some of these risks, and the population has grown as a result.
Silverbacks and old age
Dominant silverbacks lead their families for anything from a few years to two decades. In Rwanda, Cantsbee led the Pablo group for more than 20 years and lived to about 38, among the longest-lived and best-known silverbacks studied. As silverbacks age, younger males in the group may challenge them, and leadership can pass peacefully or after fights; see our guide to gorilla social behaviour. Some lives end violently: Rafiki, the silverback of Bwindi’s Nkuringo group, was killed by a poacher in 2020 at about 25 years old.
How scientists know
Researchers have followed mountain gorillas almost daily since Dian Fossey’s work at Karisoke in Rwanda began in 1967, recording births, deaths and family changes over generations. Habituated groups in Bwindi are also monitored every day by trackers and researchers, including the Institute of Tropical Forest Conservation at Ruhija. Because births and deaths are known for many individuals, lifespans are recorded directly rather than estimated. Read about research in gorilla conservation.
Why lifespan matters for conservation
Because females breed slowly, each death, especially of a breeding female or infant, has a big effect on population growth. That is why disease rules for trekkers, such as staying 7 m away and not trekking when ill, matter so much. Thanks to protection and tourism revenue, mountain gorillas have increased to at least 1,063, and in 2018 the IUCN moved them from Critically Endangered to Endangered. See our guide to how tourism helped save mountain gorillas and the rules for trekkers.
Frequently asked questions
About 35–40 years in the wild, with some reaching their 40s.
No. All gorillas in zoos are lowland gorillas, which often live into their 40s or 50s in captivity.
Males develop the silver saddle at around 12–15 years old.
About every four years, starting at around ten years old.
