BWINDI, Uganda — Sept. 24 is observed as World Gorilla Day. It was launched in 2017 to coincide with the 50th anniversary of the establishment of a Rwanda-based gorilla study center founded by Dian Fossey, the American primatologist and conservationist who gained global renown for her research.
The gorillas Fossey studied and looked after were mountain gorillas that belong to the species known as the eastern gorilla and live mostly in the Virunga Massif, a mountainous area encompassing parts of Congo, Rwanda and Uganda. The second species, known as the western gorilla, inhabits areas of west and central Africa.
Gorillas are losing their habitat because of poaching and other threats. The International Union for Conservation of Nature lists both gorilla species as endangered, with three of four subspecies critically endangered.
Here are some things to know about the great apes:
Humans share much of their DNA with gorillas, and scientists cite figures showing up to 98% similarity. “Gorillas are humans’ closest living relatives after chimpanzees, and are of comparable importance for the study of human origins and evolution,” according to the science journal Nature. This kinship with humans is one reason gorillas are susceptible to infections spread through close contact with tourists, researchers and others who come near them. Gorillas are especially vulnerable to the influenza virus, and respiratory illnesses are a frequent cause of death among adult gorillas.
Visitors tracking gorillas in the wild are usually urged to stand at least 7 meters (yards) from the primates — as well as not to touch them even if they wander, as they sometimes do, closer to people. In her lifetime, Fossey worried that gorilla tourism was injurious to the well-being of gorillas because it might alter their behavior in the wild, but tourism-driven gorilla conservation projects in countries such as Uganda has proved successful over the years.
Gorillas in the wild live in families, with the dominant male — known as the silverback because of the patch of silvery fur on his back — as the head of the group. He can co-exist with younger males, who defer to him, as well as many females, juveniles and infants.
Uganda’s Bwindi Impenetrable National Park, home to many of the world’s remaining gorillas, has 27 families considered “habituated,” trained to appear comfortable in the presence of humans. Most silverbacks are known to be protective of their families. The silverback in one of the Bwindi families is named Murinzi, a local word for “protector,” because rangers have seen him to be quite solicitous.
To assert their authority, silverbacks sometimes stand on their hind legs, beat their chests and vocalize, sending younger males in flight and warning rivals from other groups. Gorilla mothers are just as generous with their offspring, and the “love they show for their youngsters is undeniably deep and evident to everyone lucky enough to observe it,” according to the Dian Fossey Gorilla Fund, a charity working to protect the primates. Gorillas can live for over 40 years in the wild.
The powerful majesty of gorillas in the wild is one reason they fascinate tourists. But while they are the largest living primates, they can also seem gentle and meek. An average silverback can weigh up to 180 kilograms (396 pounds). Herbivorous creatures, gorillas eat mostly leaves and the shoots and stems of plants. They may also eat ants and snails.
The International Gorilla Conservation Program says the main threat to gorillas is habitat loss from the clearance of the forested ecosystems they inhabit. “Conversion of land for agriculture and competition for limited natural resources such as firewood lead to varying degrees of deforestation,” according to the group, a coalition of conservation nonprofits focusing on the survival of mountain gorillas.
