Hektoen International

A Journal of Medical Humanities

All too human: The mountain gorillas of Uganda

James L. Franklin
Chicago, Illinois, United States

Fig 1. Adult female mountain gorilla

The Ugandan mountain gorilla is a member of the Hominidae family, also known as the great Apes. The extant species include: the orangutan, the eastern and western gorilla, the chimpanzee, the bonobo, and ourselves—Homo sapiens. The mountain gorilla is one of two subspecies of the eastern gorilla. The one is found in the Virunga volcanic mountains of Central Africa, the other in Uganda’s Bwindi Impenetrable National Park.

It is estimated that the group of primates destined to evolve into gorillas split from their common ancestor with humans and chimpanzees about nine million years ago. Sitting quietly in the presence of a family of mountain gorillas, observing and being observed, it would seem that the separation occurred almost yesterday. The mountain gorillas have been isolated from the eastern lowland gorillas of the Congo for about 400,000 years. As an adaptation to the colder temperatures in the mountains, the fur of the mountain gorilla is thicker and longer than that of other gorilla subspecies. Males have a mean weight of 195 kg (430 lb.) and a standing height of 150 cm (59 in.). The adult males weigh twice as much as adult females at a mean of 100 kg (220 lb.) and a height of 130 cm (51 in.). Mountain gorillas are primarily herbivores; adult males will consume up to thirty-four kilograms of vegetation a day and females will eat as much as eighteen kilograms. Adult males are called silverbacks because of a saddle of silver-colored hair that develops on their backs with age.

The gorilla families are usually composed of one silverback and several females. About one third of groups will contain more than one male. The subordinate male may be a brother, half-brother, or son of the dominant silverback. In addition to the silverback the group may consist of three to four sexually mature females and three to six juveniles or infants. The silverback leads and defends the group, making decisions as to where they move and leading them to feeding sites. The groups spend most of the day foraging except for periods of rest in the midday. They construct nests of available vegetation each night to sleep.

These photographs were taken in early May 2018 in the Bwindi Impenetrable National Park located at the southwestern tip of Uganda. The park is part of the Bwindi Impenetrable Forest which is situated along the border with the Democratic Republic of the Congo. It is composed of 321 square kilometers of montane and lowland forest and is only accessible by foot. The park is inhabited by about 600 mountain gorillas that make up half of the mountain gorillas in the world. The other half live in the adjacent Virunga Mountains. Gorilla tracking is the park’s main attraction. Permits are required in advance and limited in number. Only small groups are allowed to view selected gorilla families that have been habituated to human presence. Park rangers familiar with the gorillas in the park go out early each morning to scout out the location of the gorilla families. The small groups, generally seven visitors, that visit the gorillas gather early in the morning to receive a briefing on proper etiquette during the visit. Visitors must be free themselves of any potentially contagious respiratory illness that might be transmitted to the gorillas. Visits are limited to only one hour once the gorillas have been reached. The gorillas in these photographs required both an arduous climb of about 2,000 feet and about a two-hour trek.

Fig 2. External ear of an adult
Fig 3. Left hand of a juvenile gorilla
Fig 4. A somewhat shy infant
Fig 5. His older brother
Fig 6. A silverback enjoying some fresh vegetation
Fig 7. View of local village from the mountain home of the gorilla family

JAMES L. FRANKLIN, MD, is a gastroenterologist and associate professor emeritus at Rush University Medical Center. He also serves on the editorial board of Hektoen International and as the president of Hektoen’s Society of Medical History & Humanities. He has traveled extensively in Africa and Asia.

Spring 2020 



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