In 1981, wildlife biologist Diane Fossey estimated the total mountain gorilla population at approximately 242 individuals. The species was in freefall — poaching for the bushmeat and trophy market, habitat destruction from agricultural encroachment, and the instability of the political environments surrounding the Virunga range had reduced one of the most distinctive primate species on earth to a population smaller than most suburban high schools. Conservation scientists studying the animals were preparing, with some grimness, for the possibility that they were documenting the last years of the species in the wild.
Today, the mountain gorilla population stands at over 1,000 individuals — the only great ape species whose population is increasing rather than declining. This recovery represents one of conservation’s most significant achievements, accomplished through a combination of sustained field research, anti-poaching operations, community engagement, veterinary intervention, and — critically — the development of a viable gorilla tourism model that turned the animals from a poaching target into a conservation asset. Understanding how this happened provides essential context for every gorilla trekking visitor who stands in Bwindi’s forest and wonders how different the story could have been.
The species and its restricted range
Mountain gorillas (Gorilla beringei beringei) are a subspecies of the eastern gorilla, found in only two locations on earth: the Virunga Massif — the chain of extinct and dormant volcanoes straddling the borders of Uganda, Rwanda, and the Democratic Republic of Congo — and the Bwindi Impenetrable Forest in southwestern Uganda. These two populations are geographically separated and are considered genetically distinct, though the degree of differentiation is a matter of ongoing research discussion.
The restriction of the species to these two isolated forest fragments is a consequence of habitat loss over the past two centuries. Mountain gorillas once had a wider range across the highland forests of the Albertine Rift, but agricultural expansion from the nineteenth century onward reduced that range to its current extent. Today the gorillas are literally surrounded by one of the most densely populated rural landscapes in Africa; the protected areas they inhabit are forest islands in a sea of human settlement and cultivation.
The role of Dian Fossey
The name most associated with mountain gorilla conservation internationally is Dian Fossey, the American zoologist who established the Karisoke Research Center in Rwanda’s Virunga Mountains in 1967 and spent the following eighteen years studying the animals and campaigning against poaching. Fossey was a complex, controversial figure — her methods in dealing with poachers were often aggressive and her relationships with local communities frequently difficult — but her scientific contributions were foundational and her ability to bring global attention to the species’ plight was unmatched.
Fossey’s habituated gorilla groups — particularly the family she called Group 4 and the silverback she named Digit, whose killing by poachers in 1977 sparked international outrage — became the basis for public awareness campaigns that raised both funds and political pressure. Her 1983 book Gorillas in the Mist and the 1988 film adaptation brought the mountain gorilla’s situation to audiences globally. Fossey’s murder at Karisoke in December 1985 — almost certainly at the hands of people connected to the poaching networks she had been fighting — drew further attention and resources to mountain gorilla conservation.
The Dian Fossey Gorilla Fund International, established after her death, continues to operate the Karisoke Research Center and maintains the longest continuous primate study in history. The data accumulated over more than fifty years of daily observation of Virunga gorilla families constitutes one of the richest longitudinal datasets in field biology and continues to generate research publications that advance understanding of gorilla ecology, behaviour, and health.
The development of gorilla tourism
The most transformative conservation innovation for mountain gorillas was the development of controlled tourism as a revenue model for conservation. Before tourism was established, gorillas had value only as trophies or bushmeat — economic incentives that pointed entirely toward exploitation. The challenge was creating a system that made living gorillas more economically valuable than dead ones to the communities and governments that made conservation decisions.
Rwanda pioneered mountain gorilla tourism in the 1970s and 1980s under the Mountain Gorilla Project, a collaborative initiative between the African Wildlife Foundation, the World Wildlife Fund, and Fauna and Flora International. The project habituated specific gorilla families to close human presence through a carefully managed process, then began accepting small groups of tourists for daily visits. The revenue generated — initially modest but growing rapidly through the 1980s — demonstrated that gorilla tourism could generate enough income to fund conservation operations while also contributing to national park budgets and community benefit programmes.
Uganda developed its own gorilla tourism programme after Bwindi was gazetted as a national park in 1991. The first gorilla trekking permits were sold at Buhoma in 1993, with the Mubare Group becoming Uganda’s first habituated gorilla family accessible to tourists. The programme expanded gradually over the following decades as additional groups were habituated and the visitor capacity increased to its current level across four sectors and multiple habituated families.
Population growth: the numbers behind the recovery
The mountain gorilla census is conducted approximately every five to ten years using a combination of nest counts, direct observation, and genetic sampling. The results tell a story of remarkable recovery:
1981: approximately 242 individuals (Fossey’s estimate). 1989: approximately 320 individuals in the Virunga population. 2003: approximately 380 individuals across both populations combined. 2008: 786 individuals in a combined census — the first time the population was comprehensively counted across both Virunga and Bwindi populations simultaneously. 2010: 480 individuals in the Virungas alone. 2018: 604 individuals in the Virunga population and an estimated 459 in Bwindi, for a combined total exceeding 1,000 — the milestone that prompted reclassification from Critically Endangered to Endangered on the IUCN Red List, a conservation milestone celebrated globally.
The growth rate has been approximately 3 to 4 percent per year in recent decades — unusually high for a large-bodied primate with low reproductive rates. The growth reflects both reduced poaching mortality and improvements in health management through veterinary intervention in the habituated populations.
Veterinary medicine and gorilla health
The Mountain Gorilla Veterinary Project (MGVP), now operating as Gorilla Doctors, provides veterinary care to habituated gorilla populations in Uganda, Rwanda, and DRC. The programme intervenes when habituated gorillas are observed with snare injuries, respiratory infections, or other health conditions that can be treated to improve survival outcomes. Since its founding in 1986, Gorilla Doctors has documented over 200 interventions — operations to remove snares, treatment of respiratory infections, and management of traumatic injuries — that have directly saved animals that would otherwise have died.
The population-level impact of veterinary intervention is significant. In a population of 1,000 animals with an annual growth rate of 3 to 4 percent, saving even a small number of individuals per year contributes meaningfully to the long-term trajectory. More importantly, veterinary monitoring of habituated groups provides early warning of disease events that could affect multiple individuals — the COVID-19 pandemic prompted immediate implementation of enhanced health protocols for gorilla tourism, including mandatory mask use and increased minimum distances, that have protected the animals from potential human disease transmission.
What the recovery means and what remains fragile
The 2018 reclassification from Critically Endangered to Endangered was a genuine conservation milestone but was accompanied by consistent messaging from conservationists that the species remains precarious. A population of 1,000 individuals confined to two small forest fragments surrounded by dense human settlement has no buffer against disease outbreaks, political instability, or climate-driven habitat change. The DRC component of the Virunga population lives in an area of persistent armed conflict that has disrupted conservation operations multiple times and has led to the deaths of park rangers protecting the gorillas.
The mountain gorilla’s continued survival is directly dependent on the continuation of the conditions that produced the recovery: funded park management, anti-poaching enforcement, maintained habituation programmes, veterinary support, community benefit programmes that maintain local support for conservation, and tourism revenue that funds all of the above. The visitor standing in Bwindi’s forest is not a passive observer of a conservation success — they are an active participant in the ongoing funding mechanism that makes the success continue. That is worth knowing, and worth remembering.
