The fossil record provides evidence of the hominoid primates (apes) found in East Africa approximately 22–32 million years ago.

[14] The mountain gorilla is diurnal, spending most of the day eating, as large quantities of food are needed to sustain its massive bulk.

[18] The home range used by one group of gorillas during one year is influenced by availability of food sources and usually includes several vegetation zones.

It travels to the bamboo forest during the few months of the year when fresh shoots are available, and it climbs into subalpine regions to eat the soft centers of giant senecio trees.

[16] The mountain gorilla is primarily a herbivore; the majority of its diet is composed of the leaves, shoots, and stems (85.8%) of 142 plant species.

[20] The mountain gorilla is highly social, and lives in relatively stable, cohesive groups held together by long-term bonds between adult males and females.

[36] In October 1902, Captain Robert von Beringe (1865–1940) shot two large apes during an expedition to establish the boundaries of German East Africa.

Fossey made new observations, completed the first accurate census, and established active conservation practices, such as anti-poaching patrols.

[40][46] Habituation means that through repeated, neutral contact with humans, gorillas exhibit normal behavior when people are in proximity.

Habituated gorillas are more closely guarded by field staff and they receive veterinary treatment for snares, respiratory disease, and other life-threatening conditions.

[46] Nonetheless, researchers recommended that some gorillas remain unhabituated as a bet-hedging strategy against the risk of human pathogens being transmitted throughout the population.

[47] Conservation requires work at many levels, from local to international, and involves protection and law enforcement as well as research and education.

Dian Fossey broke down conservation efforts into the following three categories: Karisoke Research centre has: A collaborative management process has had some success in the Bwindi Impenetrable National Park.

They included agreements allowing the controlled harvesting of resources in the park, receipt of some revenue from tourism, and establishment of a trust fund partly for community development.

The director of the IGCP, Eugène Rutagarama, stated that "They got more rangers on better salaries, more radios, more patrol cars and better training in wildlife conservation.

[51] The funding for these types of improvements usually comes from tourism - in 2008, approximately 20,000 tourists visited gorilla populations in Rwanda, generating around $8 million in revenue for the parks.

Under Rwandan law, 10% of this revenue must be returned to the community, which represents around €10 million invested in building schools, roads and drinking water supplies.

[40] In addition to tourism, other measures for conservation of the sub-population can be taken such as ensuring connecting corridors between isolated areas to make movement between them easier and safer.

[56] The late 1960s saw the Virunga Conservation Area (VCA) of Rwanda's national park reduced by more than half of its original size to support the cultivation of Pyrethrum.

The abduction of infants generally involves the loss of at least one adult, as members of a group will fight to the death to protect their young.

With young gorillas worth from $1,000 to $5,000 on the black market, poachers seeking infant and juvenile specimens will kill and wound other members of the group in the process.

In this situation, a Malaysian Zoo received four wild-born infant gorillas from Nigeria at a cost of US$1.6 million using falsified export documents.

Groups subjected to regular visits from tourists and locals are at a continued risk of disease cross-transmission (Lilly et al., 2002) – this is in spite of attempts to enforce a rule that humans and gorillas be separated by a distance of seven metres at all times to prevent this.

[63] Indeed, according to some researchers, infectious diseases (predominantly respiratory) are responsible for approximately 20% of sudden deaths in mountain gorilla populations.

[64] With the implementation of a successful ecotourism program in which human-gorilla interaction was minimised, during the period of 1989–2000 four sub-populations in Rwanda experienced an increase of 76%.

[65] The risk of disease transmission is not limited to those of a human origin; pathogens from domestic animals and livestock through contaminated water are also a concern.

[67][68] Rwanda, Uganda, and the Democratic Republic of Congo have been politically unstable and beleaguered by war and civil unrest during the last decades.

Using simulation modeling, Byers et al. (2003) have suggested that times of war and unrest have negative impacts on the habitat and populations of mountain gorillas.

[69] Due to the increase in human encounters, both aggressive and passive, this has resulted in a rise in mortality rates and a decrease in reproductive success.

[70] Pressure from habitat destruction in the form of logging also increased as refugees fled the cities and cut down trees for wood.