In 2009 the Nshongi group was the largest habituated gorilla family in Uganda, numbering thirty-six individuals under the leadership of a dominant silverback named Nshongi. By 2015 it had undergone fission — splitting into multiple sub-groups — and the group that retained the original name numbered eleven individuals. What happened over the five years following that split, as the reconstituted Nshongi group rebuilt its numbers to twenty-five, is a story of gorilla resilience, reproductive success, and the complex social dynamics that govern how mountain gorilla families grow.
Why Large Groups Split
Gorilla group fission is a natural process that occurs when groups become too large for their social structure to manage effectively. The primary driver is competition between silverbacks — as blackbacks mature into silverbacks, the existing dominant male may tolerate some as subordinates, but tension over reproductive access to females and social precedence eventually creates conditions for departure. In the Nshongi group’s case, the fission produced three separate groups: the Mishaya group (led by the departing blackback Mishaya), the Bweza group, and a reconstituted Nshongi group under a new dominant male.
The reconstituted Nshongi group in 2015 comprised eleven individuals: the dominant silverback, three adult females, three juveniles, two infants, and one blackback. For gorilla researchers monitoring population dynamics, this presented a natural study in post-fission recovery — how quickly could a smaller group rebuild to a viable social unit?
The Reproductive Rate
Mountain gorillas have a slow reproductive rate by primate standards. Females give birth approximately every four years, and infants require several years of intensive maternal care before they achieve independence. Given this pace, growing from eleven to twenty-five members in five years requires sustained reproductive success across multiple females simultaneously — a combination of the dominant silverback’s fertility, the health of the group’s females, and the survival of infants through their vulnerable early years.
Between 2015 and 2020 the Nshongi group recorded fourteen surviving births. Three infants did not survive their first year — a loss rate that, while painful, is within the range of natural infant mortality for habituated gorilla groups. The eleven survivors, combined with the group’s existing juveniles growing to adulthood, produced the population increase that researchers documented.
The Role of Veterinary Support
Gorilla Doctors, the veterinary organisation that provides medical care to habituated mountain gorilla groups in Uganda, Rwanda, and the Democratic Republic of Congo, intervened in at least two cases during this period where infant survival was at risk. In one case a newborn was found with a respiratory infection that, untreated, would likely have been fatal. The Gorilla Doctors team monitored the infant remotely and, when the infection progressed, conducted a cautious intervention that allowed treatment without full anaesthesia. The infant survived.
This kind of intervention is possible only for habituated groups — gorillas accustomed to human presence will tolerate closer proximity from familiar veterinary teams than unhabituated gorillas would. The habituation that allows gorilla trekking tourism also enables the veterinary access that supports group health and survival.
What Trekkers See Today
The Nshongi group in 2027 is a thriving, stable family of approximately twenty-five individuals, receiving trekking visitors at Rushaga sector in Bwindi’s south. Trekkers who visit the group are walking into the result of five years of reproductive success, veterinary support, anti-poaching protection, and the complex social management of a growing gorilla family. The gorilla permit costs $800 per person. The Nshongi group’s current size is a direct consequence of the conservation model that permit supports.
