Grauer’s Gorillas Successfully Reintroduced to the Wild
Categories: Success Stories, Gorilla Groups, Democratic Republic of the Congo, Mt. Tshiaberimu, Grauer's Gorilla
Mwasa (at the right) at the fence of the enclosure with the GRACE gorillas (© GRACE)
For the first time, Grauer’s gorillas from a sanctuary were successfully reintroduced to the wild. The gorillas, who had been rescued from illegal wildlife trade, grew up at the GRACE (Gorilla Rehabilitation and Conservation Education) Center in Kasuhgo in eastern Democratic Republic of the Congo. They were reintroduced to the wild in Virunga National Park, more precisely: on Mt. Tshiaberimu.
These gorillas will provide a critical genetic boost to a small and isolated population of 8 gorillas living on Mt. Tshiaberimu, increasing the number of gorillas living there to 12. This translocation is the culmination of a more than five-year rewilding process led by GRACE, Virunga National Park and local communities, with support from Gorilla Doctors and Re:wild.
The gorillas arrived between 2010 and 2016 at the GRACE sanctuary, where they lived in a 39-acre facility that allowed them to forage, socialize, climb and play as they would in the wild. To find the best candidates for the reintroduction, a team from GRACE Gorillas, Virunga National Park and Gorilla Doctors evaluated all the suitable individuals and then selected Mapendo, Ndjingala, Isangi and Lulingu to rewild based on their behaviour, reproductive health and overall health. The process followed the best practice guidelines developed by International Union for the Conservation of Nature (IUCN) for the reintroduction of great apes.
Virunga National Park built a special facility for the gorillas to live in on Mt. Tshiaberimu as they transitioned to the wild. The gorillas – Isangi, Lulingu, Mapendo and Ndjingala – were airlifted from the GRACE sanctuary to the park in October 2024. They settled into the new facility on Mt. Tshiaberimu quickly – eating and sleeping normally – and their health remained stable during the move.
The gorilla monitoring team initially expected the transition period to take anywhere between several months to several years. Since Mt. Tshiaberimu is at a much higher elevation than the GRACE sanctuary, they were unsure how much time the gorillas would need to adjust to living in a colder climate and eating a diet consisting only of plants that grow natively on Mt. Tshiaberimu, without supplemental nutrition.
In late November 2024, the wild silverback Mwasa began visiting the four females at the fence line of the gorilla rewilding facility. He returned to the facility for several days indicating his interest in the females by beating the ground, posturing and making vocalisations, all of which are normal behaviours for a silverback. The females displayed behaviours indicating that they were equally interested in him, including staying within his line of sight, responding to his calls, and even choosing to sleep outside their indoor enclosures to be nearer to him along the fence line.
After several days of close observation, the gorilla monitoring team felt that the best decision for the gorillas was to give them the opportunity to spend time together in the wild. On December 3, 2024 Isangi, Lulingu, Mapendo and Ndjingala voluntarily left the gorilla rewilding facility on Mt. Tshiaberimu and joined Mwasa.
All four females are exhibiting behaviours that have made the gorilla monitoring team cautiously optimistic that they are successfully acclimating to living in the wild. The gorillas have been foraging appropriately, they have improved their nest-building skills, their coats are thick and shiny, and they have large “browse bellies” (full bellies) which is a good indicator that they are healthy. Mwasa and the females have been spending much of their time together and the gorilla monitoring team has seen matings.
Approximately 400 people participated and engaged in discussions about rewilding the gorillas, more than 50 community members visited the GRACE sanctuary in Kasugho, while 20,000 people attended community-based conservation events. GRACE also trained six caregivers, including a local traditional leader, from communities around Mt. Tshiaberimu to join the gorilla monitoring team responsible for tracking the gorillas in the wild.
Summary of the joint press release of GRACE, the Virunga National Park, Gorilla Doctors, Re:wild, ICCN
Good and Sad News
In December 2024, Ndekesiri gave birth to an infant in the Katsavara group. Therefore, during December the total number of gorillas on Mt. Tshiaberimu rose to 12 individuals (from 7), since the four GRACE females and the newborn infant joined the small population.
Unfortunately, on 6 June 2025 their number was reduced to 11 because 23-year-old Mwengeshali died. The cause of her death is now being investigated. Her offspring Kavango is under the care of his/her father Mwasa, and we hope that the 3.5-year-old will survive.
More by Re:wild (joint press release)