Gorillas once caught by wildlife traffickers are set free in historic reintroduction

CNN

29-05-2025

Last October, four female eastern lowland gorillas were airlifted from their home in Kasuhgo, the Democratic Republic of Congo (DRC), and released 40 miles (64 kilometers) northeast in Virunga National Park.
Less than a year later, they have all successfully integrated into a group of wild gorillas, in what is being hailed as the largest translocation of the subspecies ever. Conservationists hope that its success will not only prevent the local extinction of an isolated population, but provide essential knowledge needed to protect the critically endangered apes in the future.
The females – named Isangi, Lulingu, Mapendo and Ndjingala, and aged between 10 and 21 years old – were rescued from the illegal wildlife trade as babies and taken to the Gorilla Rehabilitation and Conservation Education Center (GRACE) where they were rehabilitated over a long period of time, learning to forage and socialize as they would in the wild. Deemed ready for release, last fall they were flown to Mount Tshiaberimu – or 'Mountain of the Spirits' – a 1,700-meter (5,577-foot) peak in the northern region of the national park, where they were kept in a fenced enclosure before being released into the wild.
The gorilla monitoring team, who expected the transition to take anywhere between several months to several years, were astounded when, in less than two months, they appeared ready to leave the enclosure.
'It happened much quicker than we all anticipated,' says Katie Fawcett, executive and science director for GRACE Gorillas, the NGO leading the rewilding process alongside Virunga National Park and local communities.
This was partly down to the allure of a handsome wild silverback called Mwasa, who approached the fence of the enclosure day after day, beating his arms on the ground and grunting to catch the females' attention. It worked: they responded to his calls and even chose to abandon their indoor dens to sleep closer to him along the fence line.
Watching on carefully, the monitoring team decided that it was the natural time to let the females join him. 'We really pride ourselves on every decision being gorilla led,' Fawcett tells CNN. 'After three days of attention directed at the magnificent Mwasa … the decision was made: 'let's go for it.' The fence was cut so they could come out.'
Since then, to the team's surprise and delight, the four females have quickly settled into life in the wild, adjusting to the colder climate on the mountain's steep hills and a new diet of bamboo shoots and other native plants.
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While rangers continue to monitor the gorillas' health, collecting non-invasive biological samples and conducting visual assessments, so far the gorillas have shown no clinical signs of stress – in fact, they are looking 'amazing,' says Fawcett, with thick, shiny coats and full bellies.
The biggest excitement came in the new year, when Mwasa was spotted mating with Ndjingala, a 16-year-old female, for the first time. Since then, the other three have also been seen mating with him, according to Fawcett. As gorillas have a similar gestation period to humans, the team are eagerly counting down the days to September, but she says they are cautiously optimistic: 'It's probably going to take some time as the female gorillas were on contraception while they were in the sanctuary at GRACE.'
A birth would be a huge ray of hope for the whole species. The eastern lowland gorilla, or Grauer's gorilla, is found in the lowland tropical rainforest of eastern DRC and is the largest of the four gorilla subspecies – all of which are endangered.
While there have been successful translocations of western lowland gorillas in the past, eastern gorilla releases have had a very poor survival rate, with individuals dying or disappearing within weeks of release, or being so young that they have been unable to survive without a lactating mother.
'What's different about this reintroduction project is not only that it is the largest and we're putting in four females into this group, but also that the decision was made early on not to just throw a baby back into the group, but to rehabilitate it over a long period of time and make sure the gorilla has the social skills and critical survival skills,' says Fawcett. '(We were) trying to mimic that natural behavior of having adult females join a wild group.'
The project was also intended to provide a critical genetic boost to the small and isolated population of eight gorillas living on Mount Tshiaberimu. Previous scientific modelling found this population to be non-viable, with some estimating that it would go extinct between 20 and 50 years, unless new females were introduced.
'The tiny gorilla population was doomed but could now be saved by this intervention,' Liz Williamson, a professor at the University of Stirling in the UK specializing in the conservation, ecology and behavior of gorillas, who was not part of the project, said in an email. She added that the situation facing Grauer's gorillas across eastern DRC is 'dire,' but the translocation could bring multiple conservation benefits.
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Emmanuel de Merode, director of Virunga National Park and a Belgian prince, commended the initiative in a press release: 'This is a huge milestone in efforts to bolster the eastern lowland gorilla population and we are delighted that the gorillas are successfully adapting to the wild.'
However, there are huge challenges working within Virunga National Park, which has been the center of armed conflict for decades. Over 200 rangers have been killed in the park since it was created in 1925, and the recent resurgence of the M23 rebel group has escalated matters, with attacks on rangers becoming increasingly common. Mount Tshiaberimu is located within the troubled region.
'Working in this area is not easy,' says Jackson Kabuyaya Mbeke, DRC director for GRACE Gorillas. 'The main thing strategically is to put the community in the middle of everything we do: we recruit caregivers, we recruit educators who are trained at GRACE … and they feel that responsibility of taking care of wildlife.'
Brought up in the area himself, he recalls when gorillas were widespread and as a child, he would listen to them calling or beating their chests. 'We grew up in the same habitat, sharing the same resource,' he says. 'Gorillas are our identity, our totem, they are an important source of pride in this area.'
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Yet, as human populations grow, pressures on gorilla habitat are inevitable, with forest being cleared for agriculture and firewood. During times of conflict, with communities in extreme need, these threats are heightened as some resort to hunting gorillas for their meat.
The reintroduction is a huge breakthrough, but it is only the start. 'The real key for gorilla conservation success in this region is forest protection,' says Fawcett. 'We're super excited by this result and how it can help to inform these critically endangered populations, but we need to stop populations reaching that point.'