An infant gorilla that has been hand-reared here at Bristol Zoo Gardens now has a surrogate mum.
Western lowland gorilla Hasani, who was born in August last year, was cared for by keepers after his birth-mother, Kala, struggled to look after him.
It meant a six-strong team taking it in turns to be with him around the clock for seven months during which he needed feeding up to eight times a day.
Two months ago keepers re-introduced him to his mother hoping that she would be able to care for him.
Lynsey Bugg, Curator of Mammals, said: “We really wanted to get them back together and give Kala another chance to look after him. Once Hasani was sufficiently mobile and physically ready for it, we felt the time was right to try them together again.
“But despite Kala being very keen to begin with, over time she continued to show the worrying signs of not being able to cope. We really tried everything we could every day over several weeks but in the end we had to accept that it wasn’t working.”
After a week’s break, keepers turned to 16-year-old Kera to see if she could take on the role of surrogate mum.
Lynsey said the introductions began with Hasani and Kera limited to touching through an open partition that Hasani only was able to move through. Keepers stayed close by and on hand but were able to progress to giving them full access to each other after a few days.
Eventually they left the two of them together and watched on TV monitors from a different part of the gorilla house, ready to step in if things did not go well.
Lynsey said: “It is a question of using experience and judgement to decide how long to leave them.”
It is the first time Kera has looked after an infant. She had a daughter, Afia, five years ago by caesarean section because she had potentially life-threatening pre-eclampsia. But she was so ill that another gorilla, Romina, became a surrogate mum to Afia.
Lynsey, who is an advisor on surrogacy for the gorillas’ EAZA Ex-situ Programme (EEP), said: “Although Kera had no rearing experience, she is very intelligent and we have been able to nurture her behaviour.
“She has seen several other females rear their youngsters and so had a good foundation on which to build on. All the way through hand rearing, Kera was keen to spend time with Hasani and the two always seemed to get on very well.”
Hasani is now spending every day and night with Kera and making good progress.
Lynsey said: “This is a fantastic success. We have taken a young gorilla that would otherwise have died and turned him around and he is back with his fellow gorillas inside of a year. It is an amazing achievement.”
Hasani will remain close to his surrogate mother for the next three to four years, as he learns to become more independent.
Lynsey said she was now working on plans to introduce Hasani to the other western lowland gorillas.
At present he and Kera are in a separate area of the gorilla house and being let out onto the island at different times to the other gorillas, but introductions to Hasani’s dad, Jock, and mother Kala have begun and are going well. Other troop members will be introduced over time.
Lynsey said: “Hasani has been near the other gorillas every day and has heard their calls and sounds, so he is used to them.
“He is developing nicely; he’s very mobile and is eating well. He’s also starting to copy Kera in natural gorilla behaviours such as nest building and stripping bark and leaves from branches. He will grow up to be a fully-functioning gorilla thanks to the efforts of his dedicated keepers.”
Visitors can see Hasani with Kera as well as the rest of the gorillas including the youngest, five-month-old Juni, at the Zoo every day.
Our eight gorillas are important because they are part of an international breeding programme to help safeguard the future of western lowland gorillas, a Critically Endangered species.
Gorillas have long been an important part of Bristol Zoo Gardens and, as well as breeding them, conservationists from Bristol Zoological Society work to help protect them and their habitat.
The Society is involved in a western lowland gorilla conservation project in Monte Alén National Park, Equatorial Guinea, an area regarded by the International Union for Conservation of Nature (IUCN) as critically important for the survival of the species.
For more than 20 years Bristol Zoological Society has also supported a sanctuary in Cameroon which helps look after orphaned gorillas and chimpanzees.
Bristol Zoo Gardens and Wild Place Project are run by Bristol Zoological Society, which is a conservation and education charity and relies on the generous support of the public not only to fund its important work at both zoos, but also its vital education and community outreach programme.
In March last year, the Society launched the BZS Appeal to ensure the future of its work ‘saving wildlife together’, following the temporary closure of both its sites in the face of the COVID-19 pandemic.