Hasani the baby gorilla is celebrating his first birthday at Bristol Zoo Gardens.
The critically endangered gorilla was born at the zoo 12 months ago and his keepers say Hasani is now thriving after initially struggling.
The western lowland gorilla was born on 18 August 2020 and was cared for by the keepers after his birth-mother, Kala, struggled to look after him.
It meant a six person team had to take it in turns to be with him around the clock for seven months during which he needed feeding 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 at Bristol Zoo Gardens, 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. Hasani is now spending every day and night with Kera and is 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
Visitors can see Hasani with Kera as well as the rest of the gorillas including the youngest, five-month-old Juni, at Bristol Zoo Gardens every day.
The eight gorillas at Bristol Zoo Gardens are important because they are part of an international breeding programme to help safeguard the future of western lowland gorillas, a Critically Endangered species.