When recently called in to help deliver a baby gorilla by caesarean, it wasn’t your average day for gynecologist and professor of reproductive medicine David Cahill. He’s delivered hundreds of babies, but this was the first time he’d ever been asked to deliver a gorilla, in what was the first C-section performed on a gorilla at Bristol Zoo in the U.K.

“Along with having my own children, this is probably one of the biggest achievements of my life and something I will certainly never forget,” says Professor Cahill. “I have since been back to visit Kera [the mother] and the baby gorilla, it was wonderful to see them both doing so well.”

Despite it being a little touch and go as the infant needed emergency resuscitation directly after the birth, the now 11-day-old western lowland gorilla is thriving and being looked after around the clock by dedicated staff at the zoo. When she was born on February 12, the as-yet-unnamed little girl weighed just over 1 kilogram (2 pounds 10 ounces). Her mother, Kera, was given a C-section after showing signs of a complication called pre-eclampsia, and is now recovering well.

“The birth of any gorilla is a rare and exciting event; but the birth of a baby gorilla by caesarean section is even more unusual,” explains the senior curator of animals at Bristol Zoo, John Partridge. “It wasn’t a decision that we took lightly – Kera was becoming quite poorly and we needed to act fast in order to give the best possible treatment to mother and baby, and to avoid the possibility of losing the baby.”

Western lowland gorillas (Gorilla gorilla gorilla) are native to central Africa. Although there are an estimated 95,000 of the apes roaming the forests, they are considered as “critically endangered” by the International Union for the Conservation of Nature. This is because their numbers are based on old estimates, and the apes are under intense pressure from habitat loss and hunting.

While the gorilla house at Bristol Zoo is still open so visitors can see its troop of eight gorillas, the baby is not yet on display to the public.

Main image credit: Brsitol Zoo/YouTube