Mr Collins advised veterinary surgeon Jane Hopper
A surgeon who spent more than 30 years operating on humans came out of retirement to help supervise surgery on a gorilla at a Kent zoo.
Endocrine surgeon Richard Collins helped remove two parathyroid glands from Tambabi, a 22-year-old female who had suffered severe weight loss.
Mr Collins said the neck operation was fairly common in humans but there was no record of any other gorilla patient.
Tambabi is one of a group of 71 gorillas at Howletts Wild Animal Park.
She was anaesthetised for two hours, with the surgery taking just over an hour.
Her operation was performed by resident veterinary surgeon Jane Hopper, with Mr Collins in the theatre to advise.
"I have performed numerous operations of this type but felt that it was a privilege to be asked to be present in an advisory capacity," said Mr Collins, who recently retired from the Kent and Canterbury Hospital.
He said the gorilla looked "rather undignified" on the operating table.
"They are not particularly tall but they are rather wide and powerful but once anaesthetised it was less of a challenge," he said.
"The neck looked not unlike a human neck though there were certain differences."
He said Tambabi was doing well.
"I fed her some bananas through the cage and she seemed extremely contented," he said.
"The operation didn't seem to bother her very much, but that was because of the way she was looked after.
"I am full of admiration for those who did it," he added.