Cara, a 33 year-old Chimpanzee at Wellington Zoo, has had an operation to resolve persistent ear problems.
Yesterday ear, nose and throat surgeon Dr Rebecca Garland conducted ear canal ablation surgery, which involves removing the entire ear canal at The Nest Te Khanga at the zoo.
Cara had been given a custom-made ear plug but problems persisted, prompting the decision to carry out the latest surgery.
"Surgery went smoothly, and we were able to patch up Cara's ear," said Dr Garland.
"As with humans, the resulting loss of hearing after having both ear canals removed will be approximately 60 percent."
However, a hearing test done while Cara was anaesthetised showed that her level of hearing had already been compromised.
Vets are confident she will integrate back into the troop of Chimpanzees.
"Chimpanzees communicate primarily through gestures, body postures and facial expressions, as well as some vocalisations," said Paul Horton, life science manager at Wellington Zoo.
"Cara's hearing has been impacted for some time without impacting her status among the other Chimpanzees.
"Knowing that she had already lost a significant level of hearing and had still functioned well within the group means we can be confident that she can be integrated back into the group without issue."