Zoo vets’ innovative ear procedure foiled by Chimpanzee
Cara, a 33-year-old Chimpanzee who lives at Wellington Zoo, underwent a ground-breaking procedure under general
anaesthetic last Tuesday in a last-ditch effort to save her remaining ear, but further surgery will be required after
she found a way to foil the procedure.
Ear, nose and throat specialist surgeon Dr Rebecca Garland assisted Wellington Zoo’s veterinary team with a creative
solution to cure a persistent infection in Cara’s right ear – a custom-made plug to prevent the Chimpanzee inserting
sticks and pieces of straw in her ear.
The procedure went smoothly after several last-minute adjustments to the plug were made. However, Cara wasn’t a fan of
her new ear accessory – and the clever primate found a way to remove the plug shortly after waking up from general
“While we hoped for a good outcome, we knew it was possible that Cara or another member of the Chimpanzee troop would
succeed in removing the plug,” said Veterinary Sciences Manager Dr Lisa Argilla.
“This was our last shot to save Cara’s ear before resorting to ear canal ablation surgery which means removing the
entire ear canal, so it was absolutely worth trying. Cara has already undergone this life saving surgery on her left
ear, so unfortunately repeating this procedure on her remaining ear will mean that she may lose her hearing completely.
As losing her hearing completely may have an impact on Cara’s future in the group, another expert has been contacted to
come and assess her hearing during the next procedure. Dr Craig Johnson, Professor of Veterinary Neurophysiology at
Massey University will test Cara’s hearing while she is anaesthetised using a technique called Brainstem Auditory Evoked
Potentials. This will allow him to objectively evaluate Cara’s ability to hear.
Chimpanzees communicate through a system of vocalisations, gestures, body postures and facial expressions. Cara’s loss
of hearing may lead to changes for her in the Wellington Zoo Chimpanzee troop, which has a complex hierarchal system
that can change easily. Zoo Keepers will be keeping a close eye on how the group interacts when Cara returns.
“By testing Cara’s hearing before and after the surgery, we’ll be able to gain a better understanding of how to monitor
her interactions with the group after her surgery,” said Dr Argilla. “This also means we can get a good idea of her
hearing ability without having to do a separate procedure, which will mean Cara wouldn’t need to be anaesthetised
The date for Cara’s next surgery will be scheduled in the next four to six weeks, and Zoo visitors will be able to watch
first hand at The Nest Te Kōhanga as Zoo staff talk through each step of the operation.
The Nest Te Kōhanga is Wellington Zoo’s animal hospital, which provides specialist care for Zoo animals and native