A young bear born to parents rescued from a Spanish circus will today undergo pioneering brain surgery.
Boki, a two-year-old European brown bear, has been suffering seizures and vision problems for the last five months.
MRI scans show he has hydrocephalus, a build up of fluid inside his skull that is putting pressure on his brain.
It's a condition that also occurs in humans, affecting one in every 500 births. Other cases can be triggered by illness or injury later in life.
But it is believed to be rare in animals.
Specialist vets working with the Wildwood Trust, near Canterbury, where Boki lives, will insert a tube in his brain to drain the fluid and relieve the pressure.
Mark Habben, zoological director at the trust, told Sky News that Boki was "charismatic and a lot of fun" but his condition tends to flare up after bouts of high energy.
"It impedes his life," he said.
"We want him to be able to climb up trees and jump in ponds without suffering negatively from that."
The three-hour operation will be carried out by Romain Pizzi, an Edinburgh-based specialist with a reputation for taking on cases that other vets won't touch.
He will make a small hole in Boki's skull and run a tube from inside his brain, then under his skin down to his bladder, where it will drain the excess fluid.
The vet has carried out the procedure just once before, on an Asiatic black bear in Laos. The surgery was a success, giving the Wildwood Trust confidence it's the right option for Boki.
Mr Habben said Boki is also in good physical condition and rapidly putting on weight.
"If we did not think this would have a happy ending, we would not put him or ourselves through the physical and emotional stress of conducting something like this," he said.
"We are very optimistic about it."
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Boki was born at Port Lympne wildlife park in Kent, where his parents were brought after being rescued. But he was aggressively rejected by his family and was moved to the Wildwood Trust.
The decision to go ahead with surgery was given extra urgency by Boki's imminent torpor, a winter dormancy similar to hibernation.
"Doing it now is the right thing to do because it's much easier to monitor him," said Mr Habben.
"If there is any medication or aftercare he needs, I don't want him to be asleep for four months to administer that.
"As he recovers from surgery we will be assessing him on a day-to-day basis to see when he can resume normal life of being a young bear again."