A brown bear who underwent pioneering, life-saving brain surgery has made a “very encouraging” recovery after six weeks of rehabilitation.

Boki, who lives at Wildwood Trust, near Canterbury, had been suffering from seizures which were believed to be caused by hydrocephalus, which is fluid on the brain.

In a bid to save his life, the two-year-old became the first brown bear on record to have brain surgery.

He had been medicated with prednisolone to deal with the swelling and build-up of fluid, but zoo workers would have been unable to treat him once he went into semi-hibernation.

It was decided that brain surgery was the best option for Boki, who went under the knife for five hours on Wednesday, October 9.

World-leading veterinary surgeon Romain Pizzi, who waived his fee for the job, fitted a stent between Boki’s brain and abdomen to help him pass the excess fluid.

Mr Pizzi said the surgery “appears to have been successful in improving his condition” and Boki is at the stage where experts can try to wean him off his medication.

“Six weeks seems like such a short time when you think of how far Boki has come since the day of his surgery,” said Mark Habben, director of zoo operations at Wildwood Trust.

“For the team who have shown such unrivalled dedication, caring for him day and night, it’s probably felt a lot longer than 42 days.

“Timescales aside, we’re in awe of the progress he’s made and remain incredibly grateful to Romain and everyone who has helped us get Boki back to the charismatic, carefree bear we first met nearly two years ago – albeit a slightly heavier version.”

Boki has put on 20kg since the surgery, a positive step, and has been enjoying enrichment such as cardboard boxes covered in honey.

After six weeks of rehabilitation and recovery, the team say he is almost back to his normal self.

Pictures taken on Monday show the brown bear, with part of his head shaved, moving around his enclosure.

Mr Pizzi, who also performed brain surgery on a black bear in 2013, said: “It is so wonderful to see that just over a month after surgery Boki is doing so well.

“Not only did he rapidly recover after the operation, climbing and playing only a few days later, but so far it appears to have been successful in improving his condition as we wean him off his medications.

“It is lovely to see after everyone’s hard work, efforts and donations have got us this far.”

Jon Forde, head of bears at Wildwood, pointed to Boki’s “natural bear behaviour” as another positive sign.

“Little more than six weeks ago, one of our biggest concerns was that Boki would go into torpor and not survive the winter,” he said.

“It was one of the main reasons that the surgery was so vital – we would not have been able to give him the medication or care he needed once he had gone into semi-hibernation.

“Now we’re welcoming this positive step. It’s been an absolute privilege to oversee his recovery since his surgery and to watch him gain weight and prepare for this next phase – it (is) all very natural bear behaviour.”