When Jamie Peyton first examined the bears’ paws last month, she figured they might take six months to heal.
Peyton, a veterinarian at the University of California at Davis, had treated cats and dogs with burns before, and she knew these were severe. The two female black bears in her care had survived the Thomas wildfire that swept through Southern California in December, but both suffered third-degree burns that had caused their paw pads to slough off. They could hardly stand due to pain.
Instead of six months, the bears’ injuries healed in a matter of weeks — a quick recovery Peyton attributed to a treatment never before tried on human or animal burn victims in the United States: tilapia skin applied as bandages.
Using fish skin wasn’t Peyton’s first instinct when state wildlife authorities enlisted her help. They had found one bear huddling on Dec. 9 in a backyard aviary near the town of Ojai and the other two weeks later in a nearby wooded area. A third patient, a 5-month-old male mountain lion with burned paws, was discovered in the woods shortly before Christmas. Kirsten Macintyre, a spokeswoman for the California Department of Fish and Wildlife, said officials determined the three were candidates for rehabilitation, which meant transferring them to a state wildlife investigations lab near Sacramento. A vet there suggested calling on Peyton, chief of the Integrative Medicine Service at the UC Davis veterinary teaching hospital.
Peyton said she first tried the usual care: cleaning the burns, removing dead tissue and applying ointments. But she knew two very important steps — covering the burns and providing pain control — would be tricky with these unusual patients, which needed to stay a safe distance from people when not sedated.
There was no guarantee they’d gulp down pain pills hidden in their food, Peyton said. “And we couldn’t put on any type of bandage material they would eat,” because that might cause intestinal obstruction. Also, she said, “if a bandage comes off, you can’t really go into the cage to get it.”
A fast recovery was imperative, especially for the second bear. Peyton’s team had discovered the bear was pregnant during an ultrasound exam, and they feared the stress of giving birth in captivity would cause her to reject the cub.
Then, the veterinarian said, she remembered a news story she had read about scientists in Brazil successfully using sterilized tilapia skin on human burns. Like the pig and human tissues that have long been applied to burns, the fish skin is moist and transfers collagen, a protein that helps healing. But it’s cheaper and widely available, because it’s a byproduct of tilapia sold as food. The Brazilian researchers told Reuters last year that it hastened recovery in their patients and reduced the need for pain medication.
Tilapia skin had some additional selling points in Peyton’s mind: It could remain intact for several days, and no harm would come to the bears and cougar if they ate it.
“I thought this would be perfect,” she said. “The skins are really, really strong, and it’ll help with pain control.”
Peyton procured the skin from a local fish market, sterilized it and then sutured it onto the sedated animals’ paws. To keep the scaly bandages protected, her team wrapped the paws in two other edible substances: rice paper and corn husks.
“We wrap their feet like tamales,” she said. “They were known either as ‘tamale feet’ or ‘California bear roll feet.’”
The bears stood soon after waking from sedation, a sign of improvement. They also didn’t remove the skin until their next application 10 days later, which Peyton took to mean the bears understood the treatment helped them feel better. Not so for the mountain lion kitten, which would eat its fish skin after a couple days.
“Cats don’t like stuff on their feet,” Peyton said. Fortunately, the mountain lion’s burns were less severe and required tilapia only on one paw, she said. “Once he started feeling better, he was playing.”
So fast did the bears’ paws heal that wildlife officials decided they were ready for release in mid-January. A state biologist spent a few days hiking around Los Padres National Forest — in a spot not too far from where the bears were found, but that hadn’t been damaged by fire — in search of good denning spots, Macintyre said. After she identified two about five miles apart, a team from the wildlife agency built dens from logs, brush and branches. They constructed an extra spacious one for the pregnant bear, she said.
“We wanted to give her particularly Cadillac accommodations,” Macintyre said.
On Jan. 17, the bears were sedated and outfitted with their final strips of tilapia skin, as well as radio collars and ear tags. Wildlife officials drove them to their new homes, then placed them in their dens and set up trail cameras nearby. Macintyre said they’re hoping to see footage of a bear cub in the coming weeks.
The mountain lion, who in the wild would have stayed with his mother until he was about 18 months old, is too young to be released. He’ll go to a wildlife rescue center, Macintyre said.
Peyton, meanwhile, said she plans to experiment more with using tilapia skin to help the kind of animals she more typically sees — pets.
“You get inspired by your patients, and my goal was really to just help that first bear, and then of course the other ones came in,” she said. “I’ve just been really impressed by how much pain release they got, and the really marked improvement in healing time.”
An earlier version of this article said the UC-Davis team was the first to use fish skin on human or animal burns in the United States. Kerecis, an Icelandic company, makes codfish skin product that has been used to treat human burn victims in the United States.