You are using an outdated browser.
Please upgrade your browser
and improve your visit to our site.
Skip Navigation

Scientists Saved a Bear With Fish Skin—And Stumbled on a Game-Changing Idea

The story of California's rescued bears isn't just heartwarming. It's the beginning of a new way to think about burn treatment.

California Department of Fish and Wildlife

Bears and fish don’t usually get along very well. But together, it’s starting to look like they could help solve a global public health crisis.

First, bear with the beginning of the story, which warmed the internet’s collective cold heart last week. On Monday, the California Department of Fish and Wildlife released pictures of two female black bears who made miraculous recoveries after their paws were badly burned in December by the Thomas fire, the largest wildfire in California’s history. Veterinarians initially thought the animals’ third-degree burns would take up to six months to heal—far too long to keep them in captivity, especially considering one of the bears was pregnant. Instead, both bears made near-full recoveries after only a few weeks, and were released into Los Padres National Forest. The pregnant bear will now get to give birth in the wild, instead of at the veterinary hospital.

That’s heartwarming on its own, but what really made this story viral—it was picked up by the Associated Press, The Washington Post, National Geographic, and The New York Post, among otherswas the unique treatment used. Veterinarians can’t use regular bandages on animals, because they’ll eat the inedible material. So Jamie Peyton, chief of the Integrative Medicine Service at UC Davis Veterinary Teaching Hospital, decided to try wrapping the bears’ paws in fish skin—tilapia skin, specifically. Tilapia skin contains a high amount of collagen, which has been said to speed the healing process and reduce pain. “We made little spring rolls with their feet,” Peyton told the AP.

Most stories focused on the bears’ immediate well-being. Are they going to be ok? (Hopefully. Their original habitat was destroyed by the wildfire, but scientists made sure there were supplies for den-building near their release point, and are monitoring the area.) How did the bears not eat the delicious fish skin around their paws? (The skins were dried and wrapped in corn husks or rice paper, so they no longer smelled like fish. Plus, the bandages were helping relieve the bears’ pain, and Peyton said the bears likely noticed that.) If their paws were wrapped in corn husks, were the wraps really like spring rolls, or more like tamales? (Both—Peyton said she referred to their paws “either as ‘tamale feet’ or ‘California bear roll feet.’”)

California Department of Fish and Wildlife

Less obvious in these viral stories, however, were the implications of this successful treatment for burn victims—both human and animal—in the future. The World Health Organization considers burns “a global public health problem” among humans, noting that approximately 180,000 people die every year from burn injuries. Most of those burns are treatable, occurring in low- and middle-income countries that don’t have access to sophisticated skin-grafting care. In addition, veterinarians are increasingly concerned about burn injuries to domestic and wild animals as climate change worsens wildfires. Tilapia is cheap, abundant, and bandages made from it are showing themselves to be effective in both scenarios. Could their scaly skin be the answer?

The use of sterilized fish skin to treat the California bears was borne out of sheer necessity. Captivity was taking a toll; their paws simply needed to heal faster. “I kept thinking, what else could we do,” Peyton said. “And that’s when I remembered seeing the stories from Brazil.”

In March, Stat News published a story about doctors in Brazil conducting clinical trials to use sterilized tilapia skin as a bandage for second- and third-degree burns in humans.The innovation arose from an unmet need,” the report reads. “Animal skin has long been used in the treatment of burns in developed countries. But Brazil lacks the human skin, pig skin, and artificial alternatives that are widely available in the United States.” Tilapia, however, is an abundant food source in Brazil—and their skin is usually thrown away. What’s more, tilapia skin can remain on a wound for 10 days, unlike a bandage which must be constantly replaced, causing the patient pain and risking infection from outside sources.

The paws of a wild black bear, burned by the Thomas wildfire.
Karin Higgins/UC Davis

Peyton noticed that the clinical trials were going well. In July, Brazil’s Federal University de Ceara announced some early-stage findings: Patients with severe burns reported less pain overall. Healing time improved, too. Patients with deep second-degree burns that usually take 21 days of treatment averaged only 18.5 days of treatment. Most importantly, scientists reported “a reduction in the cost of outpatient treatment of around 57 percent.”

Inspired, Peyton decided to try the treatment on the wildfire-burned bears. “This is the first time that fish skin bandages had ever been used for veterinary medicine, so it was kind of an adventure,” she said. She believes the success will inform how vets treat burns in the future. “Right now we don’t have a lot of different options for treating animal burns,” she said. “Unlike for humans, we don’t have skin banks for animals, so we haven’t been able to do this type of biologic bandage.”

The revelation couldn’t have come at a more dire time. California’s 2017 wildfire season will almost certainly rank among the most destructive in recorded history, and future seasons are expected to be worse, thanks to human-caused climate change. Animals—wild, domestic, and agricultural—will be among the victims. Sure, there were many heroic rescue stories this year, like the woman who shoved her pony in a Honda Accord. But dozens of horses perished in December after blazes in Los Angeles. In October, one animal rescue group estimated as many as 3,000 animals were displaced by just one blaze in agricultural communities in the Napa and Sonoma valleys. Peyton, who has treated animal burn victims for several years, said most of her burn patients are now wildfire victims.

Peyton hopes the promise of a cheap treatment like tilapia skin will change the fate of animals burned in future wildfires, and is soliciting donations to UC Davis’s Veterinary Teaching Hospital for the cause—it is, after all, the only animal hospital to have treated wildlife burns this way. “It will go for further research, and hopefully to go treat wildlife in other places,” she said.

For humans, the prospect of tilapia bandages is murkier, at least in the United States. As Stat News reported, “In the U.S., animal-based skin substitutes require levels of scrutiny from the Food and Drug Administration and animal rights groups that can drive up costs” of the cheap product. U.S. hospitals also already have plenty of human skin for grafting, Stat News noted, so “tilapia skin is unlikely to arrive at American hospitals anytime soon.”

But burns in the U.S. are not the more pressing problem. Most injuries come from countries where open fire cooking and unsafe kerosene cook-stoves are prevalent. A 2016 study in sub-Saharan Africa, for example, found burns to be “important preventable causes of morbidity and mortality,” with one in five burn victims dying from complications due to a lack of investment in “in-hospital and post-discharge care.” In India, according to the World Health Organization, “over 1,000,000 people are moderately or severely burnt every year.”

Both of these are areas where tilapia farming is on the rise. Indeed, The New York Times has called tilapia “the perfect factory fish; it happily eats pellets made largely of corn and soy and gains weight rapidly, easily converting a diet that resembles cheap chicken feed into low-cost seafood.” And because the fish skin is generally disposed of, farmers wouldn’t be sacrificing product that is otherwise valuable to them. Still, the Times notes, there are potential issues with sustainability and pollution:

Environmentalists argue that intensive and unregulated tilapia farming is damaging ecosystems in poor countries with practices generally prohibited in the United States — like breeding huge numbers of fish in cages in natural lakes, where fish waste pollutes the water. “We wouldn’t allow tilapia to be farmed in the United States the way they are farmed here, so why are we willing to eat them?” said Dr. Jeffrey McCrary, an American fish biologist who works in Nicaragua. “We are exporting the environmental damage caused by our appetites.”

That pollution also has the potential to contaminate the fish’s skin—meaning proper sterilization would be necessary if doctors wanted to use it for a bandage. Thus, very poor countries without much medical infrastructure would not be well-equipped for the process, said Dr. Jeanne Lee, interim burn director at the the regional burn center at the University of California at San Diego. Still, Lee said, “I’m willing to use anything that might actually help a patient.” Thanks to the burned bears in California, we know of at least one more option.