Scientists have reported some rare good news from the Arctic. As the climate changes and the ice melts, in at least one region polar bears are thriving—finding new ways to survive and even packing on the pounds.

“A fat bear is a healthy bear,” Jon Aars, a senior scientist at the Norwegian Polar Institute, told CBS News on Thursday.

For more than 20 years, he has been tracking polar bears in the remote, arctic Norwegian archipelago of Svalbard. He led a team of researchers who meticulously monitored the weight and size of almost 800 bears between 1992 and 2019.

They found that the polar giants are in good shape, able to survive and continue to raise new cubs.

“I was quite surprised,” Aars admitted, “because we’ve lost so much sea ice since I started.”

Scientists have been raising the alarm for years that shrinking sea ice could threaten polar bears, which use the ice as a platform to hunt seals.

“Some of us would predict that we should be in trouble by now,” Aars said.

But what his team found suggests that the bears are adapting to smaller patches of ice, and may even help them hunt more efficiently because their prey, which also relies on the ice, is concentrated in smaller areas.

“I think this shows they need less ice than we thought,” Aars told CBS News.

His team’s research also found that melting ice is forcing polar bears to get creative on land – where they increasingly feed on other prey, such as reindeer and walrus.

“Some of them would now be on land as much as 90 percent of the time, which is a lot,” he said.

While the successful bears are undoubtedly good news, Aars stressed that more research is needed to understand how polar bears in other parts of the Arctic are adapting to a warming climate. And he cautioned that his team’s research does not attempt to predict how animals will cope with continued Arctic warming.

“The bears can still handle the situation as it is today,” he said. “The bad news is that (such) predictions are that we will quickly lose sea ice on Svalbard.”

Aars and many other scientists remain concerned, in other words, that the Svalbard bears’ gains will be temporary and could be reversed.