“There was quite a bit of concern about lynx in the state, which is why we initiated this study,” said Dan Thornton, a senior author of the study and an assistant professor at Washington State. “That concern is warranted given what we found.”

No one knows the exact number of lynx in the region, though the Washington Department of Fish and Wildlife estimated in 2016 that there were about 54 animals, an estimate that Dr. Thornton’s analysis supports.

But the situation is probably even worse than what the Washington State team recorded just a few years ago, Dr. Thornton said. In 2018, catastrophic forest fires burned through some of the areas that still had lynx. The habitat area affected by the fires will likely take 20 to 40 years to recover, he said, by which point the climate will have warmed further and the lynx will be even less likely to move back in.

“It becomes a spiral downward, which is what we’re worried about,” he said.

The lynx population is believed to be healthy in Alaska and parts of Canada — though there isn’t a lot of solid research about lynx near the Canada-United States border, or how they interact with populations in the lower 48 states, Dr. Thornton said. In Canada, it’s still legal to hunt or trap the animal.

Climate change is likely the main reason for the declining population, he and other lynx experts said, driving a combination of factors: warmer temperatures, which the cold-adapted lynx don’t like; forest fires; and less snow cover, which reduces the animal’s competitive advantage and won’t support its main prey, the snowshoe hare.