Why not? A group of researchers at Washington State University published a study in Communications Biology in September that sought to better understand what goes on in the cells of hibernating grizzly bears. The university is home to the W.S.U. Bear Center, the only grizzly bear research center in the United States; it houses 11 bears that were either raised in captivity or relocated to the center after being identified as problem bears in the wild.

Researchers took samples from the liver, fat and muscle of six captive grizzly bears at three times during the year. In the lab, a team of researchers analyzed the DNA to understand the changes that occur in the cells over the course of the year.

“The effect of hibernation on each tissue is different,” said Joanna Kelley, an evolutionary biologist at Washington State University and one of the paper’s authors. “Hibernation is not just as simple as hibernating and not hibernating. There are transitional things happening throughout the year.”

The team found that the bears’ fatty tissues changed the most during hibernation, whereas the muscle tissue hardly changed at all. The muscle cells remained active through the hibernation period, which might help explain why those tissues do not atrophy.

Most surprising to Heiko Jansen, the study’s lead author, was that the bears’ fat contained a large number of genes that change their level of expression over the course of the year . “It’s in the thousands,” he said. In contrast, when dwarf lemurs in Madagascar hibernate, only a few hundred genes in their fat tissues change their level of expression seasonally.