via PBS:

Understanding the strange hibernation patterns of American black bears may give scientists new clues on how to protect the brains of stroke and heart attack patients.

The metabolism of a black bear falls sharply during hibernation, to 25 percent of their normal body rate, while their body temperature stays relatively high, researchers reported on Thursday in the journal, Science. Unlike small hibernating animals, this indicates that black bear metabolism acts independently from body temperature, controlled by an unknown mechanism. Researchers called the findings surprising.

When most hibernating animals, such as ground squirrels, bats and marmots, fall into a state of torpor, they get cold as icicles, and their inner thermostats plummet to near or below freezing. These temperature changes affect every single biological reaction in their bodies, said Craig Heller, professor of biology at Stanford University and an author on the study.