In Utah, female black bears with young cubs typically emerge from their hibernation dens at the end of March. But when state biologists entered two dens in mid-February to count cubs, both were already empty.

A third den concealed an awake adult female bear “that almost attacked the biologists,” says Tonya Keiffer of the Utah Department of Natural Resources.

The bears were likely roused by unseasonably warm temperatures and may have wandered out looking for food, says Dale Liechty, a state bear biologist.

The bears have had their work cut out for them this spring, since plants didn’t start growing in much of Utah until weeks after the bears started stirring. (See pictures of bears.)

It’s unclear if climate change is