Drier, warmer winters and increased access to delicious garbage are causing an increasing number of bears to forgo hibernation.
The Nevada Department of Wildlife responded to 97 calls about bears last year, a dry winter. This is up from 40 calls in 2009, a snow-heavy winter.
Chris Healy, a spokeperson for the NDOW, told NBC News, "Over the years during the light winters, some bears will sleep five or six days out of the week and wake up on garbage days when they know there will be garbage available."
A black bear in Lake Tahoe made headlines earlier this week when he interrupted a ski race at a resort.
Bears typically deep sleep during winter due to cold temperatures and the unavailability of food. However, with readily accessible garbage and warmer temperatures, confused ursines often mistake good weather for a spring thaw.
"It's reasonable to expect the bears not to hibernate when warmer temps are present," according to California Department of Fish and Wildlife spokesman Lt. Patrick Foy, after a bear was spotting lounging off-season in Yosemite National Park.
In Juneau, Alaska, residents report frequent sighting of a black bear that seems more interested in raiding bird feeders and trash cans than getting its sleep.
Officials across central Florida have reported an upswing in non-denning, garbage-eating bears in the last month, while bears in Finland have been forced from their dens due to heavy rains and flooding.