Grizzlies coming out of hibernation—spring is here!

By far, one of my favourite things about social media: Every year, around mid-March, I can refresh my Twitter feed to “watch” North America’s grizzly bears coming out of hibernation.
Sure enough, last week I found this:

Parks Canada reported its first grizzly bear of the season, spotted by a conservation officer along the Bow Valley Parkway, west of Banff.

The agency speculated that the bear was a male, since they’re typically the first to come out of their dens. Females with cubs are usually the last to rouse, around mid-May. Although there must be some exceptions, because two years ago, I tweeted this:

No doubt you learned a lot about grizzlies when they were our “Species of the Month.” Hibernation is by far one of their most fascinating traits—bears evolved to sleep through the winter months since there’s very little food, cold temperatures and lots of snow. However, bears are not considered “true hibernators,” mostly because a hibernating bear’s body temperature stays within 7°C of their normal body temperature. Unlike other hibernating mammals—like chipmunks and ground squirrels, whose body temperature drops drastically—bears can wake up very quickly when disturbed. (So don’t go poking around a sleeping bear’s den!) Also, unlike other hibernating mammals, bears don’t eat, drink, defecate or urinate during their winter sleep. Waste produced by their bodies is actually recycled into nitrogen that bears use to build protein, which maintains their muscle mass and organ tissues—bears are the only species on the planet that can do this! Still, bears may lose 15- to 30-percent of their body weight during hibernation.
Bear cubs are born in their mother’s dens, naked of fur, blind and helpless. They don’t hibernate; rather, they sleep next to their mother, nurse and grow rapidly. Keep watching Twitter, and you just might spot this year’s first cubs emerging from their mother’s dens, seeing the world for the first time. Happy Spring!