The Bear Necessities
When I was a kid, my dad asked me a simple question. Do bears hibernate? With great certainty and conviction, I said yes. He looked down at me with all the fatherly love he could muster and said…nope, and like an actor slowly walking away from an explosion, my father took his leave. I was in shock and sat there contemplating if my whole life was a lie. I was a dramatic child. Fast forward to now and here I am asking you the same question. Do bears hibernate? Today we are learning why bears do not hibernate...sorta, it’s complicated.
We all know that bears spend the summer and fall months putting on as much weight as possible in order to prepare for their winter snooze. This has created the best event ever called *Fat Bear Week* (Thank you Katmai National Park). We’ve been taught that this bear snooze-fest is called hibernation, but technically, bears enter a state known as torpor. Similar to what teenage boys go through, torpor is a state of reduced activity. During torpor, a bear’s body temperature and heart rate decrease, but they can still wake up, move around, and it’s usually during this time that females give birth to cubs.
So, what is hibernation, then? Like torpor, hibernation is a state of extended inactivity, or dormancy. In hibernation, an animal’s body temperature and heart rate drop drastically, and they can’t be easily woken up. My dad explained it this way: if you picked up a ground squirrel and shook it (not that I recommend doing this!), it wouldn’t wake up. However, if you tried to pick up a bear and shake it (how, Dad…how?), you’d end up with one very ticked-off bear. If you haven’t heard the phrase “don’t poke a sleeping bear,” this is your main takeaway!
If bears go through torpor, then clearly bears don’t hibernate, right? Well…funny story.
Recently, two changes have led to bears sort of being classified as hibernators. One change is that the dictionary definition of hibernation was expanded to include bears (who knew they could just change that?). Now, there’s “hibernation” and “true/deep hibernation.” Animals that undergo deep hibernation include ground squirrels, bees, groundhogs, bats, hedgehogs, and others. The other change is ongoing research, which constantly reveals new insights. A recent longitudinal study (conducted over several seasons) showed that some bears experience greater physiological drops than previously thought, suggesting that bears might have the ability to hibernate. So, do bears hibernate? Sort of!
That’s it, right? Not quite! I have one last fun fact for you. It’s super interesting that the level of seasonal sleepiness in bears changes depending on how far they are from the equator. It’s not set in stone, but zookeepers have noticed some trends. For example, the black bears my friend cared for in Oklahoma entered a deeper torpor for a longer period than the black bears I cared for in South Florida, who just slept in a bit and were sluggish. This has to do with food availability, which is year-round in warmer, tropical areas. Bears that live in tropical regions, like Sun bears, don’t go into torpor at all.
I hope you enjoyed this extra info dump! We’re back to our regularly scheduled programming. Thanks!
The bracket from last year’s Fat Bear Week. It’s so much better than March Madness.
