Ask a Bear: Why Do Grizzlies Have Humps?

Q: This one’s for the grizzlies: What’s that big hump between your shoulders? —Anonymous, Boulder, CO

A: So you want to know about my hump? My hump, my hump, my hump? My lovely beary bump? Well, that junk I’m carting around in my trunk isn’t just for show: It’s an essential tool, and it helps me live my wonderful, wild life.

Bears aren’t the only animals that have a hump. Camels, for example, use their famous humps to store fat, which helps them survive in their resource-poor native habitat. In contrast, my hump is actually a big lump of lean, mean, organic muscle. That’s right, muscle—I’ve never skipped back day in my life.

So why do I need such a ripped back? In short: to dig. You see, despite my reputation as an apex predator, I prefer small game. Tiny, actually: The occasional salmon or carrion binge aside, my favorite foods include grubs, insects, and tubers, most of which live in or on the ground. To get at them, I need to make like a steam shovel and dig, excavating out those delicious wiggly worms and juicy roots. These Schwarzenegger-like shoulders I’m sporting give me the power I need to do just that. I can also use those guns to flip over rocks and bash apart rotten logs in search of a meal.

My hump doesn’t just help me feed myself, though. It helps with denning as well: In the winter, I can use it to help excavate my den, and in the spring, I use my powerful forelegs to dig my way out of my winter hide. That hump is a distinctive part of my look—in fact, looking for it is one of the best ways to tell grizzlies apart from our smaller cousins, black bears. My relatives don’t have shoulders as swole as mine, so they don’t have any noticeable humps.

But, I’m not the only bear that has a hump: Look closely at polar bears, and you’ll notice they have a muscular hump of their own on their upper back. Like ours, their humps help them feed themselves, in their case by breaking into seals’ dens or pouncing on ones they find on the ice. Sounds a little messy to me, honestly. I think I’ll stick with my grubs.

—BEAR