If you've never seen a grizzly bear get funky in the forest when he thought no one was watching, do yourself a favor and click "play" on the song below. Wait a bit (I recommend the 12-second mark) and then hit "play" on the video. Enjoy — and I'll explain the science behind this exercise in a moment.
So, by now you know that grizzly bears don't really "dance," but there's a lot to be learned from their smooth moves.
Wildlife cameras captured this video, as well as numerous others, as part of the USGS Northern Divide Bear Project, a five-year study that provided scientists with a better understanding of the grizzly population in northwest Montana.
Researchers collected fur from 4,795 bear rubs — trees and other objects that bears rub on — and 2,558 hair-snag stations, strategically placed barbed wire baited with a scent lure.
Then they analyzed the 34,000 samples to determine that 765 grizzlies made their home in the Northern Continental Divide Ecosystem, an area considered to have the best prospect of long-term survival for the species.
How do you identify a bear rub?
Bears rub on a variety of objects — fence posts, telephone poles, boulders, the walls of buildings — and unsurprisingly, trees are one of the most common.
A typical bear-rub tree is often smooth and lacking branches, and it may also be discolored from the act of rubbing, as well as dirt from bears' fur. There may also be fur caught in the tree.
Often, there's a lack of vegetation growing around the tree, and some trees may even have a path leading to them from all the bear paw-traffic.
Why is that bear 'dancing'?
There have been numerous theories as to why bears rub on trees — everything from scratching an itch to using tree sap as insect repellant — but a University of Cumbria study revealed that male grizzlies rub on trees for a very different reason.
The two-year study of British Columbia grizzly bears used cameras and satellite equipment to determine which trees bears rubbed on and how they moved through the terrain.
Male bears were most likely to rub on trees, and researchers concluded that the grizzlies were marking the trees as they searched for breeding females.
Ecologist Owen Nevin, who led the study, thinks that by marking the trees, the bears get to know each other and avoid potential conflict over mates.
"Big male bears can seriously injure or even kill each other when they get into a fight," he told LiveScience. "If one recognizes the other from the scent marks on the rub trees in the area, he knows he's in for a tough fight — he's on the other guy's patch so to speak — so it might be better to back away than make a serious challenge."
However, adult grizzlies aren’t the only ones who like a good rub against a tree. Even bear cubs have exhibited the behavior.
Nevin says cubs are likely rubbing against the same trees in order to trick adult bears.
Like other species, a male grizzly will sometimes kill a female's offspring in order to mate with her, a behavior known as sexually selected infanticide. By rubbing on the tree after an adult bear, the cub may be attempting to smell more like the adult grizzly.
"They can visit the tree two or three times in a day, sometimes within an hour of the big male, so it may be that smelling like him makes them safer," Nevin said. "Related animals smell similar and animals are less aggressive toward relatives."
Take a look at a "dancing" bear cub in the video below, and go ahead and click "play" on that song again. You won't regret it.
Related on MNN:
- How to survive a bear attack
- Bears require bear spray, but how to recycle it?
- Watch a deer play in a mud puddle (Yakety Sax cut)