Perhaps Locke believed that he wouldn't be smelled. He's not a zoologist (or so we think...) and a lot of people don't know about the polar bear's sense of smell, which is freakin' awesome.
It would have been a lot funnier if he started rolling around in bear excretements, though. Scat, poo, feces, whatever you wanna call it, it would have been funny as crap (HA! It's a pun!). lol.