IF YOU'VE WANDERED the aisles of sporting- goods stores in the northern Rockies, chances are you've seen Mark Matheny's face. It's the mask of blood staring at you from the counter display of Udap bear spray, which he manufactures. The photograph was taken 20 minutes after Matheny was attacked by a sow grizzly bear, which quit mauling him after his partner sprayed the bear twice with pepper spray. Since then, it's been Matheny's job to convince skeptical outdoorsmen that, in bear country, it's wiser to pack heat in a canister than in a cartridge case.