but how would you really know when something is bearproof?k abc's gloria riviera. >> reporter: in west yellowstone, montana the bears are boss. >> oh, man. >> reporter: breaking into these manmade products their singular goal. >> this bear has a nickname. >> buck the destroyer. >> reporter: it's not just play, it's their day job. >> she got in that first little bit and then started tearing apart on the styrofoam. >> reporter: these grizzlies are grizzled vets, testing products to certify as bear resistant before they hit the market. >> reporter: the mama bear and her two cubs were rummaging through a dumpster looking for food. >> reporter: bears getting too close for comfort happens all too often. the lure of an easy meal tempting bears out of the wild and into breaking into houses like this one in colorado. ♪ but here at the curiosity asset. >> he's going for it. >> repzly, about 1,200 pounds p times that of a human.e these b ich regions of theof 700 pounds. u.s. and canada up to 1,700.the business 30 years. he's come from arizona to to th.

but how would you really know when something is bearproof?ar goal. >> this bear has a nickname. >> buck the destroyer. >> reporter: it's not just play, it's their day job. >> she got in that first little bit and then started tearing apart on the styrofoam. >> reporter: these grizzlies are grizzled vets, testing products to certify as bear resistant before they hit the market. >> reporter: the mama bear and her two cubs were rummaging through a dumpster looking for food. >> reporter: bears getting too close for comfort happens all too often. the lure of an easy meal tempting bears out of the wild and into neighborhoods. sometimes even breaking into houses like this one in colorado. ♪ but here at the grizzly and wolf discovery center, that curiosity and that fight become assets. >> he's going for it. >> reporter: the bite force of a grizzly, about 1,200 pounds per square inch, is nearly eight times that of a human. here in yellowstone these bears can weigh upwards of 700 pounds. in some food-rich regions of the u.s. and canada up to 1,700. bill

. >> reporter: and if you pass, bearproof. >> you're done. >> reporter: you're done. okay. >> then you get a certificate. >> reporter: you get a certificate and your product on the market. >> that's right. >> reporter: round one is called. halfway there. >> it's holding up. >> reporter: it's holding up. >> it's still early. it ain't over till it's over. >> reporter: it ain't over till it's over. >> grizzly bears are truly opportunistic omnivores. their diet changes from day to day, from season to season, from year to year. >> reporter: the man who knows more than most, dr. frank van manon, a leading bear scientist devoted to these majestic animals for nearly 30 years. you have said that we might encounter what? >> a bison on the road. >> reporter: and what do we have in front of us? this guy does not look worried to see us. he's coming straight for us. look at him. that was amazing. >> reporter: here the grizzlies' natural habitat. but just outside modern-day development. >> on one hand you have the park over here. and then you can hear -- there's a semi truck just ba