bear spray? there was a nice 1 hour documentary on animal planet on the bison herds in yellowstone. they were darting, taking samples, and tagging the animals. When 1 bison was downed, the herd still tried to protect its fallen member. the animals backed up with the approach of the scientists, park rangers, etc, but 1 was still a little pesky. they use bear mace on the thing animal (which was not being aggressive). The bison simple snorted and kept its ground. it was agitated at that point, but a second blast of mace made it back off....
now if any of you have been around large predators whether that be big cats, bears, wolves, crocodiles, etc. When they get their sights set on something or are in a fit of rage, generally a defense as "light" as bear mace won't do jacksh**. you're lucky if a combat knife can stop them. sure, plenty of attacks get fended off with just your hands alone, but those animals were generally curious and were not acting defensively or in a "rogue" nature. from the description of the attack, it wouldn't have mattered what you carried, that bear had its blinders on and was set to kill.
example: I share my backyard and nearly every possible moment outdoors in alligator country. 2 weeks ago a 10.5ft gator attacked a teenager swimming in a canal at night about 25 minutes from my house. The gator latched on to one arm when the teen was in the water. the teen fought back with his other arm and with a few punches the gator popped the arm off and left. The teenager lived. he was lucky that the alligator didnt deem him a threat. Had that gator been acting on territorial instincts and not compulsive/curious hunger, that kid would have been drowned and ripped to pieces in a matter of minutes.
a bear will act no different. bear mace is pretty futile IMO against a grizzly acting out of aggression or protecting cubs. pepper spray will be one heck of a hail mary if you're trying to stop a mother protecting its cubs or a territorial male. If the grizzly is simply exploring a campsite, sure, it'll probably shake them up pretty damn good. My best advice is to carry a substantial firearm in a tent AS WELL AS MACE. a 12g is probably your best bet if you're gonna leave it at camp. if you have to use a pistol, something .45 or a .50 would be the only thing that could make a bear flinch. if you don't believe in firearms or are unable to carry one, bearmace and anything else you can grab is about as good as anything. Keep bear mace on you WITH a firearm as well. if the situation calls for less than lethal force, you have an option to let both you and the bear walk away...but if it turns bad, you have a better chance of making it than you would with just a less than lethal method of defense.
I would be heartbroken if i had to shoot a bear. I'm a HUGE animal lover. I am an avid hiker, herpetologist (amateur until i graduate with my degree), fisherman, and hunter. Predators are amazing animals and by far the most fun to observe in the wild. You best "defense" against an animal is to prevent them from getting close in the first place. while hiking and hunting that can be a problem, but while camping it isn't. Properly storing food and disposing of trash correctly will greatly reduce the likelihood of a bear or any other "opportunist" from entering camp.
and in all honesty. do NOT freak out just because an attack occurred. hysteria is not necessary and is a terrible thing. it gets animals killed for no reason and people in trouble. just stay alert and take necessary precautions, cant do any more than that other than to not go out in the woods at all.
Id also recommend nothing short of a .45