Bear Spray or Firearms? You decide.

Spurred by this article, about a man who died from the defensive gunshot his friend fired and not by the jaws of the bear attacking him, which has been floating around the internet and my e-mail inbox at work, I thought I'd give my two cents on bear safety.
It's a very heated debate if backcountry travelers should carry bear spray or a firearm for personal protection against aggressive bears.
I will not try and influence you based on my own opinion, although I think it will be very apparent, but by the information presented below on the efficacy of specific techniques for defending oneself against aggressive bears.
This is also not a how-to on bear safety in the wilderness. For that, please visit this, that, the other, & one more good one.

From USGS's Bear Spray Safety Program handout:
'People who encounter grizzlies and defend themselves with firearms suffer injury about 50% of the time. During this same period, persons defending themselves with bear spray escaped injury most of the time, and those who were injured were subjected to attacks of shorter duration and sustained less severe injuries. Canadian bear biologist Dr. Stephen Herrero reached similar conclusions on the basis of his own research, which suggests that a person's chance of incurring serious injury from a charging grizzly bear doubles when bullets are fired rather than when bear spray is used.' (source)

From Journal of Wildlife Management's Efficacy of Bear Deterrent Spray in Alaska:
A 20 year study on 146 bear spray incidents in Alaska, involving brown/grizzly, black, and polar bears.
'Red pepper spray stopped bears' undesirable behavior 92% of the time when used on brown bears, 90% for black bears, and 100% for polar bears. Of all persons carrying sprays, 98% were uninjured by bears in close-range encounters. All bear-inflicted injuries (n=3) associated with defensive spraying involved brown bears and were relatively minor (i.e., no hospitalization required).'
'No one using bear spray was injured by black bears in any behavioral mode, aggressive, food seeking, or curious.'
'No mechanical failures of spray canisters were reported...'
'Two decades of bear spray use in Alaska confirm that it is an effective bear deterrent.'
'Wind can influence bear spray's accuracy and distance; however, our data show that wind rarely affected the outcome of bear-human interactions involving bear spray, which is likely because many close encounters do not occur in open areas, but rather in dense brush or forests where wind is greatly attenuated.'
'Because some persons had to spray bears multiple times to drive bears off in 24% of instances we studied, spray conservation, and total canister volume, may be concerns. We suggest discarding bear spray when contents fall below 90% of the original amount, or when the canister is past its expiration date, generally 3-4 years from date of purchase.'
'In Alaska, bear spray was highly effective in dealing with all 3 species of North American bears...'
'...98% of persons carrying it (bear spray) were uninjured after a close encounter with bears.'
'No bear spray has ever been reported to kill a bear.'

Rick Sinott, a retired Anchorage-area biologist for the Alaska Department of Fish & Game wrote this fantastic article arguing the effectiveness of firearms in defense of bear attacks. Excellent read by someone who really knows the topic and the mentality of both sides of the argument.

More articles:
Guns don't prevent Alaska bear attacks
A shot too late: Personal experience of how a firearm was ineffective in bear defense
NOLS kids did a 'phenomenal job': The story on what happened to the group of NOLS students who were attacked by a grizzly in Alaska in the summer of 2011

My own research:
12 gauge shotgun, short barrel, extended magazine, & ammo: 8.5 lbs
Bear spray: 11 oz

While no means of protection is 100% effective, proper bear spray usage, coupled with well-practiced bear safety techniques, can help limit the number of bears that are killed due to encounters with humans, plus the injuries, and deaths, suffered by humans.
Be responsible. It's more than just your life that your actions are affecting.

Which bears are actually the most dangerous?
Check out my previous bear post for that answer, plus another article written on the same topic.

What's the one thing I've learned in 7 years of Alaskan backcountry travel all across the state?
Good luck seeing a bear. I have a hard time finding bears, much less avoiding them.
But, maybe it's me... I swear my presence is more effective than bear spray :)