Three recent cases of bear attack in Wyoming illustrate the flaws in studies purporting to show that bear spray is superior to firearms as a defense against bears. On September 20th, 2014 the following incident occurred. From county10.com:
(Dubois, Wyo.) – The Wyoming Game and Fish Department and the U. S. Fish and Wildlife Service both confirmed today that a third bear incident occurred this past weekend, on Saturday in northwestern Fremont County. In this incident, Lander Large Carnivore Specialist Brian DeBolt said a Grizzly bear was shot and killed “in an act of self defense” in the East Fork drainage east of Dubois. He said the bear was an adult male. He said there were no reported injuries in the incident.
It appears that in the above incident, a defense with a gun worked without any injuries to the defending humans.
There was another attack a day later, this time from a sow with cubs. It occurred on September 21, 2014. From ktvq.com:
DeBolt said the man suffered only minor injuries from a bite to his side. The man’s partner sprayed the bear with bear spray, causing it to stop its attack and retreat. The pair was then able to pack out and get to help.