Pat, I don't mean to hyjack this thread--by the way I am really impressed by the training of the King Charles Spaniels to "go on command"!
http://tinyurl.com/5rdg5 is one study of the effect of "Bear Spray".
http://www.canadianrockies.net/Grizzly/pepperspray.pdf Retrospective.
http://www.udap.com/safety.htm Gives some good safety tips--and better to avoid than confront!
I realize that there are a lot of folks on this forum who live in Alaska and deal with Grizzly's every day. We spent 4 "summers" (April thru October) in Alaska. 3 on the boat one in an RV and had multiple bear encounters. One of our friends gave us the Bear Repellant the first year. It was (and still is) carried on my gun belt--with a .44 magum. If we got into a potentially dangerous encounter (which rarely happened), the .44 was in the right (gun) hand and the spray was in the left hand. The perticular bear spray unit we own has a range of 30 feet (not much when dealing with a Grizzly) and 10.2 oz of 10% Oleoresin Capsicum. . We have practiced with it to identify the range and practiced with it (and got a new one for "real"). Parks Canada recommends that you carry bear repellant:
http://www.pc.gc.ca/pn-np/inc/PM-MP/vis ... t12a_e.pdf
A .44 magnum is not the gun of choice if dealing with a Grizzley bear--but was much easier to carry than a rifle or shotgun with slugs. We have Garrett Cartridges 310-grain Super-Hard-Cast Hammerhead bullet in the revolver.
When we were going into one part of Queen Charolette Island the Ranger specifically asked us to carry bear repellant. There are very strict laws about shooting Grizzly bears. We spent several days at Pack Creek. We talked to the rangers there, who said that since using the bear repellant, they had not had to shoot a grizzly.
I have a real respect for bears based on some of my experiences earlier in life. I used to go solo back packing in the Sierra. We have had a number of bear encounters, but the most frightening was when I was alone near Bishop Pass in late June (still snow on the ground) and sleeping under a tarp. A black bear came round in the night and sniffed and pawed me. I held my breath and played "dead"--yes I had a pistol in my hand, which was pointed at the bear's neck, but I did not fire.
Obviously I was not "dinner" that night and the bear went away. There are maulings in the Sierra every summer.