One of my friends hiked the CDT a dozen years ago or so and he thought that it be a wise idea to carry a .44 Magnum for defense against Grizzlies and/or Mountain Lions; he wasn't even out of NM when he shipped that thing home because it was too damn heavy to carry all day everyday.
If you study ballistics there's not too many pistol rounds out there that carry the lethality of a Rifle round or a 12 gauge slug. My go to pistol is the 9mm, I've qualified expert with it in the DHS advanced pistol course, it's light to carry and comfortable and easy to shoot (I probably would not have been able qual expert with a .40 as it's more difficult to get follow up shots as quickly due to the extra recoil/snappiness of the .40). Another reason many like myself choose 9mm is it's cheap, shooting is like flying you gotta practice to stay proficient and it's easier on the wallet to mow through a couple boxes of 9mm than .40 (it's ~ 30% cheaper than .40). Depending on how much you shoot that savings can add up over time (or if you're like me you just shoot more rounds negating any savings
For anyone getting ready to buy their first handgun with aspirations to carry I say go for a Glock 19 and 1000 rounds of ammo. It's proven gun that's cheap to buy with cheap mags and cheap ammo. (I don't even own any Glocks, but for new shooters it's tough to beat). If I were going to be flying somewhere that if I went down and it might take a long time for search and rescue to find me (like weeks/never) and needed a survival rifle I'd have a 10/22 take down model in the plane. Packs small and is light weight and I can shoot enough rabbits/squirrels to feed me for awhile.
Will a 9mm stop a griz in it's tracks? No way, but a .40 probably won't either. If I'm going into Griz or Mountain Lion Territory (the latter is my backyard) I keep my eyes open and try to avoid an encounter, same thing if I'm in the 'hood.



. And, no salt for the hide.....