We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
If they are close enough to you that you need a gun, and you want to keep it in a small basket, I would go with a 40 S&W caliber handgun. I love the Sig Sauer p226, though it is a bit pricey: https://www.sigsauer.com/CatalogProductDetails/p226.aspx
My wife loves her p238 (and she is very accurate with it) https://www.sigsauer.com/CatalogProductList/pistols-p238.aspx
I don't know if a .380 auto bullet would drop a mountain lion, but I am sure that if you hit the cat, it would leave you alone IN A HURRY. And even if you miss, the shot is loud enough to make most animals head for the hills quickly.