You really would not want to threaten this old man. I can’t still handle the recoil from a .44 magnum snub-nosed revolver well enough to be sure of getting off subsequent shots both quickly and accurately, but the .357 magnum is big enough for two-legged predators.
Yep - .357 can take out 3 at a time if they're lined up right. .357 with 6" barrel and .38 Special hollow point will do the job on most bipeds too.