The caliber of choice for a "trail gun" depends on what "wildlife" you expect to run across.
If you are hiking trails in the Ouachitas, Ozarks, pine woods of Louisiana or Hill Country of Texas, its much more likely the most dangerous animal you'll come across is another human. Cougars, coyotes, feral hogs are possible but will typically head the other way.
I would feel perfectly safe with a .22 kit gun, Glock 26 or Ruger LCP.
The Beretta 84 is a fine and beautiful handgun..........but it almost makes me want to laugh that it was being touted as a trail gun. Kinda like advocating a Lexus as an off road vehicle. Sure, you can do it...but there are more appropriate choices.
In Alaska, that trail gun better be 10mm, 44mag or even better a rifle. Of course a .22 round to your buddies foot or leg will allow you to escape most any bear.
A snake lying in the trail? Go around him.
If you feel the need to obliterate him to prove it's your trail....use a stick or big rock, its quiet and costs nothing. A good 5ft hiking stick is my favorite trail tool and I've used one several times to nudge a snake out of my way. When I was younger I followed the theory of SNAKE! OMG! KILL IT! SHOOT IT! BURN IT WITH FIRE! If I'm traveling through HIS territory, he lives.
(not applicable to serpents that find their way into MY yard...they're DRT)