Revolvers are all that you need. Revolvers come in the power levels necessary to take down any animal worldwide. As a woods carrying firearm the revolver is second to none. It works more reliably than the semi-auto and can handle more kinds of ammunition due to the use of a rim to hold the base of the cartridge and common diameters of bullets. For example, the 460 X-frame from Smith and Wesson can shoot 460 Smith and Wesson, 454 Casull, 45 Long Colt and 45 Schofield all because of the diameter in common and the rim that holds the cartridge from sliding forward in the cylinder.
A 10 mm semi-auto can also be used because of the availability of good ammo made to increase its penetration. But a revolver is as good as it gets in my opinion.