Speed and a tough/hard bullet are what you want for busting through dangerous animals skulls.
Absolutely correct, BUT not quite enough of an explanation. There is a range of speed that works best, for a given caliber and type of target. Impact angle and type of target matter as well.
SIZE of the projectile its shape, AND speed, in combination are what matter, and the "best" combination is different for different targets.
Once you have the minimum speed & energy needed, going faster might not be a benefit. For a couple of examples, I have had .45Colt 250gr SWC at 1100fps glance off an angled metal surface that a 9mm at 1100fps punched through. The same metal, at a different angle, the .45 punched through like it wasn't there.
Size, type of the slug, and ANGLE mattered here. Velocities were approximately the same.
African Elephant hunters have found that for their big .45 (or larger) caliber rifles vs. elephant skulls that a velocity range of 19-2300fps works best, punching through, where higher speeds (2500fps) had a marked tendency to glance off with a hit in the same spot.
HUNTING bear can be successfully done with lesser rounds, (such as .45acp) STOPPING a bear is a different matter.