The thing about MMA fighters is that they know in the back of their minds that no matter how bad things get for them in the MMA ring, there is a ref there to make the call and halt the violence if need be. There is also an understanding with their opponent that certain tactics - ball kicks, eye gouges, etc. - are off limits and neither of the combatants are out to kill or maim.
Wild animals don't have that understanding. They don't "sign the waiver".
