If you are talking true predation you have to leave the human element out of it..
That is because killing the other predator is not neccassarily utilizing it for food.. Sometimes it is just for the killing. Such as for a trophy.
In that context great white sharks, eagles, lions, tigers, and the grey wolf come to my mind.. I am sure that there are others..
How many are Keystone predators though?.. James L.
