By that, i mean what would you consider the most difficult based on the animals intelligence? I have only hunted whitetails for 25 years, so I have no input. I have always read that a mature whitetail is the hardest to kill, I have killed them, but I have nothing to measure it against. Are things like moose, elk, bear,sheep etc, just as witty and difficult to kill? What is your experience on this? I don't mean difficult as in the terrain or accessibility, just based purely on the animals' smarts.