Answer:
It is the great nemesis of the lactose intolerant.
Brown I am and much admired; many horses have I tried; tire a horse and worry a man; tell me this riddle if you can.
What stays on the ground but never gets dirty?
What points the way without a hand. It floats on water but exists on land?
Face with a tree, skin like the sea. A great beast I am. Yet vermin frightens me.
I break away from my pack. I create holes in my victims. I can travel for miles and then disappear. I am part of a dying breed. What am I?