Most often, mule and white-tail deer loose their antlers during the month of December (moose and caribou usually loose their antlers during the winter months as well). However elk hang-on to their antlers throughout the winter and don't begin shedding them until the spring. Antler hunters search out and find the sheds and then sort them for a variety of uses, one being antler chews for dogs. If the antlers aren't found, the generally don't stay on the ground for long, —the local rodent population will begin eating the antler as a high quality source of calcium and minerals.
While the antlers are impressive to look at, they are even more impressive on an evolutionary scale...more to come!