It is more common for antlers to fall off one at a time rather than together, and bucks are often seen with a single antler. Antlers are grown and shed annually and are usually dropped after the breeding season, from mid-December through February. If the antlers were grown for defense against predators, they would not drop in winter, when deep snow puts the deer in the greatest danger.
The breeding or rutting season starts about the last week of October when the bucks, previously indifferent to the does, begin to court them. As the rutting season peaks during the last two weeks of November and continues into December, bucks often engage in severe fights using both their antlers and hoofs, for position of the doe. The bucks in the finest condition and having the largest racks are usually the first to drop their antlers. On rare occasions a doe has been observed with antlers, but hers are usually small and greatly modified.
Many people are not aware that bucks shed their antlers because they have never found the shed antlers, which are difficult to see as they become covered with leaves and snow. During this time wild mice and other animals gnaw them because of their high calcium and phosphorus content, and by summer most of the antlers have been consumed.
A buck is without antlers until April or May, when new growth begins and continues for about 15 weeks. The antlers harden into bone about five months after growth begins.