Yes, female reindeer, also known as does, do drop their antlers during the winter months. This is a natural process called "antler shedding" and is a way for the reindeer to conserve energy and resources during the cold, harsh winter months. The antlers are made of bone and are covered in a thin layer of skin called velvet, which contains nerves and blood vessels. As the weather gets colder, the reindeer's body will begin to redirect its resources to maintaining its core body temperature and producing energy, so the antlers will gradually fall off.