Two make elks checking in with each other to make sure they are keeping warm in a Spring snowstorm on Lookout Mountain, Colorado. Bull elk shed their antlers ever year usually from February to April. As testosterone levels decrease osteoclasts cells form where the skull and antler meet. These cells reabsorb calcium from the antler, weakening the joint between the skull and antler until the antler drops. The fallen antler provide calcium, protein and potassium for smaller mammals. The bull elks quickly begin growing new ones.