and nutrients to the growing bone. The antlers are testosterone-driven and as the stag's testosterone levels drop in the autumn, the velvet is shed and the antlers stop growing. With the approach of autumn, the antlers begin to calcify and the stags' testosterone production builds for the approaching rut (mating season). European red deer antlers are distinctive in being rather straight and rugose, with the fourth and fifth tines forming a "crown" or "cup" in larger males. Any tines in excess of the fourth and fifth tines grow radially from the cup, which are generally absent in the antlers of smaller red deer, such as Corsican red deer. Western European red deer antlers feature "bez" (second) tines that are either absent or smaller than the brow tines. However, bez tines occur frequently in Norwegian red deer. Antlers of Caspian red deer carry large bez tines and form less-developed cups than western European red deer, their antlers are thus more like the "throw back" top tines of the North American elk (C. canadensis), known as maraloid characteristics. A stag can (exceptionally) have antlers with no tines, and is then known as a switch. Similarly, a stag that does not grow antlers is a hummel. Coat European red deer tend to be reddish-brown in their summer coats, and some individuals may have a few spots on the backs of their summer coats. During the autumn, all red deer subspecies grow thicker coats of hair, which helps to insulate them during the winter. Autumn is also when some of the stags grow their neck manes. The autumn/winter coats of most subspecies are most distinct. The Caspian red deer's winter coat is greyer and has a larger and more distinguished light rump-patch (like wapiti and some central Asian red deer) compared to the Western European red deer, which has more of a greyish-brown coat with a darker yellowish rump patch in the winter. By the time summer begins, the heavy winter coat has been shed; the animals are known to rub against trees and other objects to help remove hair from their bodies. Red deer have different colouration based on the seasons and types of habitats, with grey or lighter colouration prevalent in the winter and more reddish and darker coat colouration in the summer. Distribution The Cervus genus ancestors of red deer first appear in fossil records 12 million years ago during the