information:extraction, information:filtering
Antlers

Only the stags have antlers, which start growing in the spring and are shed each year, usually at the end of winter. Antlers typically measure 71 cm (28 in) in total length and weigh 1 kg (2.2 lb), although large ones can grow to 115 cm (45 in) and weigh 5 kg (11 lb). Antlers, which are made of bone, can grow at a rate of 2.5 cm (1 in) a day. While an antler is growing, it is covered with highly vascular skin called velvet, which supplies oxygen 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.