III.

Antlers

Unlike the hollow, permanent horns of other ruminants, the antlers of deer are solid and bony. Except in the caribou, antlers form only on males and their growth is controlled by the male sex hormone. Arising from the frontal bones and nourished by a highly vascularized, fine-haired skin, called velvet, antlers complete their growth, which requires great amounts of calcium, within a few months. Circulation is then cut off, and the resulting dead skin is sloughed off as the animal rubs its antlers against trees. Antlers are used to slash territorial markings on trees or bushes, to make threatening displays, and to combat other males. Usually the fighting is stylized and harmless, but occasionally males of large species lock antlers and die of exhaustion or starvation. Moose antlers reach a width of 1.8 m (6 ft) and a weight of 20 kg (44 lb); those of an extinct giant fallow deer spread more than 3 m (more than 10 ft). Antlers in a given species may vary in size from one population to another, depending on the quality and quantity of food. In overpopulated areas that are heavily browsed, the deer usually have small antlers.