Fur, the hairy covering on the skin of certain mammals. Most fur consists of two layers–underfur, the short, soft, curly hair next to the skin; and guard hair, the longer, stiffer hairs covering the underfur. These two layers, together with the skin, make up the pelt. Fur keeps animals warm because the hairs retain a layer of air that serves as insulation against the cold. Fur made into garments provides warmth, and also gives some wearers a sense of luxury. Fur garments include jackets, coats, neckpieces, and hats.

Good quality fur is lustrous and is uniform in color, depth, and texture. The skin, or leather side, is soft and supple, but firm and strong. Buyers of fur garments are protected by law against mislabeling. The label must state the name of the animal, whether the garment has been dyed or otherwise altered, and the country of origin. Pile fabrics that resemble furs are usually made of synthetic fibers.

Animals grow heavy, thick coats of fur during cold winters and at high altitudes, and thinner coats in warmer areas. Animals in snowy regions are generally light in color; those in warmer, forested areas are usually of a darker shade. Changing seasons also affect fur. Animals that become dormant in winter eat heavily and have fur of excellent quality in fall; when they awaken, they are thin and their fur is faded.

The best fur is taken soon after an animal reaches maturity. Very young animals have thick pelts, but the hair is too soft and the skin too tender for use in garments. An old animal's coat is coarse and shaggy.