North American beaver large, webbed hind feet. The unwebbed front paws are smaller, with claws. The eyes are covered by a nictitating membrane which allows the beaver to see under water. The nostrils and ears are sealed while submerged. A thick layer of fat under its skin insulates the beaver from its coldwater environment. The beaver's fur consists of long, coarse outer hairs and short, fine inner hairs (see Double coat). The fur has a range of colors, but usually is dark brown. Scent glands near the genitals secrete an oily substance known as castoreum, which the beaver uses to waterproof its fur.
Castor wax Castor wax Castor wax, also called hydrogenated castor oil, is an opaque, white vegetable wax. It is produced by the hydrogenation of pure castor oil often in the presence of a nickel catalyst to increase the rate of reaction. The hydrogenation of castor oil forms saturated molecules of castor wax; this saturation is responsible for the hard, brittle and insoluble nature of the wax. Castor wax is used in polishes, cosmetics, electrical capacitors, carbon paper, lubrication and coatings and greases where resistance to moisture, oils and petrochemical products is required. Castor wax is also useful in polyurethane coating formulation, as