Pelage and Surface Topography of the Northern Fur Seal
The pelage of the adult seal is composed of clearly defined bundles, each with a coarse guard hair and 35 to 40 fine underfur hairs; there are more than 300,000 fibers to the square inch.
The pelage of the adult seal is composed of clearly defined bundles, each with a coarse guard hair and 35 to 40 fine underfur hairs; there are more than 300,000 fibers to the square inch. Each guard hair is accompanied by a sweat gland and two large sebaceous glands. Area of the haired surface of the body of the adult male is about 2.5 times that of the female.
The pelage of the pup resembles that of certain land carnivores in having small, scattered bundles, each containing one to three fibers, some of the fibers being underhairs and some overhairs (guard hairs). The first molt, from black birthcoat to silvery, adult-type molt, occurs about mid-September, the second in August of the following year (on the yearling), the third in September of the following year (on the 2-year-old), the fourth and subsequent molts in late September or October. The molt in the adult takes 4 or 5 months. Molting has little effect on the commercial value of a sealskin, provided the skin has been taken before September.
Dominant color of the adult pelage is light brownish gray; most seals are darker on back and chest, lighter on belly, throat, and sides. Color patterns of the sexes are indistinguishable up to 2 or 3 years old; color patterns of seals from American and Asian waters are indistinguishable. Colors are brighter (less brownish) in winter when the seal is at sea and has completed its autumnal molt.
In addition to mutant color phases, such as albino, piebald, and chocolate, one may see atrichia, pediculosis, pachyderma, and other skin disorders; and foreign growths, including marine algae and barnacles, on the guard hair. The flippers are naked. The only functional claws—used exclusively for grooming the pelage — are on the middle three digits of each hind flipper. The blubber on the fur seal is thinner than on phocids or hair seals. From a fur seal weighing 66 pounds about 0.6 gallons of blubber oil can be rendered.
Victor B. Scheffer. Published by U.S. Fish and Wildlife Service (February 1962).