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 and Pollux (Prado) into the Prado (catalogue number Catalogue Nr. E.28). The erroneous identification with Antinous generated high interest in the sculpture, with large numbers of copies being produced, largely made in Italy and Northern Europe and based on plaster casts rather than made in Spain and based on the original there. These inevitably stoked the interest by obscuring the fact that the Antinous head was in fact a restoration, instead smoothing the two into a meaningful whole (as did the casts on which they were based). Main site about copies of the Ildefonso (or Castor & Pollux) group : http://www.antinoos.info/copies1.htm Copies Castor