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 of Tyndareus alone, but they were sons of Zeus in the Hesiodic "Catalogue" (fr. 24 M-W). The conventional account (attested first in Pindar, Nemean 10) combined these paternities so that only Pollux was fathered by Zeus, while Leda and her husband Tyndareus conceived Castor. This explains why they were granted an alternate immortality. It is a common belief that one would live among the gods, while the other was among the dead. The figure of Tyndareus may have entered their tradition to explain their archaic name "Tindaridai" in Spartan inscriptions, or "Tyndaridai" in literature, in turn occasioning incompatible accounts of