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 first. Castor and Pollux agreed. Idas quickly ate both his portion and Lynceus' portion. Castor and Pollux had been duped. They allowed their cousins to take the entire herd, but vowed to someday take revenge. Some time later, Idas and Lynceus visited their uncle's home in Sparta. The uncle was on his way to Crete, so he left Helen in charge of entertaining the guests, which included both sets of cousins, as well as Paris, prince of Troy. Castor and Pollux recognized the opportunity to exact revenge, made an excuse that justified leaving the feast, and set out to steal