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 oil ricin. Since castor oil is sometimes used to induce labor in full-term pregnancies (scientific evidence of its effectiveness is lacking), consuming castor oil to treat constipation is not considered safe in pregnancies that are not at full term yet, as it may cause contractions of the womb. Castor oil Castor oil is a vegetable oil pressed from castor beans. The name probably comes from its use as a replacement for castoreum. Castor oil is a colourless to very pale yellow liquid with a distinct taste and odor. Its boiling point is and its density is 961 kg/m. It is a