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 in July 2007, Indian castor oil sold for about US$0.90 per kilogram (US$0.41 per pound) whereas U.S. soybean, sunflower and canola oils sold for about US$0.30 per kilogram (US$0.14 per pound). Annually 270,000–360,000 tonnes (600–800 million pounds) of castor oil are produced for a variety of uses. In the food industry, castor oil (food grade) is used in food additives, flavorings, candy ("e.g.", polyglycerol polyricinoleate or PGPR in chocolate), as a mold inhibitor, and in packaging. Polyoxyethylated castor oil ("e.g.", Kolliphor EL) is also used in the food industries. In India, Pakistan and Nepal food grains are preserved by the