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.
Resinoid (perfumery) Resinoid (perfumery) Resinoids are extracts of resinous plant exudates (balsams, oleo gum resins, and natural oleoresins). Resinous plant exudates (balsams, oleo gum resins, and natural oleoresins) and animal secretions (ambergris, castoreum, musk, and civet) are extracted with solvents such as methanol, ethanol, toluene, or acetone. Yields range from 50 to 95 %. The products mainly consist of nonvolatile, resinous compounds. They are usually highly viscous and are sometimes diluted (e.g., with phthalates or benzyl benzoate) to improve their flow and processing properties. Resinoids are mainly used as perfume fixatives. The resinoids described above should be distinguished from prepared oleoresins (e.g.,