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.
Animal welfare exhibit normal behavior patterns, to be housed with, or apart from, other animals (if applicable), and to be protected from pain, injury, suffering and disease. Anyone who is cruel to an animal, or does not provide for its welfare needs, may be banned from owning animals, fined up to £20,000 and/or sent to prison for a maximum of six months. In the UK, the welfare of research animals being used for "regulated procedures" was historically protected by the Animals (Scientific Procedures) Act 1986 (ASPA) which is administrated by the Home Office. The Act defines "regulated procedures" as animal experiments that