The most important feature to a fur trader though, is the thick covering of fur all over the beaver's body, except of course on the tail, which has short bristles sticking up around smooth scales. The beaver has two types of fur serving two different functions. The outer, longer guard hairs receive oil from glands and act as a waterproof coat. Underneath this coat lies a shorter thicker layer of wool or under-fur, which keeps the cold out and the animal's body temperature in.
It was the beaver's under-fur that was most desired by fur traders and hat-makers, for this was the material which could be felted into a luxurious and fashionable hat. The fur traders judged the quality of beaver pelts according to the colour and thickness of the under-fur, classifying them as either "common" (lower quality) or "prime" (higher quality). But before the fur trader could assess a pelt's quality, the animal had to be trapped by Native hunters, skinned, stretched, and traded, and this was only the beginning of its long journey to the top of somebody's head.
Weighing between 40 and 50 pounds, Canada's national animal is one of the largest rodents in the world. Some notable features of the beaver are small muscles in its nostrils and ears, which when constricted, can keep out water, and the fur-covered lips which possess the ability to close in behind its front teeth in order to allow it to chew or cut branches under water.