DENDROLOGY

Detailed explanation-1: -Hair (and a coat of hairs, called fur or pelage) is uniquely mammalian. No other creature possesses true hair, and at least some hair is found on all mammals at some time during their lives. Hairs grow out of pits in the skin called follicles.

Detailed explanation-2: -All mammals have hair. It is one of their defining biological characteristics. However, there are a few species with hair so reduced by evolution that they actually appear to be naked.

Detailed explanation-3: -Sea otter underfur contains from 170, 000 to 1, 000, 000 hairs per square inch, more than any other animal on Earth. A sea otter’s two-layer fur coat is better insulation than fat.