What are the four main functions of hair?

Answer 1

First, it slows the exchange of heat with the environment (insulation). Second, specialized hairs (whiskers or "vibrissae") have a sensory function, letting the owner know when it is in contact with an object in its external environment. These hairs are often richly innervated and well-supplied with muscles that control their position. Third, through their color and pattern, hairs affect the appearance of a mammal. They may serve to camouflage, to announce the presence of especially good defense systems or to communicate social information. Fourth, hair provides some protection, either simply by providing an additional protective layer or by taking on the form of dangerous spines that deter predators.