Hair may increase the surface area for evaporation of sweat. Some hair follicles have a highly developed nerve network around them and provide sensory, tactile information about the environment. These are the vibrissae of the catlike animals. They are of great importance to the survival of mammals. The secondary functions of hair are now acquiring primary importance for man.
Hairstyles are used to make a statement, baldness is abhorred.
Hair color is used for identifying an individual for emigration or crime detection purposes. Even socially we use the clue of hair color to place a person within a particular faction of society. The shaft of hair comes out of the skin and has three layers. The outer colorless cuticle, the inner cortex and innermost part the medulla. Melanin, the coloring pigment and the protein keratin are in the cortex.