The whale and the hippopotamus have only a few hairs. In humans, hair is not found on palms of the hands or the soles of the feet. The coloration and pattern of coats in animals serve both as a camouflage for protection against enemies and as an allurement to mates. Fine and transparent, human hair is a vestige of our hairier animal forbears, that probably evolved from the scales of reptiles. The adult human body averages five million hairs, of which 100,000 to 150,000 are on the scalp.
Hair is composed of keratin, the same protein that makes up nails and the outer layer of our skin.
The part seen rising out of the skin is called hair shaft or strand. Each strand consist of three layers. The middle layer, or cortex , is the thickest. It provides strength, determines your hair color and whether your hair is straight or curly. Hair color is determined by melanin from your pigment cells.