Man is a mammal and hair is a special feature in all mammals. Each one of us possesses one to two lakh hairs on our heads, which grow at the rate of half an inch per month. In adults, hairs are present on the head, in the armpits and in the pubic area. The males also have them on the chest and the face. The visible part of the hair is called the ‘shaft’. It consists of three layers: cuticle, cortex arid medulla. The invisible part is called the ‘root’. The entire root lies inside a ‘hair follicle’, which is a tiny sac below the skin’s surface. At the bottom of the follicle, there is a tiny bump called papilla. This is from where new hair grows rapidly. It contains an artery that nourishes the root of the hair. Hair grows by forming new cells at the base of the root. As the new cells form around the papillae, the old ones are pushed out and die away. The new cells force the dead cell’s rod out of the follicle. In this way, the hair grows and becomes a part of the shaft. Hair go on growing even after a person dies because the cells of the body go on working until they have exhausted their fuel supply. As long as the cells keep working after death, hair will continue to grow. When the fuel in the cells is over, they die away and the hair stops growing. Hair is very important for us. It provides warmth, protect the skin and responds to touch. Hair retains warmth by trapping a layer of air next to the skin.