Man is a mammal and all mammals have some hair. In the case of other creatures, we can see how having hair is useful. Its chief value is that it holds the heat of the body.
Hair protects tropical animals from direct sunlight. A long mane can protect an animal’s neck. The hair of a porcupine helps it fight its enemies. But why do human beings have hair?
To begin with, an infant at birth is covered with a fine down. When a child is in the process of becoming an adult, this hair coat is transformed into an adult coat. And the development of this adult hair coat is regulated by certain glands containing special hormones.
In the male, these hormones cause hair to grow on the body and face, and hold back the growth of hair on the head. In the female, the hormones act in just the opposite way. There is less hair on the body and face, more hair growing on the head.
These differences iR the male and female hair growth are called “secondary sex characteristics”. That is, they are another way of setting the two sexes apart. The man’s beard not only indicates he is a man, but is supposed to give the male an appearance of power and dignity.
Charles Darwin, a famous nineteenth-century naturalist, that as man developed, he needed the fine hairs of the body to help drain off perspiration and rainwater. The hairs that appear in certain parts of the body, such as the eyebrows, lashes, and the hairs in the ears and nose, help guard these body cavities against dust and insects.
Can hair grow 1 inch a month?
It’s impossible to say exactly how fast your hair grows everyone is different! but on average, hair grows about half an inch over the course of a month.