Hair 102: Why do we have hair?

Hair is more than just a pretty cover up. It serves many biological
functions and actually covers most of your body (often growing in
places you’d rather it didn’t).
The functions of hair (both on your head and elsewhere on your
body) are that
 It protects your head.
 It keeps you warm in the winter and cool in the summer.
 It protects you against sunburn.
 It has nerve endings that serve to make a scalp massage feel
good, yet tell you when a mosquito has landed on your arm to
bite you.
Hair and ethnicity: How race
impacts hair
What your hair looks like is directly related to the genes you
received from your parents. There are some hair generalities
related to different racial groups, although your individual hair
traits will vary. Many people’s gene pool today is pretty diverse!
(See Chapter 2 for much more about hair and ethnicity.)
However, the following generalities apply:
 Although it appears that many Caucasians have thinner hair
than other ethnicities, Caucasians actually have the highest
number of hairs on their heads, an average of two hundred
hairs per square centimeter.
 Asians have the thickest and coarsest hair, which makes it
appear as though they have more hairs on their head. They
average a hundred and fifty hairs per square centimeter.
 African Americans have the thinnest and the finest hair, but
because it mats together more than Caucasian or Asian hair, it
appears thicker. African hair averages a hundred and thirty
hairs per square centimeter.