Some hairy facts from Encarta’s article on hair:
All mammals have hair
Hair is called fur when individual hairs are fine and close together. It’s called wool when it’s soft, kinked, and matted together. If hair is coarse and stiff, it’s called bristles. And pointy bristles are called quills.
Hair is a kind of protein known as keratin. It doesn’t have blood vessels or nerves, which is why haircuts aren’t a painful and messy experience.
Each hair follicle has its own tiny muscle that can help the hair stand up.
Hair grows faster when it’s short than when it’s long. When it’s short, it grows about ¾ inch a month. When it’s more than a foot long, it grows about half that fast.
Young women from the ages of 16-24 enjoy the fastest hair growth.
http://encarta.msn.com/encnet/features/Columns/?Article=questioneyebrows