Modern humans first appeared about 200,000 years ago, but record keeping didn't begin until about 6,000 years ago. That means about 97% of human history is lost.
21
Blue eyes are a genetic mutation. Before the mutation occured, all humans had brown eyes.
89
Poor eyesight (myopia) is associated with higher IQ.
232
Human hair and fingernails continue to grow after death.
7
After age 30, the brain shrinks a quarter of a percent (0.25%) in mass each year.
139
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
A man's beard grows fastest when he anticipates sex.
239