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
The human brain is more active during sleep than during the day.
28
The human body contains over a billion miles of DNA.
147
After age 30, the brain shrinks a quarter of a percent (0.25%) in mass each year.
139
Mushrooms are more closely related to humans than they are to plants.
47
One human hair can support 3 ounces.
191
The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
13
Pain occurs when sounds are above 130 db.
124