The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
13
Yawns are more contagious among people with closer relationships.
163
Pet dogs and elephants are the only animals that seem to instinctively understand human gesture.
14
A human brain produces as many as 12,000 to 50,000 thoughts per day, depending on how deep a thinker a person is.
23
Every human spent about half an hour as a single cell.
144
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Fingers prune underwater not because of them absorbing the water or washing away the oil, but because of an evolutionary trait caused by the brain to enhance the grip of your fingers underwater.
24