It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11
In ancient Egypt, priests plucked EVERY hair from their bodies, including their eyebrows and eyelashes.
130
Every human spent about half an hour as a single cell.
144
A third of the human population sneezes when they look at the Sun. Light can signal the ocular nerve near the sinuses and triggers a sneeze.
18
Cats have a weak sense of taste. They have only 473 tastebuds, humans have 9,000.
307
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
Yawns are more contagious among people with closer relationships.
163
A man's beard grows fastest when he anticipates sex.
239