Only humans shed emotional tears.
331
It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Our brains have a negativity bias and will remember bad memories more than good ones.
15
A man's beard grows fastest when he anticipates sex.
239
The human brain doesn't stop developing until about 25 years old.
102
When you are looking at someone you love, your pupils dilate, they do the same when you are looking at someone you hate.
1k
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197