Only 12,000 years ago there was a species closely related to modern humans called Homo floresiensis that had been living on an Indonesian Island. They used fire and rather advanced tools, yet were only about 3 feet tall and weighed around 25kg.
15
You can't tickle yourself.
29
The average sperm cell swims at 8 inches per hour.
4
Crying literally alleviates stress and uniquely allows humans to decrease feelings of anger and sadness.
24
The human body contains over a billion miles of DNA.
147
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
A human being loses an average of 40 to 100 strands of hair a day.
133
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73