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 average sperm cell swims at 8 inches per hour.
4
Women have about four times as many foot problems as men; lifelong patterns of wearing high heels often are the culprit.
111
In 30 minutes, the average body gives off enough heat (combined) to bring a half gallon of water to boil.
198
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
A person can live without food for about a month, but only about a week without water.
156
The human body contains over a billion miles of DNA.
147