The average sperm cell swims at 8 inches per hour.
76
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
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
Your heart will pump about 212 million liters in its lifetime.
26
Your thumb is about the same size as your nose.
124
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
An Indian man known as "Snake Manu" can put small snakes, including deadly cobras, into his mouth and pass them out through his nose.
59
The human brain doesn't stop developing until about 25 years old.
102