Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
Yawns are more contagious among people with closer relationships.
163
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
Poor eyesight (myopia) is associated with higher IQ.
232
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
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
The average person's skin weighs twice as much as their brain.
131