Your thumb is about the same size as your nose.
124
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
A third of the human population sneezes when they look at the Sun. Light can signal the ocular nerve near the sinuses and triggers a sneeze.
18
Tigers can see 6 times better at night than humans.
305
The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
13
Yawns are more contagious among people with closer relationships.
163
After age 30, the brain shrinks a quarter of a percent (0.25%) in mass each year.
139