Yawns are more contagious among people with closer relationships.
163
Only humans shed emotional tears.
331
A human brain produces as many as 12,000 to 50,000 thoughts per day, depending on how deep a thinker a person is.
23
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
Tigers can see 6 times better at night than humans.
305
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
Mushrooms are more closely related to humans than they are to plants.
47
Enamel is hardest substance in the human body.
61