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
We share 70% of our DNA with a slug.
218
The human brain is very soft, having a consistency similar to soft gelatin or firm tofu.
13
It takes approximately 12 hours for food to entirely digest.
93
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Your thumb is about the same size as your nose.
124