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Why do female sharks have thick skins? How many bones are in your body? What color are the eyes of a scallop? What did people do before there was toilet paper?
Find out the answer to these questions and more in this offbeat list of fun facts in science and history.
Editor’s Note: This list was originally published in 2013. It was updated with new information in March, 2016.
Female sharks have thicker skins than malesSlide 2 of 51
Female sharks have thicker skins than males
Female sharks have thicker skins than males. Scientists think it's because males have this odd tendency to bite females while mating. Despite this, sharks sometimes still gather in large quantities. In February 2016, researchers reported that more than 10,000 blacktip sharks were lurking together off the Florida coast. Understandably, though, pregnant female sharks seem to avoid males on migration routes. Who wouldn't?
Next: That's deep!Slide 3 of 51
The ocean is 8 Empire State Buildings deepSlide 4 of 51
The ocean is 8 Empire State Buildings deep
The ocean is 12,080.7 feet (3,682.2 meters) deep on average. That's about eight Empire State Buildings, stacked one on top of the other. The deepest part of the ocean, however, is about 36,200 feet down (11,030 m). That's more like 25 Empire State Buildings.
Next: A weird but handy fact . . .Slide 5 of 51
Your hand has a built in snuff boxSlide 6 of 51
Your hand has a built in snuff box
Look at the back of your hand and extend your thumb. See those two little tendons pop out and form a triangle between your wrist and your first thumb joint? Scientists call that triangle the "anatomical snuff box," because people used to have the habit of sniffing powdered tobacco from this fleshy depression.
Next: Early toiletsSlide 7 of 51
Pompeii's plumbing was ahead of its timeSlide 8 of 51