Pentheraphobia is the persistent fear of your mother-in-law.
Amazingly, blue whales can slow their heart rate to four or five beats per minute in order to conserve oxygen during deep dives.
The male giraffe determines a female's fertility by tasting her urine. If it passes the taste test, the courtship continues.
The infinity sign is properly known as a "lemniscate."
A ten-gallon hat actually holds a little less than one gallon of water.
In addition to his work in atomic theory and physics, Albert Einstein helped patent several refrigerator designs, though none of them proved successful.