A duck's quack doesn't echo, and no one knows why.
173
Chained dogs are 3 times more likely to bite than unchained dogs.
34
Some ribbon worms will eat themselves if they can't find any food.
-33
The average housefly weighs 10 to 15 millionths of a pound.
33
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
The two oldest cats on record lived to 38 and 34 years old, both were owned by the same owner and lived off a diet of bacon, eggs, broccoli and coffee.
12
Giant Anteaters' front legs look like a panda.
48
Large kangaroos can cover more than 30 feet with each jump!
19