There are approximately three chickens for every human on Earth.
13
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
The Basenji dog is the only dog that is not able to bark.
4
Sheep, goats, octopuses, and toads have rectangular pupils.
7
Some older/less efficient worker termites will develop 'backpacks' of toxic chemicals that explode when the termite is threatened. They are essentially used as suicide bombers when the colony is being attacked.
8
Cows as they are today never existed in the wild and were domesticated from aurochs some 10,500 years ago.
6
The oldest creature ever found was Ming the clam at an admirable 507 years old.
16