Blue whale arteries are large enough for humans to swim through and their hearts are the size of cars.
12
There is a sea snail that wears a suit of iron plated armor. It is the only known animal to use iron sulphide as skeletal material.
9
The Basenji dog is the only dog that is not able to bark.
4
The ancestor of all domestic cats is the African Wild Cat which still exists today.
12
Cows as they are today never existed in the wild and were domesticated from aurochs some 10,500 years ago.
6
A zoo in China gave a gay penguin couple the opportunity to raise a chick.
11