A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Lobsters have blue blood.
476
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
Mahatma Gandhi used to travel with his goat so that he could have fresh milk.
11
Sergeant Stubby was the only war dog to be promoted to sergeant through combat in WWI. He saved his regiment from surprise mustard gas attacks, found and comforted the wounded, and even once caught a German spy by the seat of his pants, holding him there until American Soldiers found him.
16
The Basenji dog is the only dog that is not able to bark.
4
The male seahorse carries babies and 'gives birth' to them instead of the female.
7
An average cat has 1-8 kittens per litter and can have 2-3 litters per year. During her productive life, one female cat could have more than 100 kittens. A single pair of cats and their kittens can produce as many as 420,000 kittens in just 7 years.
10