A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
A cat rubs against people not only to be affectionate but also to mark out its territory with scent glands around its face. The tail area and paws also carry the cat's scent.
293
Blue whale arteries are large enough for humans to swim through and their hearts are the size of cars.
12
Unsinkable Sam (nickname of a German ship's cat) who served on 3 warships, one German, two British, all sank in action. The cat survived each sinking, floating away on wooden planks to rescue.
19
Cats are one of the only animals to domesticate themselves and approach humans on their own terms.
20
The difference between antlers and horns is that antlers are shed each year and are made of bone while horns are kept for life and are made of living tissue and bone with a sheath that is very similar to human finger nails.
10
If a vampire bat goes 2 days without drinking blood, they can die. However, well fed female bats will puke up blood and share it with other bats that they like in exchange for grooming.
13