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
The colossal squid has the largest eyes in the world.
4
Blue whale arteries are large enough for humans to swim through and their hearts are the size of cars.
12
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