When a male gentoo penguin "falls in love" with a female penguin, he searches the entire beach to find the perfect pebble to present to her.
25
Jumping fleas can accelerate 50 times faster than the space shuttle.
218
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
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
Sloths take two weeks to digest their food.
243
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23