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
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Cats recognise the voice of their owner, but never evolved to care.
22
Allegedly, Chrysippus, the Greek philosopher, died of laughter after getting his donkey drunk and watching it try to eat figs.
47
Sheep, goats, octopuses, and toads have rectangular pupils.
7
Worker bees must visit around 4,000 flowers in order to make one tablespoon of honey.
5