A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Blue whale arteries are large enough for humans to swim through and their hearts are the size of cars.
12
When a drone bee mates with a queen, its ejaculation is so powerful that it can even be heard by the human ear.
5
Parrot parents "name" their children with a signature call.
112
The cat brain weighs about 30g.
167
The CIA once spent $20 million on a cat equipped with gear to spy on the Soviets, but it was hit by a taxi.
328