A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
A hedgehog's heart beats 300 times a minute on average!
14
How does a shark find fish? It can hear their hearts beating.
31
There's a rare breed of pig that looks like a sheep.
14
Iguanas have two penises!
55
Blue whale arteries are large enough for humans to swim through and their hearts are the size of cars.
12
Snails can live up to 15 years.
84