1. Octopuses have three hearts. One pumps blood around the body, while the other two pump it to the gills. Oh, and that blood is blue, thanks to high copper levels!

2. Owls don’t have eyeballs. They have eye tubes.

3. Polar bears have black skin, which helps them absorb heat from the sun to stay warm in an Arctic climate, and it likely protects the bears from harmful UV rays.

4. A human brain operates on about 15 watts.

5. Butterflies can taste with their feet, using something called chemoreceptors to help them identify plants. Females select the correct leaf on which to lay eggs by “drumming” it with their feet to release juices.

6. Animals with smaller bodies and faster metabolism see in slow motion.

7. Dogs’ sense of smell is about 100,000 times stronger than humans’, but they have just one-sixth our number of taste buds.

8. Reindeer eyeballs turn blue in winter to help them see at lower light levels. (They’re golden-colored in summer.) No other mammals are known to have this ability.

9. A single strand of spider silk is thinner than a human hair but also five times stronger than steel of the same width. A rope just 2 inches thick could reportedly stop a Boeing 747.

10. The claws of a mantis shrimp can accelerate as quickly as a .22-caliber bullet. Scientists must keep them in thick plastic tanks because their punches can break glass.

11. A sea lion is the first nonhuman mammal with a proven ability to keep a beat. Scientists trained a female sea lion named Ronan to do it, and she then showed she could transfer that skill to a song with a different beat that she had not heard before.

12. Squirrels can’t burp or vomit, nor can any other rodent, which is why rat poison is so effective; other mammals tend to expel any toxic substance they ingest.

13. The extinct colossus penguin stood as tall as LeBron James.

14. Honeybees can flap their wings 200 times every second.

15. A type of “immortal” jellyfish can cheat death indefinitely.

16. Cats and horses are highly susceptible to black widow venom, but dogs are relatively resistant. Sheep and rabbits are apparently immune.

17. Sharks kill fewer than 10 people per year. Humans kill about 100 million sharks per year. They should be much more scared of us than we are of them.

18. Tardigrades are extremely durable microscopic animals that exist all over Earth. They can survive any of the following: 300 degrees Fahrenheit (149 Celsius), -458 degrees F (-272 C), the vacuum of space, pressure six times stronger than the ocean floor, and more than a decade without food.