In case you weren’t already aware, the animal kingdom is a pretty intense place.

There are so many reasons for why you don’t want to mess around with mother nature.

On the other hand, we have discovered so much about the animals that inhabit the planet where we also happen to live.

Here are some of the most fascinating facts about animals.

Octopuses have three hearts. Count ’em — one, two, three! The better to love you with.

(Also, before you rush to write a comment, “octopuses” is a completely acceptable pluralization of the word “octopus.” Yes, I’m sure. Look it up.)

Flamingos’ eggs sometimes have pink yolks.

This is due to their consumption of the same algae and shrimp that turns their feathers pink.

Prairie dogs greet each other by kissing on the mouth.

If that’s not the cutest thing you’ve ever read, then there may be something wrong with you.

Sperm whales sleep vertically.

This fact is both interesting and the tiniest bit terrifying. Admit it — there’s something slightly unsettling about seeing whales like this, right?

The Pyrenean ibex is the only animal that has gone extinct twice.

The last natural-born Pyrenean ibex (named Celia) died in 2000, rendering the animal extinct. However, scientists were able to revive the ibex through cloning. A clone was born in 2003 but died after several minutes, making the Pyrenean ibex extinct for the second time.

That was kind of a bummer of a fact, but this next one is sure to cheer you up. Especially if you like Guinea pigs…

In Switzerland, it’s illegal to own a single Guinea pig.

That’s because they’re social creatures. The law dictates anyone who wants a pet Guinea pig must have at least two.

Horseshoe crab blood is blue.

Not only that, but it also has incredible antibacterial properties. A certain chemical called Coagulan is found in their blood and is used to test medical equipment and vaccines prior to human use. Horseshoe crab blood has literally saved millions of lives.

A group of jellyfish is called a smack.

Don’t you wish they had covered that in Finding Nemo?

Camels have three eyelids. (All the better to blink at you with!)

They’re not the only ones. Polar bears, seals, and aardvarks also boast a third eyelid.

In the first year of its life, a blue whale calf gains 200 pounds…each day!

Talk about a growth spurt!

This next fact will sound familiar to anyone who’s ever gone scorpion hunting (yes, that’s a thing).

Scorpions glow brightly under UV light.

Keep that in mind next time you’re walking around where scorpions might be…and you happen to have a blacklight handy.

Elephant pregnancies last for an average of 95 weeks.

That’s basically two years. Anyone who has ever been pregnant or known someone who was pregnant will sympathize with that information.

Some cats are actually allergic to humans.

So can dogs, as a matter of fact. Although most of the time, it’s actually an allergy to chemicals on humans’ skin.

Sharks have been on Earth for longer than trees have.

The earliest species we classify as a tree lived around 350 million years ago, but sharks have that beat. The earliest shark lived 400 million years ago!

Dolphins have unique names for each other.

They’ve even been observed calling and communicating with other dolphins by using their names. They’re basically having full underwater convos.

Manatee nipples are located in their armpits.

No, I don’t really know what you’re supposed to do with that information, but aren’t you glad you have it?

A group of zebras is called a dazzle.

Isn’t that perfect? It is. However, this next fact might be even more perfect.

A group of pugs is called a grumble!

A grumble!

And a group of cats is called a clowder.

If you’re talking about kittens specifically, a group is called a kindle. (Don’t try to download books to them, though.)