Today’s Wonder of the Day was inspired by Eric from AL. Eric Wonders, “Why do animals have tails?” Thanks for WONDERing with us, Eric!

Have you ever been playing on the playground and took a spill that put you flat on your rear end? We've all been there and done that. Sometimes it really hurts, especially when you land square on your tailbone.

Did you ever WONDER why you have a tailbone but not a tail? When you look around, tails are everywhere. They follow cats and dogs, horses and cows, and all sorts of other creatures, big and small.

So why don't humans have tails? Of course, if we did, fashion would probably look a lot different than it does today. Can you imagine what blue jeans would look like if humans had tails?

We can't know for certain why humans don't have tails. We just don't. But perhaps the answer might be as simple as this: we just don't need them!

If you look at all the animals that have tails and the ways they use them, it's clear that tails can and do serve many important purposes. Let's take a look at some animals with tails and why they're important to those animals.

For example, the humble alligator has a long, long tail. Without it, he wouldn't be able to swim as quickly as he does. If you're a swimmer, think about how much faster you might be able to go if you had legs kicking AND a tail wagging!

Tails can also help you maintain your balance…at least that's what the monkeys and squirrels in Wonderopolis tell us. Have you ever tried to run along the thin branches high up in a tree? We hope not, because you'd probably fall out of the tree! Squirrels and monkeys, though, use their tails to keep their balance and sometimes to even hold on to a branch.

Humans walk really well on just two legs, so we don't need tails to help us keep our balance. In fact, a tail might throw us off balance. Can you imagine running or walking with a tail following you around? That would take some getting used to, wouldn't it?

Some animals use their tails to communicate. Have you ever seen a dog wagging its tail in happiness? If not, grab a treat the next time you meet a dog and you'll see what we mean!

Other animals might use their tails for protection. If you ever find yourself in a facedown with a kangaroo or a crocodile, you might be worried about flying feet and snapping jaws. What you should watch out for, though, is a swinging tail that can send you reeling!

We've touched on just a few examples. Animals use their tails for all sorts of other things, including keeping warm (foxes), steering (fish), and grooming (a cow swatting flies!). Since we humans handle these things with our hands and feet, we just don't need tails!

Wonder What's Next?

Open wide! Tomorrow’s Wonder of the Day is a real mouthful!