字幕列表 影片播放 列印英文字幕 [Intro] You know, Squeaks and I spend a lot of time underground. And that means we've made a bunch of squirmy little friends. If you've spent any time digging in the ground, you've certainly met them, too. I'm talking about earthworms! These animals are super cool, and super hardworking, too! Let's see if we can get the dirt on these wiggly worms. First of all, even though you often find earthworms outside, where you find insects like ants and beetles, earthworms aren't insects. Can you spot the differences? Remember what makes an insect: six legs, three main body parts, and a hard exoskeleton. Our earthworm doesn't match that at all! Earthworms have smooth skin and a body made up of many small segments—it kind of looks like they're covered in a lot of little rings. And each segment has small hairs that are almost too tiny to see. And even though they're long and skinny like snakes, they're not snakes! Snakes have a skeleton, and earthworms don't. But they do have strong muscles. In order to move, the earthworm squeezes its muscles together, which makes its body thinner and longer. Then the earthworm uses those little hairs on its body to hold on to the soil around it, and pull itself forward. Have you ever seen a bird trying to pull an earthworm out of the ground? The worm can make it hard for the bird, because it can actually hang on to the dirt with those tiny little hairs! Now, just like most animals, earthworms have a front end and a back end. Up front, you'll find their mouth and a teeny tiny brain, about the size of a pinhead. But that little brain gets the job done. Earthworms are able to sense light and vibrations--so they know when to wiggle away! And when earthworms needs to wiggle away, where do they go? That's right--underground. Earthworms spend most of their time safe in underground tunnels called burrows. It not only keeps them hidden from predators, but that nice, wet soil keeps their skin moist. And that's super important. Because earthworms need to breathe just like people do, but they don't do it in the same way. They actually absorb oxygen through their skin. And in order to do that, they need to keep wet. That's why you're most likely to see earthworms when you're digging through damp soil or mud! But maybe you've seen earthworms even when you haven't been making mud pies. Have you ever seen them hanging around on the sidewalk after a rainstorm? A rainy day for an earthworm is a perfect moving day. Sometimes one area becomes too crowded with earthworms, so they need to find a new home. But they need to keep their skin moist while they're out moving around. So earthworms use those soggy days to come out and look for a new place to live. Then back into the ground they go! But the dirt isn't just a safe place for worms to hide, it's also their food. As an earthworm moves through the soil, it's also is eating the dirt! Earthworms get their nutrients from dead and decaying parts of plants, like leaves and roots, that are in the soil. And earthworms are hungry. They can eat half their bodyweight in just one day! But maybe the coolest thing about earthworms? As they munch through the soil, they actually make the soil better for the rest of us. How do they do that? Well, the tiny tunnels that earthworms make as they wiggle through the dirt help bring water and air deep into the ground. And that makes it easier for other living things -- like plants and fungus -- to live in it. Plus, as earthworms break down all of those dead plant parts, they help spread around all of the nutrients that are in them, to make food for new things to grow. Some people even keep earthworms in their garden on purpose! They feed the earthworms things like banana peels and apple cores. Then, the worms turn those scraps into compost -- a rich, smelly, nutritious kind of plant food made from … dead plants! To you, it might just look like trash, but to an earthworm? It's treasure! Healthy earthworms means healthy soil! And healthy soil means healthy people--because we need it to grow plants for our own food! So the next time you come across an earthworm--thank them! They're hard at work helping flowers, trees, grass, and plants grow. And thanks to you for joining us here at SciShow Kids! If there's anything that you'd like to learn more about, ask your parents to help you email us at kids@thescishow.com, and we'll see you next time!