字幕表 動画を再生する 英語字幕をプリント [BEEPING] Hi, it's Doug. You can see here I have a turtle. There are different kinds of turtles. This kind is called a tortoise, and you might have heard of them. Tortoises are turtles that live on dry land. They don't need to be in water. In fact, they don't like to be in water. Now, why do I have a turtle with me? Well, this is actually my pet. It's my pet tortoise. And I thought it'd be fun to get it out, because someone named Samaliya has a question for us about turtles. Let's give her a call now. [BEEPING] Hi Doug. I have a question for you. Hey Samaliya. Could a turtle live outside its shell? That's a great question, Samaliya. Let me show you something. You know how turtles have this shell that they can hide in. They can pull their head in if they want to, even their legs and tail. But could a turtle come out of its shell completely, like crawl out of it and leave its shell behind? Like, you might wonder, maybe a turtle is like a hermit crab. Hermit crabs are these creatures that live in shells, but the shell isn't part of their body. They can come out of their shells completely. Could a turtle do that, too? Well, let's look at a picture of a turtle up close. Does this give us any ideas? If you want to pause the video to take a longer look at it, now would be a good time. OK, you ready? If you've ever touched a turtle shell, then you know it's very hard. It feels similar to how a fingernail feels. It feels like a similar material. And the top part here, what looks like a pattern or design, I learned once is actually separate pieces, almost like tiles. Now, none of this really helps us figure out if a turtle can come out of its shell, though. But look at this photo again. This here-- this is the turtle's skin, and these parts on top and bottom are the shell. Now right here, maybe you noticed that there's no space between the turtle's skin and its shell. It's all connected. A turtle's skin is connected to its shell. So I have to say, it seems like a turtle's shell is probably part of its body. I'm thinking the answer to the question is no, a turtle can't come out of its shell the way a hermit crab can. But it'd be great to be totally sure. Now, how can we be totally sure? Is there anything else we could look at? Well, what we really need is to be able to look inside the shell. And for that, we need to see a turtle's bones. That's what you see here. This is a real picture of a turtle skeleton. We can see turtles do have bones, just like we do. You see here's the skull, here's the neck bones, leg bones. But now, what about the shell? Let's get a closer look at that. Again, if you want to pause the video to look, now would be a good time. OK, you ready? Now maybe you saw what I saw, that the shell itself, on the inside, is white. You see that there? It looks like it's made of bone. In fact, if we flip a turtle skeleton over so that we can look at the turtle from below, we can see its backbone here. Now, look really closely. It looks like the shell is just part of the backbone. Can you see that? Interesting. Now, it turns out sometimes scientists find fossils of turtle bones. I'm talking about bones from turtles that lived long, long ago. This is a turtle fossil right here. A really long time ago, it seems that turtles didn't have the complete shells that they have today. Instead, a long time ago, it was just really long backbones. So maybe, over time, scientists think, turtle backbones have gotten bigger and bigger, to the point where the backbone now forms a complete shell on the turtle's back. So can a turtle live outside its shell? Well, you've seen all the clues. The answer is no, a turtle's shell is part of its body. When we look on the inside at the turtle's skeleton, we can see that the shell is part of the turtle's backbone. And when we look at turtle fossils, we can see that back in time, it definitely was just the backbone. So thanks, Samaliya, for asking that question. Now, for next week, I reached into my question jar, and I found three questions that were submitted that I'm thinking about answering next. When this video is done playing, you'll get to vote on one. You can choose from-- why is the sky blue? I found this rock with all these holes in it. How did they get there? Or, why can't everyone curl their tongues? Submit your vote when the video's over. I want to hear from all of you watching. Remember, there are mysteries all around you. Have fun and stay curious.