Technology
How Do Jellyfish Sting?
In this episode of Curious Kids Every Day, Josh explores the fascinating world of jellyfish and their unique stinging mechanism. Listeners learn how jellyfish use specialized cells to deliver venom an...
How Do Jellyfish Sting?
Technology •
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Interactive Transcript
Speaker A
Hi, welcome to Curious Kids Every Day. I'm Josh. How are you doing today? It's so good to hear from you. Hey, have you ever been to the beach? My family went last year and we had so much fun. But while we were there, something really strange happened. One morning we went out to play on the beach, and suddenly we saw hundreds of little jellyfish just lying on the sand. The waves had brought them all in the night before. Just these tiny little jellyfish. They were everywhere. And you know what we had to tell our kids? Don't step on them, because guess what happen? You step on a jellyfish. Yep. You get stung. Have you ever been stung by a jellyfish? I haven't, but I've heard it really hurts. Have you ever wondered how a jellyfish stings or why it stings or what a jellyfish even is? It doesn't really look like a fish or jelly. Okay, I guess it does look kind of like jelly. But let's figure it all out today. Jellyfish are some of the strangest animals in the ocean. First of all, they don't have bones or a brain or even a heart. They're mostly made of water and soft tissue, which makes them look kind of like wobbly blobs floating through the sea. But don't let all that wobbliness fool you. Jellyfish are actually skilled hunters. So how do they sting? The stinging comes from special cells in their tentacles called cnidocytes. Can you say cnidocytes? Inside these cells are tiny capsules called nematocysts. Can you say nematocysts? You can think of a nematocyst like a microscopic harpoon or dart. Each one has a coiled up thread that's ready to fire at lightning speed when something brushes against the jellyfish's tentacle, like a small fish, or maybe even your leg. When you're at the be, the capsule explodes, shooting the thread outward. The thread can pierce the skin of the animal or person that touched it, and it delivers venom. The venom is what causes pain, redness, and sometimes swelling if a person gets stung. But for the tiny fish or plankton that jellyfish hunt, the venom works even more powerfully. It paralyzes or kills the prey, making it easy for the jellyfish to pull the meal into its mouth, which is right in the center of its body. Now, a single jellyfish can have thousands of these stinging cells all over its tentacles. And each nematocyst works only once. So once it fires, it can't reload. But that's no problem for the jellyfish because they have so many, they can just sting over and over again. Now you might be wondering, why do jellyfish sting people? Well, they don' want to. Humans aren't food for jellyfish. But their stinging cells don't have the eyes or the brain to decide when to sting. They just react when something touches them. So if you brush up against the jellyfish in the ocean, or maybe step on one that's washed up some sand, those cells might still fire and sting you even if the jellyfish didn't want to. If a jellyfish could talk, I'm sure it would probably say, oh no, I didn't mean to sting you, human. I'm sorry. Aw, I can' believe I wasted a nematocyst on you. Not all jellyfish stings are equally dangerous. Some are mild and just feel like a painful rash. While others can be very serious. The box jellyfish found in Australia is one of the most venomous animals in the world. Its sting can actually be deadly. But most jellyfish you might see at the beach aren't that harmful. It just hurts for a while and then the pain goes away. Still, it's smart to be careful and avoid touching them. So to sum it all up, a jellyfish stings by firing tiny venom filled harpoons called nematocysts. And these are hidden inside special cells on their tentacles. They use this to catch prey and defend themselves. To us it feels painful, but to them it's just part of surviving in the ocean. Okay, let's have a quick quiz. What are the special stinging cells in jellyfish tentacles called? They're called cnidocytes. Okay, so then inside each stinging cell, what is the thing that acts like a tiny harpoon? Right. That's a nematocyst. What do jellyfish use their stings for? To catch prey and defend themselves. Let's play a couple rounds of true or false. True or false? Jellyfish have brains. That is false. True or false. A jellyfish can sting even after it's washed up on the beach. That's true. That's why when we were at the beach last year, we had to tell our kids, don't step on those jellyfish. Would you rather have a jellyfish's soft body or a crab's hard shell? It would be cool to be able to just kind of float through the water the way a jellyfish does. I think I'll go with the jellyfish's soft body. Alright, I'm gonna name a creature and you tell me if it stings or not. Are you ready? Do bees sting? Oh yeah, bees sting for sure. What about an octopus? Does an octopus sting? No, it doesn't sting. What about a scorpion? Does a scorpion sting? Yes, it stings. How about a starfish? No, it doesn't sting. What about an ant? Some ants sting, so yeah. How about a seahorse? Nope, no stinger there. And finally, a jellyfish. Do jellyfish sting? Yep. That's the whole point of our episode today. Well, now we know that jellyfish sting with special cells that shoot venom filled harpoons helping them catch their prey. They don't mean to hurt people, but their stingers don't know the difference between a fish and a human leg. That's why we have to be careful when we're at the beach. And if you see one washed up on the beach, don't try to make a peanut butter and jellyfish sandwich either, okay? Trust me, it's not good. What kind of question do you think we'll ask tomorrow on Curious Kids every day? I can't wait to find out. So until then, keep asking questions and stay Curious kids. And for all the grown ups listening, don't forget that the Curious Kids club starts soon. Go to support curiouskids.com for more information and please visit curiouskids everyday.com to get a free printable with activity ideas that don't involve screens. Those are the best kinds of adventures to have. That's curious kids everyday.com See you tomorrow.