A jellyfish has no brain, but its tentacles are covered in amazing cells. Each one hides a tiny coiled thread that can shoot out faster than you can blink!
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Jellyfish tentacles are covered with thousands of stinging cells. Scientists call them cnidocytes (say "NYE-doh-sites").
Scroll up to the 3D model and press Cut it open to see the coiled thread inside.
When something brushes the trigger hair, the capsule pops open and the thread shoots out. The thread can carry a little bit of venom to stun tiny prey, like small shrimp or fish, so the jellyfish can eat them.
Each stinging cell can only fire once. Then the jellyfish grows a new one to take its place.
Press Fire! on the 3D model to watch the thread shoot out.
Firing a stinging cell is one of the fastest movements in the whole animal world. It happens far faster than a blink!
Jellyfish do not have a brain. They have a simple web of nerve cells called a nerve net. The stinging cells do their job right where they are, out on the tentacles.
Sea anemones and corals are cousins of jellyfish, and they have stinging cells too.
Even a jellyfish washed up on the beach can still have stinging cells that work. So if you see one, look with your eyes, not your hands. Tell a grown-up and give it some space!
By Deep Look. Good for older kids.
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