An estimated 150 million people get stung by jellies each year.

How can an animal that's 95% water with no brain be so venomous?

Do all jellyfish sting?

All jellies can sting.

They have cells called nematocysts inside their tentacles that release venom when touched.

A single tentacle can contain thousands of nematocysts, making for a very potent attack.

If a small fish or other animal swims into the tentacles and get stung, the venom paralyzes them, allowing the jelly to bring the fish up to its mouth and eat it.

That venom also acts as the Jelly's main defense mechanism.

If you brush up against the tentacles, those nematocysts spring into action to protect the jelly.

Jellies have no brain and no heart, and they're technically not fish.

Although a few species can actively hunt, most jellies swim along with the current in the ocean, trailing their tentacles and waiting for something to swim into them.

Some jellies are tiny with a body the size of your thumbnail, while others, like the lion's mane jelly, can be eight feet across and have tentacles that stretch a hundred feet.

But most jellies are not dangerous to humans.

In fact, you wouldn't even feel many species stings.

But a few species are quite dangerous, so it's always a good idea to steer clear of jellies if you're not sure what you're looking at.

And whatever you do, don't pee on a jelly sting.

That's a myth and could actually do more harm than good.

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