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Moon jelly

Learn more about these ancient drifters of the sea!

Jellies have been around for hundreds of millions of years—since before dinosaurs roamed the earth. They’re members of the phylum cnidaria, pronounced NYE-daria, from the Greek word for “stinging nettle.” This group of invertebrates is made up of animals that have stinging capsules in the tentacles surrounding their mouths. Puget Sound is home to well over 340 species of cnidarians, including the moon jellies at the Seattle Aquarium.

At the Aquarium

About those stings

All jellies carry a sting—it’s what defines them as cnidarians. But the severity of that sting varies greatly from species to species. For instance, the sting of a box jelly, found in the waters around eastern Australia, can kill an adult human in less than three minutes! Lucky for us, the jellies found in Puget Sound aren’t very dangerous—but their stings can still cause plenty of pain and irritation. It’s best to stay on the safe side and not touch them. Be careful: even dead jellies that have washed up on the beach can sting!

Quick Facts

Jellies have been around since before dinosaurs roamed the earth!

Quick Facts

Jellies are the largest form of plankton.

Quick Facts

These invertebrates have stinging capsules in the tentacles surrounding their mouths.

Explore More Invertebrates

An adult sea otter at the Seattle Aquarium looking upwards with its front paws resting on its front.

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Sea otter at the Seattle Aquarium laying on its back, raising its head and front paws.

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