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Moon Jellies

Instead of vying for cart space in the grocery store aisles, just plaster your arms with sticky tape and drift along the shelves to pick up what you need. It works for moon jellies.

A moon jelly’s bell-shaped upper body is coated with gummy mucus. Brine shrimp, fish larvae and other planktonic animals get stuck in the mucus, then slide down the bell to four long, frilly oral arms that move the food into the jelly’s mouth. When you visit Waters of the World, look into a jelly’s glowing bell to watch not one, but four U-shaped stomachs digesting the food.

Named for their ghostly, translucent bells, moon jellies (Aurelia aurita) are abundant in temperate and tropical waters worldwide. Their delicate bodies pulse and drift with the effortless grace of a ballerina. The moon jelly’s short tentacles are armed with stinging cells, called “nematocysts,” but the sting lacks the toxic, painful punch of other jellies. Most people would not even notice its effect. Although they’re 95 percent water, moon jellies are the main course for leatherback sea turtles and other marine creatures. Thousands of animals die annually from mistakenly swallowing drifting plastic bags, which resemble the gelatinous jellies.

Scientists have broadly researched the moon jelly’s life cycle. A male releases sperm in the water to fertilize the female’s eggs, which resemble purple popcorn. After hatching, the larvae attach to a solid surface and develop into polyps. For years, even decades, the polyp can alternate between feeding, budding into more polyps and spreading. At some point, it produces stacked cuplike sections that launch off as young adults. These finally change into the familiar bell-shaped adults we recognize. What an incredible process for such a simple organism.


Don't miss the Jellies special exhibit. Discover how these animals, which are 95 percent water, survive and thrive in the world’s oceans. Find out more.

Did you know?

Did you know it takes the moon jellies about eight hours to digest a meal? Find out more.

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