With the Kids: Simple jellyfish are amazing creatures

No eyes, no hearts, no brains, but gelatinous,

jiggling jellyfish are wondrous creatures.

There are things living in the ocean that look like they fell out of your sandwich. If you enjoy visiting beaches or exploring tide pools, chances are good that you’ve seen them. Perhaps their slow pulsing movement captivated you as they floated past your kayak. Or maybe you poked at the strange, Jell-O-like blobs they become when washed up on the shore. But what are these amazing animals?

Jellyfish are found in seas all around the world and have lived on Earth since before dinosaurs. They certainly look like jelly, but those squishy creatures are animals.


Don’t confuse them with fish, though — soft jellies have no bones, teeth or hard parts of any kind. Jellyfish also have no eyes, brain or heart. These ancient creatures are made mostly of water (98 percent) and have fairly simple bodies. A single opening even serves as both a mouth and the exit point for waste.

As they grow through their life cycles, though, jellyfish might remind you of frogs or butterflies because they change shape. They spend part of their lives in the form of tiny tubes, or polyps, stuck to pilings or rocks on the ocean floor. Then, the polyps transform into many of the familiar, bell-shaped adults (medusae) we see drifting near the surface.


Jellyfish contract or pulse their bells to help them move up and down in the water. Since these slowpokes can’t swim faster than ocean currents, they belong to the group of floating living things called plankton. Plankton include plant-like organisms so small that you need a microscope to see them, and the tiny baby form, or larvae, of all kinds of familiar sea creatures, such as crabs, octopuses, sea urchins and shrimp. Together, jellies and other plankton are a key food source for lots of marine life.

Sea turtles especially like to chomp on jellyfish. But when plastic bags from our trash wind up in the ocean, they float and look much like jellyfish. When sea turtles and other animals eat these bags, they can become very sick or die. We can help protect both jellies and sea turtles by recycling bags, properly disposing of them and switching to reusable fabric tote bags for groceries.


Like sea anemones, jellies go fishing with a mop of stingers. The tentacles that hang down and drift behind their bodies are loaded with tiny stinging cells called nematocysts. When small fish, zooplankton, krill and other little animals swim too close and brush against the tentacles, those nematocysts fire miniature harpoons of venom that paralyze the prey.

While the sting of some kinds of jellyfish species can be very dangerous to humans, most cause us minor pain and irritation or are harmless. Watch out for those beach blobs, though — dead jellyfish nematocysts can still fire.

Hands-off is the best approach to jellies, but they are beautiful to watch. These see-through animals come in all sorts of colors and sizes, from smaller than a dime to larger than a person.

Here in Puget Sound, we can find several interesting species. The egg yolk jelly earns its common name with a yellowy-orange center surrounded by a clear to whitish blob ring. Moon jellies are otherworldly looking … almost completely transparent except for a wispy white outline and brighter white four-leaf clover shape in the middle of their bells that marks their reproductive parts. Sometimes button-sized and sometimes as big as dessert plates, they are mesmerizing in motion.

If you want to see really big stingers, watch for boldly colored lion’s mane jellies. These rich orange, crimson or plum jellyfish float in our waters and can grow to be nearly 8 feet across with tentacles stretching almost 100 feet long. Their thick “mane” of reddish-gold tentacles seems almost lion-worthy and makes them easy to spot.

Scientists also have their eyes on jellies. Occasionally, large numbers of them show up in thick “blooms,” temporarily turning the ocean into jellyfish soup. Since jellyfish are able to survive in degraded ocean conditions for short periods of time, unusually large blooms might offer clues to ocean habitat health.

Mysterious, quiet and colorful, these squishy animals hold secrets to life in the deep. The transparent shape-changing beauties are enchanting to watch.