Scyphozoa

Scyphozoa: The True Jellyfish

Scyphozoa are a special group of animals called true jellyfish. They live only in the sea, not in rivers or lakes. These jellyfish have been swimming in the ocean for a very long time, since the Cambrian period, which was millions of years ago.

The name Scyphozoa comes from an ancient Greek word, skyphos, meaning a kind of drinking cup. This is because many of these jellyfish have a cup-like shape. Scientists love to study them because they help us learn about life in the ocean and how animals have changed over time.

Most true jellyfish have two main stages in their life. One stage is called a medusa, which floats freely in the water, especially in warm weather. The other stage is a polyp, a smaller form that lives on the ocean floor and helps make new jellyfish.

These jellyfish can be small, about the size of your hand, or very large, like the Cyanea capillata, which can be as wide as a big table! They eat tiny sea animals and plants by using special stinging cells on their tentacles. All Scyphozoa live only in the ocean, never on land.

True jellyfish have a soft, gel-like material inside that helps them stay up in the water. They move by squeezing and relaxing muscles around the edges of their bodies. Some even have tiny mouths on their arms to help them eat!