Cnidarian Fun Facts:

• The name Cnidaria comes from the Greek "Cnidos" meaning stinging nettle.
• A group of jellyfish is called a smack.
• Jellyfish can have up to 800 tentacles.
• The firing of nematocysts are the fastest reactions in the animal kingdom.
• Sea anemones are names after the Anemone Flower, and that is why the anemone is sometimes called the flower of the sea.

What type of adaptations to Cnidarians have?

Jellyfish are well-adapted to their environment with bodies that are 90% water, which helps them float around easily and not get crushed by water pressure. This adaptaion also can act as a form of camoflauge, when they look almost clear. Their stinging tentacles not only ward off predators, but also keep them warm in the freezing water so far below the surface. Their bell-like shape also helps them move through the water.

When where the first fossils of the phylum Cnidaria from?

The earliest fossil record of the Cnidarians come from about 700 million years ago.

Are Cnidarians similar to any other phylum?

The phylum most like the phylum Cnidaria is the phylum Porifera (sea sponges).

How have Cnidarians evolved over time?

Over time, Cnidarians have changed from being rooted to one place over their lifetime-like the Anthozoa class- to a type of creature that is at one point able to move around freely.

What do Cnidarians eat? What eats them?

Sea anenomes and larger jellyfish feed on small fish that pass by their stinging tentacles, but smaller jellyfish typically have a diet of plankton. The natural predators of most Cnidarians are sea turtles, fish that eat coral (ex. Parrotfish), echinoderms (ex. Starfish), and some crustaceans.

Are Cnidarians endangered?

While not many are officially endangered, the majority of Cnidarians are in some way threatened by the dustruction of coral reefs.