This illustration from a book published in 1904 shows a few of the many different kinds of sea anemones. By Ernst Haeckel
Although they look like underwater plants, sea anemones are actually animals that live in the oceans. Sea anemones are invertebrates, which means they do not have skeletons inside their bodies. They grow long, soft, tube-like bodies with one or two rings of tentacles at one end. Their bodies are usually between 0.5 inches and 20 inches in diameter, although in tropical areas sea anemones can grow to six feet across.
Sea anemones almost always attach themselves to the sea floor and wait for ocean currents to bring small animals to them. Once the animal is within reach, an anemone uses its tentacles to sting, poison, or stun its prey and then eats it.
Sea anemones often live near land: some anemones live in the intertidal zone, which means they are underwater when the tide is high and exposed to the air when the tide is low. Other anemones live below the low tide line, which means they are underwater all of the time.
Sea anemones can be found all along the East and West Coasts of North America. The American Tube-Dwelling Anemone, which lives along the coast between North Carolina and Florida, builds and lives in a hard protective tube made of sand glued together with mucus. When it feels threatened the anemone hides in its tube. The Pale Anemone, which is found in southern Florida, has no protective structure. Pale anemones live in colonies with other anemones, usually on the roots of mangrove trees.
This tube-dwelling anemone was photographed off the coast of South Africa. By Seascapeza
This pale anemone has its tentacles extended as it waits for food to come within reach. By Haplochromis
The above link plus:
Kaplan, Eugene H. A Field Guide to Southeastern and Caribbean Seashores. Houghton Mifflin Company: Boston, 1988. Pp. 200-219.
Love, Carrie and Caroline Stamps, ed. Animals: A Children’s Encyclopedia. New York: DK Publishing, 2008. Pp. 230-231.