Getting Wild with the Sea Anemone


PHOTO: Nemo's Great Uncle/Flickr
PHOTO: Nemo’s Great Uncle/Flickr

Sea anemones are invertebrates which live in coastal saltwater and tropical regions. There are more than 1,000 different kinds of sea anemones. Most sea anemones are three to 12 inches in diameter, but some can grow to be six feet in diameter and can live to be more than 80 years old! They look like underwater flowers with waving tentacles when they are open, and when they are closed they look like a compact jelly blob. Sea anemones come in a variety of colors, and some are a rainbow pattern.

Sea anemones are carnivores: they eat fish, zooplankton, sea worms, mussels and crustaceans. To catch their food, they wait until an animal swims into their tentacles, which release poison to paralyze their prey. Sea anemones are capable of eating animals that are slightly larger than they are. They swallow their prey whole and continue to sting it even after it is swallowed.

Sea anemones have one foot and use it to attach themselves to rocks.

PHOTO: Samuel Chow/Flickr
PHOTO: Samuel Chow/Flickr

Fun Facts:

  • Sea anemones and algae help each other in a reciprocal relationship. Sea anemones provide safety for the algae, and in exchange, the algae give them oxygen and sugar.
  • Clown fish hide in the tentacles of sea anemones without getting stung. The fish cover themselves in their own mucus so that the anemones don’t recognize the clown fish as food.
  • Sea anemones do not have brains. Instead, they have a complex nervous system that connects to their muscles and stomach.
  • In 2014, scientists discovered that sea anemones’ genes are half plant and half animal! They depend on a plant-like process to regulate the animal genes’ activity.

Glossary of Terms:

Invertebrates: An animal lacking a backbone or a spinal column.

Crustaceans: Underwater animals with a shell, for example crabs and shrimp.

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