Anemones

Often found in clumps on rocks and pier pilings, Anemones can be difficult to spot if you don’t know what you are looking for. They are frequently mistaken for plants because they are stuck in place to a rock and some species are green. However, they are animals. Anemones are marine invertebrates, animals that live in the sea and do not have a backbone.

Here are some Aggregating Anemones. The blue arrow points to an open one. The red arrow points to one that is closed. Some anemones will cover the outside of their bodies with shells and sand for protection.

The stinging cells, or nematocysts, are like miniature harpoons that fire when something touches them

Anemones are closely related to jellyfish and coral. All of these animals share the common trait of having stinging cells called, nematocysts (ni-mat-uh-sists). The strength of these stinging cells depend on the species. The sting of the Lion’s Mane Jellyfish is very painful whereas you may not even feel the sting of a Moon Jelly. The “sting” of most anemones makes their tentacles feel sticky when you touch them. To a small fish or crab, however, the sting could be fatal.

Anemones are generally stuck in one place their whole lives. Because of this, they are opportunistic eaters. They will eat whatever floats by them that they can catch. Mostly they eat plankton (small drifting animals, algae, and bacteria), small fish, crabs, snails. Anemones only have one opening for their digestive system; so after they eat an digest their food, the leftover waste exits the same way the food entered.

Some anemones get food through a relationship with a type of single-celled algae called zooxanthellae. Often seen in the large solitary anemones, this partnership makes anemones appear bright green. The algae uses sunlight to produce food that the anemone can use. In turn, the anemone gives the algae a safe home in the sunlight.

Even though an anemone’s stinging cells offer great protection, they are preyed upon by a number of animals. Some sea slugs, fish, sea stars and sea turtles are able to overcome the sting to have some anemone for lunch.