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Stunning sea flower, or deadly animal? One scientist unlocks the secrets of a strange and beautiful sea creature.


Estefania Rodriguez is standing on a boat in the Southern Ocean off the coast of Antarctica. Even though it's summer, temperatures hover around -4[degrees] Celsius (25[degrees]F). Rodriguez and other scientists have been waiting for two hours for the crew to haul up nets full of animals from the ocean floor. Once the nets are emptied, Rodriguez reaches for sea anemones (uh-NEM-uhnees), relatives of jellyfish and coral. Now the wait is worth it!

Each year, Rodriguez scours the seafloor for sea anemones. She is one of only five experts in the world studying these creatures, which scientists know little about. "For me, they are the most important thing in this world, apart from my family," says Rodriguez. She studies invertebrates, or animals without backbones, at the American Museum of Natural History in New York City.

More Than Meets the Eye

At first glance, sea anemones look like colorful, exotic flowers that sway with the current on the seafloor. But sea anemones are actually animals--and, in fact, they're deadly hunters.

Many sea anemones spend most of their lives anchored to one spot. Their bodies look like a hollow sack with an opening on top. The opening, or mouth, has tentacles surrounding it. Tentacles are narrow, flexible body parts--often used for feeling or grasping--that extend from the bodies of some animals and plants. On anemones, each tentacle is tipped with stinging capsules, which turn the tentacle into a weapon.

"These capsules contain darts and are filled with toxins," Rodriguez says. Toxins are natural poisons that can be used for protection or to kill or disable prey. "And they can be very nasty," Rodriguez notes.

Anemones swipe passing fish or shrimp with their tentacles. The prey are killed or stunned. Then they become the anemones' next meal.

Fortunately, sea anenomes are more dangerous to small sea life than to people. "Usually, if you touch sea anemones with the palm of your hand, you don't feel pain," says Rodriguez.

More to Discover

On deck, Rodriguez collects the sea anemones from the haul. She takes them back to the museum for further study.

Every time Rodriguez gathers sea anemones, she discovers something new. She has found six new species and has identified surprising anemone behaviors (see "Making Friends," right).


Rodriguez knows her work is not finished. This winter, she is going to waters off the southern tip of South America. She hopes to make discoveries about the sea anemones there. "After I have an inventory of what species there are, I would like to study how they live," Rodriguez says.

check it out

Although most invertebrates do not take care of their eggs, or brood, some sea anemones do. A species that lives along the North American coast, Epiactis prolifera, attaches its eggs to its body with an envelope of mucus. To learn more about sea anemones, ask your teacher or check out several ecosystems of the world's oceans in the Milstein Hall of Ocean Life at the American Museum of Natural History (

Making Friends

Sea anemones sometimes form partnerships with other animals. Scientists call this behavior symbiosis. Here are some of sea anemones' best friends,


Clownfish sometimes live among sea anemones' tentacles. They are immune to the tentacles' toxins. Sea anemones give clownfish protection. In exchange, the fish clean the anemones' tentacles.


Hermit crabs act like a sea anemone taxi service. Anemones sometimes stick onto crab shells and ride to new places. In return, anemones give crabs protection from predators.


Sea snails give rides to some sea anemones in Antarctica. Rodriguez has described a new species of anemone that forms this relationship. "They go around together all the time," she says.


Set a Purpose

Learn how a scientist studies a strange sea creature.


* Estefania Rodriguez says that as long as a sea anemone is touched with the palm of one's hand, one usually will not feel pain. Although, if anemones touch areas with sensitive skin, like on the face, their stingers cause a burning feeling. Always avoid touching sea anemones. Only experts know how to handle them properly.

* Sea anemones come from an ancient line of animals that have existed for hundreds of millions of years. They are not well-represented in the fossil record, however. This is because they do not have hard parts that can fossilize easily.

* One of the keys to sea anemones' success is its ability to form symbiotic relationships with other animals. Not all of these partnerships are the same, however. When both animals benefit from a relationship, it's called mutualism. When one organism benefits while the other is harmed, it's called parasitism.

Discussion Question

* How does your relationship with your parents or guardians benefit you? (Possible answers: They love me; feed me; provide shelter; take care of my needs.)


Discussion Question

* Which of the sea anemones' pairings can be described as mutualism, a relationship in which both animals benefit? (Answers: All of them. Sea anemones benefit by being transported or by being cleaned. Clownfish, snails, and crabs benefit by being protected.)


* For photos and more information on sea anemones, visit: /animals/invertebrates/sea-onemone/
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Title Annotation:life science; sea anemones
Author:Goudarzi, Sara
Geographic Code:1USA
Date:Jan 1, 2011
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