by Kathy Kranking
After looking at their pictures, you may think sea anemones (uh-NEM-uh-neez) are plants growing on rocks or coral. But sea anemones might surprise you. For one thing, they're actually animals—cousins of corals and jellyfish.
And here's another surprise: Although anemones seem to be "planted" in one place, many kinds can move. At the bottom of a sea anemone's tube-shaped body is a sticky, muscular foot. The anemone uses the foot to hold on to rocks or other surfaces. Most anemones prefer to stay stuck where they are. But some move by sliding along slowly on their feet. Others just let go and float away or "swim" by flexing their bodies.
Despite their flowery looks, sea anemones are actually awesome predators. But they don't need teeth and claws to be tough. They have a secret weapon: Those pretty waving "petals" are stinging tentacles!
An anemone's tentacles contain thousands of tiny capsules. Inside each is a coiled, thread-like "spear" filled with venom.
When an animal touches the tentacles, the capsules fire the spears. Zap! The stingers can protect the anemone by warding off enemies. (Only a few anemones have stingers harmful to humans.) But the anemone also uses the stingers to get food. The venom paralyzes the prey, making it easier to eat. Then the tentacles move the prey to the anemone's mouth, in the center of the tentacles.
Sometimes the tables are turned, and anemones become prey rather than predators. A number of creatures like to munch on anemones. They aren't bothered by a sea anemone's stings. Sea slugs, for example, eat both the tentacles and bodies of anemones. Butterflyfish rip off the tentacles and gobble them up. Crabs use their claws to tear anemones apart to eat. And sea stars dissolve anemones with special juices oozed from their stomachs!
But anemones have some ways of trying to protect themselves when stinging doesn't work. They can slide slowly away or release their foothold and float or swim off. They can close up, pulling their tentacles into their bodies to protect them. Some anemones even have fish "bodyguards" that chase enemies away.
Here's yet another surprising thing about anemones: Scientists have discovered that some kinds have battles with each other! They fight to protect their territories. These anemones live in big groups close to each other. Between the groups is a "do not enter" zone. If anemones from either group start to move into that zone, things get ugly.
Along the edge of each group are "warriors." These anemones have special attack tentacles, which have stingers that are super-strong. The warriors use these attack tentacles to sting any anemone that comes too close. Zap! Zing! It's like an anemone war!
Now that you really know anemones, their awesomeness should come as no surprise at all!