AnemonesBy Kathy Kranking
Take an up-close look at these beauties.
UM, WHAT ARE THEY?
Sea anemones (uh-NEM-uh-nees) may look like strange plants, but they’re really animals—cousins of corals and jellyfish. There are more than 1,000 kinds of sea anemones. An anemone can be as small as a marble or as wide as a door is tall! And they come in lots of different colors, including red, green, pink, purple, and white.
TOP TO BOTTOM
The first things you notice when you look at a sea anemone are its tentacles. These fleshy, finger-like parts are what you see up-close all across this page. Below the tentacles is the main part of an anemone’s body. At the very bottom of that is a sticky, muscular foot. The anemone uses its foot to hold on to coral reefs, rocks, or other surfaces. Most anemones stay stuck where they are. But some can move by sl-o-o-w-ly sliding along. And some can let go and “swim” away by flexing their bodies or swinging their tentacles.
An anemone’s tentacles are more than just pretty. They’re the animal’s secret weapons. Here’s why: Each tentacle is packed with thousands of tiny stinging cells. Inside each cell are tiny capsules, each containing a coiled, thread-like “spear” filled with venom. When an animal touches the tentacles, the capsules fire the spears. Zap! The anemone uses these stingers to protect itself from enemies or to catch food. (Only a few anemones have stingers that are harmful to humans.)
Most small fish would be goners if they got too close to a sea anemone’s tentacles. But clownfish can hang out among the tentacles with no problem at all. That’s because clownfish are covered with thick mucus (MYOO-kuss) that protects them from an anemone’s stings. By staying close to the tentacles, the clownfish stay safe from predator fish. The clownfish may help the anemone by chasing away fish that are able to eat anemones. And when the anemone eats, the clownfish get to nibble on its leftovers. So everybody wins!
Even though anemones can catch lots of creatures with their tentacles, sometimes the tables are turned. Then the anemones become the prey. Certain kinds of fishes, crabs, and other creatures can munch on anemones without being bothered by the stings. But if an anemone is lucky, it can escape. The swimming anemone at right has let go of its foothold and is slowly floating away from a hungry sea star: anemone – 1, sea star – 0!
A sea anemone may not have a face, but it does have a mouth! Its mouth is hidden, surrounded by tentacles (left). An anemone paralyzes fish and other prey by using its tentacles to sting them. Then it uses its tentacles to move the food to its mouth and eat it. The anemone above has pulled its tentacles into its body as it slowly eats a sea star.
Some anemones live alone, while others, such as these purple-tipped anemones, don’t mind a crowd. They live close together in groups called colonies (KAH-luh-neez). Sometimes different colonies battle each other for space. Anemones on the borders of a colony will sting intruders from another colony to keep them from coming too close.
BABIES ON BOARD
How do anemones make more anemones? Different kinds have different ways. The eggs of the brooding sea anemone hatch inside the anemone mom’s body. Then the larvas, or young, swim out of her mouth and attach themselves to her. Can you see the tiny young anemones on this mom? They stay on her body, growing until they are big enough to survive on their own. Then the young anemones slide away to settle down and live by themselves.