Category Plants & Animals

Crawling on Six Legs

They buzz. They prowl. They crawl. Some munch leaves, others sip nectar. Some crunch wood. A few drink blood. They can be as small as the eye of a needle, or as big as a grown-up’s shoe. What are they? Insects!

Insects live just about everywhere, from the steamiest jungles to the coldest mountaintops and the driest deserts. No matter where you live, you’re sure to see insects buzz, prowl, or crawl by.

Flies, ants, bees, grasshoppers, beetles, crickets, and butterflies are all in the group of animals called insects. Like all insects, these creatures have six legs. Most insects also have wings.

Insects do some amazing things. Some insects, like flies, taste with their feet. Most insects smell with two wiggly feelers on their head called antennae. Some insects have no eyes, while others have five or more. Many insects hear with hairs on their bodies, while others have “ears” on their legs or on the sides of their bodies.

Meet the Arthropods

What’s an eight-legged creature that catches other animals in a trap? A spider! What six-legged jumping animal has ears on its sides? A grasshopper! What’s a ten-legged tunnel builder? A crayfish!

The world is full of these many-legged creatures called arthropods. An arthropod’s body is divided into several sections. Each section is covered with an outer shell. Arthropods have no skeleton inside their bodies, but their hard shell protects them. Large arthropods, such as crabs and lobsters, have a thick, heavy shell. Small, flying arthropods like bees and butterflies have a much lighter covering.

Arthropods live everywhere—jungles, deserts, oceans, caves, mountaintops, and in your own garden. You can watch them creep, crawl, and fly all summer long. If it has many legs and its body is divided into several sections, it’s an arthropod.

Dainty but Deadly

Some of the daintiest creatures in the sea are the deadliest to small fish and shrimp. Both the sea anemone and the jellyfish look like pretty flowers, but they sting their prey with poison.

The sea anemone got its name because it looks like the flower called an anemone. The animal lives on the bottom of the sea, often in a warm coral reef or a rock pool. A sea anemone can move slowly, but it prefers to stay in one spot.

To catch small fish and shrimp to eat, the sea anemone spreads out its arms. Those arms are filled with tiny stinging parts. When the anemone touches its prey, it shoots out a poison. The poison stops the creature from moving. Then the sea anemone uses its arms to carry the creature to its mouth.

The jellyfish looks like an upside-down tulip. Its body is like a see-through umbrella with long strings hanging down. The jellyfish is made mostly of water. Washed up on the beach, it looks like a lump of colorless jelly.

The jellyfish swims by opening and closing its whole body. When it stops moving, it sinks to the bottom. As it drifts down, it catches small animals by stinging them with its tentacles.

Starry Creatures

What kind of animal has eyes and feet on its arms and pushes its stomach out of its body when it eats? A starfish!

Starfish have tough-skinned bodies shaped like a star. They usually have five arms, sometimes more. Underneath each arm there are little tubes. These are the feet of the starfish. And the small reddish spots at the end of each arm are its eyes!

When it finds a clam, the starfish climbs on top of it. Its tube feet stick to the clamshell like glue. Then the starfish slowly begins to pull the shell apart. Soon the shell is a little way open-just a tiny crack. The starfish then pushes its stomach through an opening in its body and between the two halves of the shell. Juices from the starfish’s stomach turn the clam to mush. The starfish digests, or breaks down, the clam inside the clam’s own shell.

If a starfish loses an arm, it grows a new one! In fact, if the starfish is torn in two, each half grows into a new starfish.

Fuzzy Biscuits and More

The ocean is full of amazing animals. A sand dollar looks like a fuzzy biscuit, but it’s an animal that lives in the sand. It moves about on many feet that look like tiny tubes. People often find the white coin-shaped skeletons of sand dollars on the beach.

A sea cucumber isn’t found in a garden. It’s an animal with a long round body that looks a little like a garden cucumber. At one end are its “fingers” and mouth. The animal uses its fingers to catch food floating in the water. Then it puts each finger, one at a time, into its mouth and enjoys a tasty meal.

Another unusual animal looks like a creeping pincushion. This creature, called a sea urchin, is related to the starfish, but it is round and plump.

Sea peaches belong to the family of animals called sea squirts. Most kinds of sea squirts are just round bodies with two openings like little mouths. One mouth sucks water in. The other squirts water out. The sea squirt eats the tiny animals and bits of plants in the water it sucks in.

Life under a Microscope

If you picked up a cupful of seawater, you might see a few creatures. But, if you looked at the same cup of water under a microscope, you would see hundreds or thousands of little creatures!

Some of the creatures are tiny animals. Some are the young of bigger animals. You’d also see living things like plants. Huge masses of these animals and plants drift in the ocean. Together they are called plankton. Plankton is food for a great many sea creatures, from shrimp to whales.

In a cupful of pond water you would see different creatures. One looks like the bottom of a shoe. It’s called a paramecium and has no head and no legs. It doesn’t have eyes or a mouth either. Its body is covered with rows of little hairs called cilia that it uses like oars to move through the water.

Another creature looks like a funnel with a long tube. It creates a little whirlpool around the top of the funnel to draw food into its body. This creature is called a vorticella.

Another creature found in ponds is an amoeba. It looks like a blob of grey jelly, and it changes shape every time it moves.

Even though these creatures are microscopic, they are an important part of the world of animals. Without them, many other animals would go hungry.