Category Plants & Animals

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.

An Underwater Garden

When is a garden made of animals? When it is made by tiny animals called corals! Beautiful “gardens” cover the seafloor in warm, shallow parts of the ocean.

Thousands of corals live together in colonies. Coral colonies are made from limestone. The limestone forms a home where the corals live. Coral colonies can be shaped like fans, beach balls, candlesticks, and other shapes. They can be red, pink, orange, blue, green, or purple.

Each individual coral is called a polyp. Corals are actually relatives of jellyfish. Like jellyfish, coral polyps send out special feelers that sting tiny ocean creatures. The polyps eat these creatures.

Together, many corals form a coral reef. Coral reefs are the richest parts of the ocean. They provide a home for countless fish and other ocean animals. Many colourful creatures live and hide in the crevices and tunnels created by coral.

A Real Live sea Monster

It has eight long, rubbery legs and two huge, staring eyes. The octopus is so scary-looking to some people that it is sometimes called the devilfish. But octopuses rarely attack people. They use their strong arms, called tentacles, to catch shellfish and swim away from danger. Some kinds also have a poisonous bite.

There are about 50 kinds of octopuses. Most of them are about the size of a kitten. But some measure 8.5 metres from arm tip to arm tip.

The octopus is a mollusc. It has no bones, but a tough covering called a mantle protects its body and gives it shape. Rows of round muscles under each arm act as suction cups. These suckers can hold onto an object even if the octopus’s arm is cut off!

When an octopus is frightened it produces a cloud of inky liquid. The inky liquid makes it hard for an enemy to see or smell the octopus. That’s how the octopus gets away.

Magnificent Molluscs

Imagine having a soft body, with no backbone to hold you up and only one foot to help you move. That’s what clams are like. Clams belong to a group of animals called molluscs. Molluscs have soft bodies with no skeleton. Some molluscs, such as snails, clams, oysters, and scallops, have outer shells for protection. Slugs, octopuses, and squids are molluscs that have no outer shells.

Molluscs live in most parts of the world. Land snails and slugs live on land. Octopuses, squids, and oysters, live in the seas and oceans. Some clams and snails live in rivers, lakes, ponds, and streams.

Wherever molluscs live, they must keep their bodies moist to stay alive. That’s why slugs and some land snails can be found under damp leaves or in the soil.

Some molluscs live between two shells that can open and close like a book. These animals are called bivalves. Clams, cockles, mussels, oysters, and scallops are bivalves. Bivalves usually keep their shells open just a little so that food can drift in. They eat tiny plants that float by in the water.

Fish, mammals, and birds all have something in common – a backbone. They belong to a group of animals called vertebrates. But some of the most fantastic creatures in the sea are animals that have no backbones. They belong to a group of animals called invertebrates.

Some invertebrates are huge, like the giant squid. Others are so tiny that you need a microscope to see them.

Some invertebrates, like crabs, clams, and sea spiders, have hard shells. The shells protect their soft bodies. Other invertebrates, like starfish or sea urchins, have spikes to protect them. Jellyfish and other invertebrates are soft all over. Jellyfish look like see-through blobs. They float gracefully through the sea. Their stinging tentacles are their protection!

Whether they have shells, spines, or stinging tentacles, invertebrates are some of the most interesting creatures in the sea!

There are thousands of kinds of fish. If you tried to choose the most fantastic fish, you’d have a hard time.

The mudskipper has a head like a frog and a body like a fish. It often crawls onto land. It can jump up and catch flying insects in its mouth.

The archerfish shoots its food down with water. The archerfish swims at the top of the water until a beetle comes buzzing past. Then the fish shoots a stream of water from its mouth. The water hits the beetle with such force that it falls down into the water. The archerfish gobbles it up.

The elephant-nose mormyrid is well named. Its long nose looks Re an elephant’s trunk.

Leafy sea dragons are odd-looking, too. Their spiky fins make them look like pieces of seaweed.

A gulper eel looks just like a huge mouth with a long, tapering tail attached to it. It can open its mouth wide enough to swallow a fish much larger than itself.

A flounder has both eyes on one side of its body. And let’s not forget the glass catfish. You can see its insides.

These are just a few of the strange fish that live in the world. Which do you think is the most fantastic?