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Satellite Savvy Global Gang Learn About the Ocean

Learn About the Ocean

From the list of topics below, scroll down the page to find out about some of the strange and wonderful creatures that live in our oceans.

A Fish that Walks and Talks?
The Simply Super Sponge
Why Are Fish in Schools?
How Fish Breathe and Fin Facts
What Animal Is Named for a Vegetable?
When is a Crab Not a Crab?
What Animal Is the "Pilgrim of the Sea?"
What Animals Live in Spiral Homes?
Are Barnacles Alive?
What Ocean Animal Could Be Called "Big Foot"?
Are There Stars in the Sea?
Do You See a "Walking Pincushion"?
What Story Does the Sand Dollar Tell?
Who is the Master of the Low Profile?
The Loveable Lumpfish
What Fish Can Change its Size?
What's Peculiar About the Pipefish?
Lobster Lore
Why Do Crabs Shed Their Skins?
Do You See a Hinged Animal?

A Fish that Walks and Talks?

The fierce-looking sea robin is one of the more bizarre "Mysteries of the Deep." Their large heads are armed with sharp spines over each eye and around the skull. They grow up to 11 inches long and are very swift swimmers.

Sea robins have six spiny "legs," three on each side. These legs are really flexible spines that were once part of the pectoral fin. Over time, the spines separated themselves from the rest of the fin, evolving into feeler-like "forelegs." It was once thought that the fish used these legs to walk along the ocean floor, but the sea robin actually uses them to stir up food.

Vibrating its fins to stay in place, the sea robin "hovers" a few inches above the ocean bottom and pokes the sand or mud with its spiny "legs." This probing uncovers worms and mollusks, and also frees bits of edible matter that float up to the robin's mouth.

Sea robins are quite vocal, making grunting noises much like the oinks of a young pig. A large group can be surprisingly loud - and startling to divers and fishermen.

The Simply Super Sponge

Sponges are very simple animals that live underwater in both oceans and lakes.

Some scientists believe that sponges are not just one animal, but a colony of animals living together. Each sponge cell is really a separate animal. Singley, they would be too small to survive, but together they form a stronger structure, with each cell performing its own special duty: some filtering for food, others removing waste and so on. In fact, break a sponge into a hundred pieces and you'll have a hundred separate animals.

Sponges have a network of pores and hollow tubes throughout their bodies, which allows water to flow through. They eat tiny animals and plants, which they filter from the water. But not all animals are eaten. Some small shrimps and crabs make homes inside sponges, feeding on the procession of tiny food sources floating through. One sponge had 900 small crabs living inside!

Sponges can be as small as a pebble or six feet tall; they can be red, purple, yellow, blue, brown or even pink. The same type of sponge can look completely different depending on where it is found: a sponge growing in shallow water and pounded by waves may be flat, while one living in deeper, calmer water may have a tall, branching shape.

Why Are Fish in Schools?

A "school" of fish is just a big group that swims together. There are many reasons why fish school, but most have to do with avoiding predators. There is safety in numbers. Big groups lessen the odds of any one fish being eaten - with the safest fish being those in the middle. So many fish swimming around at once also confuses predators.

How Fish Breathe

Even though fish live underwater, they still need to breathe. Nearly all fish rely on gills to take in oxygen dissolved in the water. Water is taken in through the fish's mouth and passed over the gills, which absorb the oxygen. Some species of fish can also breathe through their skin, and a mysterious few have lungs which permit them to breathe much like we do.

Fin Facts

All fish have fins, although they may look very different on different types of fish. Fins give fish both movement and stability. They help ward off predators and stir up food. Sometimes their shape helps a fish blend in with its environment and hide from possible attackers. Try to find each type of fin on all the fish you see. What might each kind be used for? Think about how various kinds of fish eat and swim.

What Animal Might Be Named for a Vegetable?

If you touch the sea cucumber, its elastic and leathery body looks like a vegetable, yet it's really a mass of muscles wriggling through the sea. This simple animal can eat 100 pounds of tiny sea plants and animals each year! The cucumber sweeps up little organisms with the sticky, finger-like feelers around its mouth then licks its feelers like a baby eating. When attacked, they squirt out part of their insides. This doesn't hurt the animal, and gives its attacker something to eat while the cucumber gets away.

When is a Crab Not a Crab?

When it's a horseshoe crab! The horseshoe crab is more closely related to spiders and scorpions than to real crabs. It's named for the horseshoe-shaped front edge of its carapace or top shell.

Horseshoe crabs are most active at night, and are often found rummaging through bottom sand for the worms and mollusks they eat. They can swim, although awkwardly, and are sometimes seen wiggling through the water upside down.

Like most crabs, horseshoes molt, shedding their shells as they grow. The horseshoe "remains" found washed up on beaches are nothing more than these cast-off shells.

This simple animal is almost considered a "living fossil." Horseshoe crabs are one of the most ancient animal species still living today, and were already well established in the Earth's oceans millions of years before the Age of the Dinosaurs.

What Animal Is the "Pilgrim of the Sea?

Meet the scallop, one of the ocean's wanderers. Scallops are marine animals called bivalves, meaning they have two valves, or shells, joined by a hinge of ligament and muscle. Clams, mussels and oysters are also bivalves.

Unlike other bivalves, scallops don't fasten themselves to rocks or pilings, or form beds as oysters do, but instead travel from place to place. They move by clapping their two shells forcefully enough to push forward in funny, zigzag leaps. The extensive journeying of the scallop makes it a fitting emblem for travelers. In the Middle Ages, pilgrims sometimes wore a scallop symbol on their hats to show they had taken long sea voyages.

The deep-sea scallop is the most common scallop in this area. It's found at snorkeling depths in Maine, but is usually commercially harvested from deeper water. Its flat, fine-ribbed shell may span eight inches. The blue dots around the shell's inner edge are rows of tiny eyes.

What Animals Live in Spiral Homes?

These animals are "univalves," meaning one-shelled. Their shells are usually spiraled, but the animal inside is not coiled. A univalve's head looks like a snail's, with two pairs of tentacles. The short pair at the front is for touch, smell and taste, while the longer pair in back holds the eyes. Univalves move by means of a thick, muscular foot protruding from the bottom of their shell. They crawl slowly about the tide pool, feeding on algae and small animals, including other univalves. Pick up a periwinkle; hum to it, and the animal peeks out of its shell.

Are Barnacles Alive?

Barnacles are small animals, which "glue" themselves to rocks, piers, ships, and even turtles and whales. Inside its hard shell, the barnacle has a soft, shrimp-like body. At feeding time, the animal opens its shell at the top, sticks out three pairs of feathery legs, and waves them back and forth to capture small food particles.

What Ocean Animal Could Be Called "Big Foot"?

The northern moon snail's large foot is a handy tool for catching clams and mollusks. When dinner is found, the moon snail pins the animal with its big foot, then drills through the shell with its toothed tongue to the food inside. Moon snails get their name from their large, round, bluish-white shells. The snail seems too big for its shell, but can hide completely inside if threatened.

Are There Stars in the Sea?

The North Atlantic is alive with many species of sea stars, or starfish. They come in different colors, shapes, and sizes. Some live along the muddy ocean bottom, while others prefer rocky tide pools. All sea stars are predators, and eat other animals, but some have specialized tastes and feed only on certain animals, such as sponges, sea cucumbers, clams or even other sea stars. Bottom-feeding fish prey on sea stars.

Mud Star The mud star is brownish-yellow in color and can grow up to four inches across. It gets its name from living along muddy ocean bottoms, usually in water up to 20 feet deep. Mud stars are found from Cape Cod north to the Arctic.

Blood Star Blood stars can be purple, yellow, red, orange or even flesh colored. They feed almost exclusively on sponges, and are common to tide pools and rocky shallows. The skin of a blood star is grainy to the touch, with more equal-sized spines. Blood stars generally grow about two inches across.

Common Sea Star Our most abundant sea star is also the most colorful, appearing in shades from olive, brown, yellow, and orange to red and purple. The young are almost white. The tube feet of these sea stars are in four rows, while all other species have two rows. They can grow up to 16 inches across, and are found from Labrador to Cape Cod in tide pools and under jetties, pilings, sand and stones.

Daisy Brittle Star This sea star's name is appropriate since the animal can literally fall apart if handled roughly. They are found from tide pools to water 5,000 feet deep and are our most common brittle star. Their colors vary.

Clams, mussels and oysters are the sea star's favorite foods, but won't fit in the animal's mouth. So, it has developed an unusual way to eat. Using powerful suction-cup arms, the sea star pulls open a clam, then pushes its stomach out of its mouth into the clam's shell and digests the soft body.

Do You See a "Walking Pincushion"?

If so, you've found a sea urchin; the urchin's hard, spiny shell protects its soft body. The animal's mouth is on the underside of its body, so it eats as it crawls along, scraping algae off rocks with sharp little teeth. Sea urchins are also masters of disguise, using their tiny tube feet to cover themselves with seaweed and small rocks for camouflage.

What Story Does the Sand Dollar Tell?

Legend has it that the sand dollar shows the Birth and Resurrection of Christ. An Easter lily, the Star of Bethlehem, a Christmas poinsettia and a bell are all outlined on the animal's shell. The Easter lily and poinsettia markings are really rows of tube feet, allowing the animal to move and burrow in the sand. Sand dollars eat tiny plants and animals. They range in color from dark brown to red and are covered with a felt-like coating of fine spines.

Who is the Master of the Low Profile?

Gliding about the ocean is the winter skate, one of about half a dozen skate species found in the Gulf of Maine. You may also see winter skates in aquarium tanks. If so, look for the eye-like markings on front and back. You should also spot a row of spines along its tail and dorsal side. Winter skates are brownish in color and can reach lengths of 43 inches.

Skates live in a flat area, near the river or ocean bottom, and their coloration blends with their surroundings. Skates spend much of their time partially buried in the sand or mud waiting for a meal to pass by. They feed on a wide variety of crustaceans, such as clams and snails, and smaller fish. Nostrils on either side of their mouth allow them to scent their prey, which they then crush with batteries of tough, rounded teeth.

A walk along the beach will often turn up a skate egg case, a dark, oblong, leathery sac which helped protect the eggs and young skates before they were born. The cases are sometimes called "mermaid's purses."

Skates have commercial value, being the most common "fish" used to make Fish 'n Chips; they are also frequently cut up and sold as scallops.

The Loveable Lumpfish

Round, stocky, and covered with odd bumps the lumpfish has a rather mismatched appearance.

Adding to their unusual features, lumpfish have a sucker disk on their bellies which they use to attach themselves to clumps of mud, stones, lobster pots, boats, pilings and floats. Once securely fastened, the lumpfish stays put, eating small crustaceans, worms and other tidbits brought to it by the tide.

Female lumpfish are about a foot long when full grown, while males reach only about one-third that length. Although generally found offshore, lumpfish come into shallow waters to spawn. There the female lays her eggs, then returns to deeper water. The male stays behind to guard the eggs, fanning them with his fins until they hatch. The eggs, or roe, are sometimes eaten by humans as a "poor man's caviar."

Since the eggs are hatched in shallow water, it is not unusual to see young ones just offshore and occasionally even in tide pools.

What Fish Can Change its Size?

Meet the sea raven, a most distinctive-looking fish. With its jagged dorsal fin and numerous fleshy tabs sticking from its head, the raven is sometimes mistaken for a piece of seaweed-until it's aroused.

When caught or irritated, the sea raven has the curious habit of inflating its belly with water so it can look larger. However, if the fish is removed from the water while in this expanded state, it can't deflate and will remain floating on the surface. Sea ravens also hum and vibrate if handled, although no one is sure if this is a sign of annoyance or fear.

A member of the sculpin family, the sea raven is common from Labrador to Chesapeake Bay and is usually found in water up to 600 feet deep. It comes in a wide range of colors, from dark brown to brick red and even bright yellow, and grows up to a foot in length and seven pounds in weight.

What's Peculiar About the Pipefish?

The pipefish (left) is a cousin of the sea horse (right); one look at their heads shows the similarity. Despite the sea horse's fanciful name, both belong to the fish family. Neither fish can swim very fast, so both have heavy "armor plating" scales for protection.

Sea horses are found only in the southern section of the Atlantic Ocean, from Cape Cod to Florida. Pipefish are found throughout the Atlantic.

In most of the animal kingdom, the female carries the young, but with pipefish and sea horses, the male has a special brood pouch on his abdomen allowing him to carry the eggs and young until they are ready to be born.

Pipefish are usually found among the eelgrass in the estuary. Combined with their slim, "pipe cleaner" body, their dark brown color allows them to blend in easily with their environment.

Lobster Lore

Lobsters normally have two claws, one for tearing their food and one for holding or crushing.

Losing a claw is not unusual. Lobsters may lose them in fights with other lobsters, or when fleeing some danger. The missing claw can eventually grow back.

Lobsters eat a wide variety of fish and invertebrates, including other lobsters. Lobsters may reach a length of more than three feet and weigh more than 45 pounds.

These animals are generally greenish-black in color, but blue and albino specimens have been found.

Why Do Crabs Shed Their Skins?

Crabs belong to the Crustacea family. Crustaceans have skeletons on the outside of their bodies in the form of shells. They shed their shells when their bodies outgrow them. When the shell cracks, the crab crawls out. A new shell has grown under the old one; it is soft at first but later hardens. Crustaceans may get new shells every year, or several times a year, depending on how fast they grow. (Be careful of crabs--they can pinch!)

Do You See a Hinged Animal?

The animals pictured here are bivalves, meaning they have two valves or shells, joined by a hinge of ligament and muscle. Most bivalves live in one place, fastening themselves to rocks and pilings, or forming beds, as oysters do. But scallops travel by clapping their two shells together forcefully enough to push forward in zigzag leaps. You can tell the age of some bivalves by counting the rings on their shells; each ring represents another year's growth.

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