Annelida
AnnelidaArthropodaBaleen
WhalesBetween
the TidesCalifornia
Gray WhalesCnidariaDecapodsEchinodermataFishesMapping
MigrationMarine
AlgaeMolluscaOur Fin-Footed
FriendsPinnipedsPoriferaSharksSharks
& Rays in the ChannelA Snail's
PaceA Whale
is NOT a Fish!
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Sponges are the most primitive multicelled animals. They have no organs, such as a mouth or stomach, and no tissue such as skin. Unlike most multicelled animals, the cells of sponges are loosely grouped together. In some special instances, individual cells can function alone for a period of time if separated from the others. Most sponges grow in the sea, but a few species live in fresh water. Sponges belong to the phylum porifera (pohr IH fehr uh), which means "pore-bearing." This name describes the tiny holes scattered over the bodies of sponges. Sea water flows in these openings through a system of branched canals. The cells of sponges have tiny whiplike structures called flagella (fluh JELL uh) which line the canals and create this flow of seawater. The water is then filtered for food and oxygen and channeled out of the sponge's body through different openings. Sponges are stiffened by a unique "skeleton" consisting of tiny needlelike, intertwined supporting rods called spicules (SPIK yoolz). In contrast to other sea creatures, sponges have a distinctive gritty feel to them. A few sponges, such as the bath sponge, are soft and have horny threads instead of sharp spicules. Although most sponges measure just a few inches in width, sponges can grow to be several feet wide. Both shape and color may vary -- red, purple, yellow, and white forms are found locally. Sponges grow under rocks and ledges in the low tide zone. |
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What do sea anemones, corals, hydroids, and jellyfishes have in common? They are among the varied animals that make up the phylum cnidaria (nye DEHR ee uh). The basic cnidaria body plan is radial, with a central mouth surrounded by a circle of tentacles. Some, like sea anemones, have a cylindrical polyp (PAHL ihp) body type that is firmly attached to a rock, with the mouth and tentacles facing upward. Others, like the jellyfish, are free-swimming creatures of the open seas. They have the umbrella-shaped medusa (muh DOO suh) body type with long tentacles that hang down. The mouths of these unusual creatures are used both for ingesting food and eliminating wastes. The carnivorous cnidarians are "sit and wait" predators which feed on animals that wander too close. These unusual animals are equipped with stinging cells, called nematocysts (NEHM uh toh sistz), usually located on the tentacles. They use these stinging cells to paralyze and capture prey and to defend against their enemies. The cells contain a tightly coiled thread ready to be discharged when touched. They are also chemically stimulated by the presence of food. Humans swimming in the ocean are often stung by jellyfishes. Unless you are allergic to the poison, the sting is usually nothing to worry about. Wash the affected area with an ammonia solution to reduce the pain. |
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What small animals are found in every habitat in the marine environment? Segmented marine worms, members of the phylum annelida (an uh LID uh), fill the bill. The habitat for these various species ranges from the depths of the ocean to the high tide zone. The word annelida, meaning "ringed," describes the ringlike body segments of these creatures. Generally, each of the segments has its own organs and is identical to the segments before and after it. Each segment also has two paddlelike structures called parapodia, which protrude from the body. Each parapodia is supported by a bundle of stiff bristles. The parapodia and bristles are used for movement and defense. Tube worms, blood worms, lugworms, clam worms, and fanworms are some of the varied species of annelids. Ranging in size from 1/10 inch to 6 feet, their feeding methods are equally diverse -- some are scavengers, some are vegetarians, some are predators, others are filter-feeders. One such filter-feeder, the fanworm, is topped with a distinctive funnel-shaped crown of tentacles. These tentacles are used for feeding and the exchange of gases. Hairlike cilia (SILL ee uh) on these tentacles sway to create a water current. Food particles in the water become trapped on the cilia, and are carried down to the fanworm's mouth in the center of the funnel. |
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Whenever you visit the beach, you will find remnants of mollusks that have washed up on the sand. The word mollusca (moll UHS kuh) comes from the Latin mollis, meaning "soft." This describes the soft, unsegmented bodies of animals such as nudibranchs, octopuses, squids, snails, shellfishes, and chitons that belong to this phylum of invertebrates. Most mollusks have a fleshy mantle that secretes lime, thereby creating a hard shell which protect their soft bodies. Sometimes visible and sometimes hidden in the soft parts of the animal, these hard shells are extremely durable. That's why you find so many shells on the beach long after the animals that inhabited them have died. Most mollusks move about on a broad, muscular foot. Another characteristic of this phylum is the radula (RAD yoo luh), an organ that looks like a flexible strip of sandpaper. Like a rasping tongue, the radula is used to scrape plants off rocks or to bore through the shells of other mollusks to get to the delectable, soft body inside. With more than 40,000 species, snails are one of the more numerous animals on earth, and the majority of them live in the sea. Most snails begin their lives in a spiral form, but in some groups, such as limpets, the spiral is not noticeable in adults. The opening in the shell of most snails is protected by a trapdoor called an operculum (oh PUHR kyoo luhm). Depending on the shape and number of teeth in the radula, some snails eat plants, some eat other animals, and some eat both! Predatory and scavenger snails usually have a long, retractible proboscis (proh BAH sihs) with the radula and mouth at the tip. This allows the snail to get at hard-to-reach prey such as tube worms. They may also have a siphon (SYE fun), a tubular extension of the mantle that draws water into the mantle cavity. These predator and scavenger snails can detect the scent of their prey by moving the siphon in different directions. Moon snails use the radula to drill holes in the shells of other mollusks. |
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Have you ever watched a snail move? Snails are univalves, singl-shelled mollusks that move about on a flat, muscular foot. Next time you visit the beach at low tide, try this experiment with a marine snail, a land snail, or a freshwater snail. Afer the experirnent, be sure to return the snails to the exact place you found them! You will need:
Follow these steps:
To find out the snail's speed, use these formulas:
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Repeat Steps 1-5 with the other snails. Compute the speed and record the results in a table like the one shown below:
| Snail Name or number |
Length in inches |
Distance in inches |
Time in seconds |
Speed per second |
Speed per minute |
Speed per hour |
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At least eighty percent of all known animals are arthropods. The word arthropoda (ahr THRAH puhd uh), meaning "joint-foot," refers to the matched pairs of jointed legs that these creatures have. Although most arthropods, such as insects and spiders, make their home on the land, others, such as barnacles, copepods, shrimps, lobsters, crabs, and sea spiders, are important inhabitants of the marine environment. The body of an arthropod is covered with a cuticle of rigid material called chitin (KYE tin). In most cases, this is formed into rings around the animal's body to allow for easier movement. This armorlike exoskeleton provides protection for the animal's body. In order to grow, the arthropod must periodically shed this exoskeleton and replace it with a new covering. Because of their thick shell, barnacles were once classified with mollusks. After close observation, it was discovered that barnacles are related to crustaceans (krus TAY shunz) such as shrimps and crabs. In the early stages of their life cycle, barnacles swim and drift until they find a suitable place to settle down. They then attach their heads to a suitable surface -- a rock, a piling, a ship's hull, even a whale's skin -- and secrete several thick, hard plates for protection. At this point they are considered adults and are no longer able to move around. Acorn barnacles have an interesting way to get food. Their bristly legs, called cirri (SIHR eye), sway rhythmically through the water. The waving cirri filter small food particles through their coarse bristles and then scrape the food from the bristles into the barnacle's mouth. Gooseneck barnacles are not filter-feeders. They use the cirri like a hand to grasp or catch larger food particles. |
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What sea creatures use water to operate their tiny tube feet? Sea urchins, sea stars, brittle stars, sea cucumbers, and sand dollars are echinoderms (ee KYE noh duhrmz), which means "spiny-skinned." Species in this phylum have a water vascular (VAS kyuh luhr) system. This complex arrangement of tubes carries water throughout their bodies, and the water pressure generated by muscular contractions operates their tubelike feet. The feet are used for movement, food gathering, and as sense organs. The body plan of echinoderms is called radial symmetry (RAY dee uhl SIM uh tree), which describes the symmetrical body sections radiating from a common central point. All echinoderms have an interior skeleton of small, fused, overlapping, intertwined, or separated hard crystals of calcite (KAL syte). These crystals, called ossicles (OSS ih kuhlz), come in a variety of strange shapes and are embedded in the flesh of the creature. Small structures, called pedicellariae (PEHD ih sell ahr ee ay), are located on the external skin of echinoderms. Often built like pliers, they have a protective function. They keep barnacles and other creatures from attaching or preying on them. Sea stars, such as bat stars and blood stars, have a mouth with no teeth located in the center of the underside of their bodies. When feeding on prey like mussels, the ochre star uses the suction tips on its tubelike feet to pull the prey to its mouth. At this point, the sea star's stomach protrudes from the mouth, extends into the shell, and digests the tasty snack. Some species of echinoderms, including sea stars, are able to regenerate, or grow, new body parts when one is lost. This process starts almost immediately. Did you know that a sea star's lost arm will also begin to grow a new sea star? |
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What do you have in common with fishes? Fishes are vertebrates (animals with a backbone) just like you. Fishes have two sets of paired limbs which take the form of pectoral (PEHK tohr uhl) and pelvic (PELL vik) fins, but these limbs are not at all like your arms and legs. Along with the unpaired dorsal (DOHR suhl), anal (AY nuhl), and caudal (CAW duhl) fins, these fins are used for steering, stabilizing, and braking in the water. 
Bony fishes have something called a swim bladder that holds or releases gases into the fish's blood. This changeable balloon inside the body of the fish helps it maintain its swimming position at a certain level in the ocean. The lateral line along the side of the fish's body is a kind of sixth sensor sensitive to vibrations in the water. A flexible armor of tiny plates, called scales, covers the bodies of most fishes. As a fish grows older, the scales grow larger. You can tell the age of a fish by studying the growth rings on individual scales. We get oxygen from the air around us, but fishes get oxygen from the water. They have special organs, called gills, that perform the same function as our lungs. The gills appear red because of their rich supply of oxygen-filled blood. Fishes draw water into their mouths. The water then passes through the branched gills and out again through the gill covers located on either side of their bodies. |
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Which animal is one of the fastest swimmers in the ocean? With their sleek, streamlined shape, sharks are known to reach speeds of more than 40 miles an hour! The back and forth motion of their strong, powerful tails, propels sharks through the sea. Sharks are vertebrates, but their skeletons are made of cartilage (CAHRT uhl ij) instead of bone. Cartilage is the same translucent, elastic tissue that our noses and ears are made of. Their skin is covered with tiny, toothlike scales, called dermal denticles, making it rough and sharp to the touch. Like bony fishes, sharks live in the water and breathe through gill openings. Although they don't have noses for breathing, sharks do have nostrils, which give them a keen sense of smell. This helps guide them to their prey. Experts have differing opinions about the eyesight of sharks, but they all seem to agree that sharks don't depend on vision to survive. Sound and smell provide them with much of the sensory information they need. Sharks don't have the swim bladder found in bony fishes. They are able to remain relatively buoyant because of their enormous oily liver. Oil is lighter than water, so the liver helps sharks to remain afloat. Even so, most sharks must swim constantly to prevent sinking. This movement provides oxygen to sharks by keeping a flow of water passing over their gills. Twenty-five species of sharks live in the Santa Barbara Channel. Some spend their entire lives here, while others are only visitors. Various species of sharks are born in different ways. Some hatch from leathery eggs with hooks that catch onto sea plants. Others, like the basking shark, are born alive. The third method is a combination of the other two: the young hatch from eggs in the body of the female. Most sharks prey on large sea animals. However, the two largest species, the basking shark and the whale shark, feed on tiny crustaceans and organisms that they strain from the ocean. With their strong teeth, sandpaper-like skin, and great speed, sharks are deadly predators. Other animals in the ocean may be smarter, but no other creature has such fierce weapons! |
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A shark may go through as many as 1,000 teeth during its lifetime! Sometimes, when a shark tears out a chunk of meat, one of its teeth falls out. Shark teeth have shallow roots, and are arranged in rows around its huge, powerful jaw. A shark may have from five to fifteen rows of knife-sharp teeth. When one is lost, another moves forward in the jaw to replace it. Different species of sharks have different types of teeth that are adapted to the food they eat. By studying a shark's tooth, experts can tell what species it came from. Not all sharks have sharp teeth for tearing. Some have flat peg-like teeth for crushing the shells of crabs and crustaceans. Shark teeth are a common type of fossil found by scientists. Some of these fossils take the form of a mold, or impression. Have some fun creating your own "fossil" mold of a shark tooth: You will need:
Follow these steps:
Study your shark tooth impression closely, then answer these questions:
*Shark teeth and jaws can be purchaeed through biological supply houses or from hobby and shell shops. |
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Read the description of each of these Santa Barbara Channel residents. Use the facts to help you find its picture at the left. Can you match the description to the correct picture? The 45-foot-long basking shark is the second largest fish in the world. This giant is often seen at the water's surface. It cruises the channel with its huge gaping mouth open, feeding on zooplankton and small fish. The great white shark is not white at all, but a grayish-brown with a distinctive black spot on its side under the pectoral fins. It likes to roam near the shore looking for prey. The round stingray is a close relative of sharks. Pectoral fins attached to its head propell it through the water. Swimmers are often stung by the venomous barb at the end of its tail. The swell shark is found in rocky areas of the channel. Its name describes the way this shark protects itself from predators: it takes in large gulps of water which expands its body so it gets tightly wedged in a crevice and can't be pulled out. Its egg case is often called a "mermaid's purse." |
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Between the high and low tide lines is a zone of transition separating the land and sea. Twice each day, this intertidal zone is alternatively covered with water or exposed to air. It is the home for plants and animals that can survive living both in the sea and in the air. Plants and animals living in the intertidal zone must be able to withstand strong sunlight, crashing surf, and changing tides. Because of the constant pounding of the surf, animals must hang on or hide in order to survive. Plants must either hold fast or be washed ashore. The sun has an especially strong influence on life in the intertidal zone. It can desiccate, or dry out, organisms that are exposed during low tide. Heat from the sun increases the water temperature in standing pools, while evaporation increases their salinity. Fresh water from heavy rains or runoff can also affect the salinity of tidepools. Most organisms have adapted well to these ever-changing conditions. Although well-protected against the forces of nature, the plants and animals of the intertidal zone are not entirely protected from man. Man's impact on the intertidal zone can easily disturb the balance within a tidepool community. Hazardous chemicals from waste disposal can harm species that feed on the ocean's bottom. Manmade or natural oil seepage can clog tidepool animals so they are unable to live or avoid being eaten. Careless tidepool explorers can crush animals and leave others exposed. Fortunately, California's tidepools are protected by law. People caught removing or harming tidepool life may be fined as much as $500. |
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Marine plants provide about 70% of the world's oxygen. Ranging in size from microscopic phytoplankton to the giant bladder kelp, these plants are an essential resource. Species such as Irish moss, sea lettuce, and laver are eaten throughout the world. Several kinds of kelp are harvested. To do this, the top few feet of the plants are cut off periodically, processed, and used as a binding agent in many paints, cosmetics, medicines and foods. Kelp meal is also used as a diet supplement and as a filler in animal feed. The hundreds of species of marine algae (AL jee) have adapted to living in a harsh environment. They get their nutrients directly from the sea water. If a freshwater plant were placed in seawater, all the water in its cells would soon diffuse out of the plant, and it would shrivel up and die. Algae have specialized cell walls that allow them to tolerate high concentrations of salt. The three major divisions of algae are classified according to their pigments. All algae contain chlorophyll (KLAWR uh fil), a pigment they use for photosynthesis (foht oh SIN thuh sis). In this complicated process, the algae plant uses carbon dioxide, water, and energy from the sun to create its own food. Algae also have accessory pigments that blend with the chlorophyll to color the plants. Red alga grows at the lowest levels of the ocean because it can still photosynthesize in weak light. No alga grows deeper than 100 meters because absolutely no light reaches that level. Red and brown algae have accessory pigments that match their names, while green algae has one that is yellowish-orange. However, the sun's bleaching and drying, as well as repeated rubbing from the sand, often make it hard to tell which alga belongs to which division. |
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The bodies of pinnipeds are well-adapted for life in the ocean. The name pinniped (PIN uh ped) means "fin-footed." These marine mammals use their fin-footed flippers to row through the water. They are excellent swimmers and move much faster in the water than on land. Under their thick, furry hide is a heavy layer of fat, or blubber, to protect them from the cold. The blubber is bouyant, helping them float in the water. Pinnipeds are excellent divers, often staying underwater for thirty minutes at a time! During these deep dives, they are able to close their nostrils to keep water out. Their eyes are protected from the intense water pressure by a thick, hard lens covering. The three families of pinnipeds are true seals, eared seals, and walruses. Walruses are found only in Arctic waters. Great numbers of seals and sea lions make their home in the waters around the Channel Islands. The rich environment of the kelp forests provides plenty of food, and few people are around to disturb the animals when they come ashore to rest or tend their young. When a seal or sea lion crawls up onto the beach to haul out, people often want to help the animal back into the water. It's best to leave the animal alone; pinnipeds like to dry off in the sun and rest just like people do. Some species spend much of their time lying on the beach, returning to the water to catch food. Both seals and sea lions are carnivorous, eating fish, squid, crabs, and other small sea creatures. Fur seals and sea lions, or eared seals, have small external ear flaps and large pectoral flippers. These pectoral flippers are used in an up and down motion to paddle through the water, while the hind flippers are used for steering. These hind flippers can rotate forward, so that sea lions can move rather quickly on land as well. True seals have small pectoral flippers that are used for steering. When swimming, they paddle by moving their hind flippers from side to side. Because their pectoral flippers are so short, true seals don't move very well on land. They lumber along, dragging their rear flippers behind. True seals have no external ear flaps. Years ago, there were no laws protecting marine mammals such as seals, sea lions, and whales. They were hunted extensively for food and for their blubber, whalebone, teeth, or fur. However, in 1972 Congress passed the Marine Mammal Protection Act, making it iliegal to kill, harm, or capture any marine mammalwithout a permit. Now the only enemies of pinnipeds in the channel are sharks and killer whales. |
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The Channel Islands region is home to great numbers of true seals and eared seals. At one time, six different species of pinnipeds had rookeries in the Channel Islands region. However, today only four species regularly breed here. The most commonly seen pinniped along our coast is the California sea lion. These eared seals like to haul out onto floating channel buoys near harbors. Some even come into the harbors along with the boats. The males are usually about 8 feet long and weigh anywhere from 500 to 1,000 pounds. Light brown in color, California sea lions look black when wet. Most people have enjoyed watching these curious and playful creatures performing in circuses and oceanariums such as Sea World. Oceanariums have special permission to keep these marine mammals. Northern fur seals inhabit waters well off the coast. Consequently, these eared seals are seen less frequently than the California sea lion. Males often measure eight feet long and weigh up to 700 pounds. The northern fur seal has beautiful dark brown fur, which made it quite popular with fur hunters. In fact, this species was nearly hunted to extinction. The Steller sea lion is the largest eared seal in the Northern Hemisphere. Males often reach lengths of 13 feet and weigh up to a ton! This yellowish brown sea lion has a broad face and a thick neck. These animals are seen rarely in the Santa Barbara Channel and no longer breed here. Another species no longer breeding in the region is the Guadalupe fur seal. Individuals are sometimes seen off San Miguel Island, but most are found near the island of Guadalupe off the coast of Mexico. This eared seal is distinguished by its long, thin nose. The monstrous northern elephant seal often reaches 16 feet in length and weighs more than 5,000 pounds! The enormous size of these true seals, along with the huge, trunklike nose of the male, make the species easy to identify. During the mating period, males try to achieve dominance over the other males at the breeding grounds. In noisy displays of agression, they trumpet through their inflatable noses, trying to intimidate one another. The speckled harbor seal is found around the Channel Islands bobbing about in the kelp beds. These small true seals weigh about 300 pounds. They tend to be shy and less social than other species of pinnipeds. |
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Baleen whales are called mysticetes (MISS tuh seets), or "whales with a mustache," because of the baleen plates that hang in rows from the whale's upper jaw. These comblike plates are made of keratin (KEHR uh tin), the same material in fingernails and claws. The fringed edges of these horny plates are twisted together on the inside of the mouth to form a thick, netlike mat. Baleen whales are among the largest animals that ever lived on the earth, yet they eat some of the ocean's smallest creatures, plankton, microscopic plants and animals that are plentiful in the ocean. They also enjoy fishes such as sardines, anchovies, mackeral, and herring. Whales use their baleen to strain food: they open their mouths and take in a huge amount of water, and then, with their three-ton tongues, force the water out through the baleen, and swallow the tiny plankton left behind. Some of the larger mysticetes eat thousands of pounds of plankton every day! Besides the baleen plates, other features distinguish baleen whales from toothed whales. The blowholes on their heads have two openings, rather than one. In contrast to the extremely social toothed whales, mysticetes are known to be solitary animals. When migrating, they travel alone or in very small groups. |
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The California gray whale migrates farther than any other mammal. They sometimes travel more than 11,000 miles each year! During the summer, gray whales feed in the polar seas. When ice returns to these northern waters, they leave their feeding grounds and begin their southward migration to the shallow lagoons of Baja California to calve. California gray whales grow to a length of about 40 feet and may weigh up to 40 tons. They are dark gray, mottled with light grayish-white. Some of these light spots are barnacles imbedded in the skin of the whales. Others are simply barnacle scars. Among the barnacles are several species of whale lice, lending an orange color to the white patches. Gray whales have no dorsal fin, but do have a ridge of bumps, or knuckles, down their backs near the tail. California gray whales are the only baleen whales that are "bottom-feeders." Scientists believe they use their beaklike snouts, called rostrums, to create shallow craters in the ocean floor. They filter through the muddy waters, vacuuming up the crustaceans they have plowed up. Then, with their tongues, they push out the water and silt, leaving the food behind. Because they swim so slowly and so close to the California shore, gray whales have always been an easy target for whalers. In the 1800s and again in the 1930s, they were hunted almost to extinction. Since 1947, they have been protected by international laws. As a result, the population of California gray whales has now grown to more than 20,000! Here is a diagram of a gray whale's external features:
Match the numbers on the diagram to the features in this list:
Here is a diagram of a gray whale skeleton:
Match the numbers on the diagram to the features in this list:
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Each November the world's longest migration begins. After spending four or five months feeding in the northern Bering Sea, the California gray whales make their way south to the warm lagoons of Baja California to breed and calve. This round-trip journey takes them more than 11,000 miles! In their summer feeding grounds, gray whales consume hundreds of pounds of amphipods each day. Their blubber grows to a thickness of 6-12inches. Traveling at a speed of about 5 miles anhour, they swim from 20 to 100 miles, day and night, until they reach Mexico. The gray whales feed much less than normal during their long journey and at the breeding grounds. instead, they rely on their thick layer of blubber for energy. Once they reach the warm lagoons of Mexico, calving, courting, and mating occur. A female generally mates one winter, gestates a year or more, and calves the following winter. Cows with newborn calves stay in the lagoons until late winter to give the calves time to develop a layer of blubber that will protect them on the long journey north. On the return trip back to their summer feeding grounds, gray whale calves swim next to their mothers on the coastal side for protection. Use an atlas to help you locate the following items on the map at left:
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Although they share the same environment, there are important differences between fish and whales.
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Decapods are crustaceans with ten legs or arms such as crabs, lobster and crayfish. The word decapod comes from the Latin word decapoda meaning, not surprisingly, "ten feet." While certain ten-limbed mollusks, such as squid and cuttlefish, can also be described as decapods, here we're focusing on crabs. Here's a short list of common crabs and their unique features: Masking Crab Kelp Crab Flat Porcelin Crab Rock Crab Striped Shore Crab |
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If you find a crab molt on the beach and look at its underside, you can tell if it was from a male or a female crab simply by studying its tail. Crabs have tails? Yes. It's easy to see the tail on a lobster or a shrimp. But crabs keep their tails tucked up beneath them. On the male crab the tail is slender and pointed, while on the female it is broad and rounded. |
