Can you identify these animals with shells?

By: Maria Trimarchi
Image: Shutterstock

About This Quiz

In the animal world, if you're not fast, agile or strong, you'll be prey in to time. To survive the dinner hour, many animals have evolved hardened exteriors to protect themselves. Some of these strong exteriors, or shells, can grow with the animal so it will never be vulnerable if shed. An example would be the armadillo, whose shell is attached to its vertebrae. As the vertebra grows, so does the shell!

For other land animals with vertebrae, the shell can be so heavy they move slowly under the weight. Thus, like the tortoise, it must hide its extremities inside its shell until the predator goes away hungry.  Then there are those animals that use spikes to protect themselves, like the porcupine. A porcupine quill is a large 'hair" that has a hard, shiny shell and an elastic, honeycomb-like core.

Surprisingly, there are even more ways that shells have evolved. Crocodiles have thick, bone-like scales on the outside of their bodies to protect them ... but with those ferocious jaws, the scales seem like overkill. And then of course, you'll find a huge variety of animals that protect their soft bodies under the water with a hard shell. Find out all about the creatures that call a shell their home.

Take the trivia quiz right now. No protection needed!

Adult painted turtles can live to be 55 years year old - and that's in the wild, where habitat loss and accidents can reduce their lifespan. They love to bask in the sun; in the wintertime, they hibernate (usually in mud).

Of all the types of shrimp, the pink shrimp is the one North Americans may be most familiar with -- they're fished for food, and are sold peeled, cooked, and frozen. They also contain an enzyme used in everything from filtering wine to wound treatment.

The nine-banded armadillo, also called the long-nosed armadillo, is originally from South America, and now also thrives in the southern U.S. It has an outer shell that covers its back, sides, head, and tail, as well as the outside of its legs. Its shell, which is attached to the armadillo's vertebrae, grows with the animal.

The garden centipede, a symphylan, has a shell-like outer exoskeleton. They live in damp soil, and if disturbed, are prone to biting (which can cause a painful, discolored, and swollen wound.)

Cuttles are cephalopods related to squid and octopus. These marine animals are masters at camouflage, and have a unique ability to change color -- for hiding, or to indicate their mood. Cuttlefish ink is mixed with pasta dough for a darkly-colored spaghetti, and it's been used as paint, in sepia photography, and in cosmetics.

The Devils Flower Mantis eats flies -- although it won't pass up any small flying insects, like mosquitoes, if they are around. It's one of the largest species of mantis, and a skilled hunter.

Hedgehogs are nocturnal mammals, and because they are covered in spines, they resemble - but are not related to - the porcupine (they're related to shrews, though). When they're frightened, hedgehogs apply the stop and drop rule: they curl into a ball. Although there used to be hedgehogs in North America, the genus Amphechinus has gone extinct.

You'll find the Atlantic sea scallop in the Atlantic Ocean, north of North Carolina and up to Canada. They have large shells, up to 9 inches long, but unlike oysters, they can't close their shell completely. Atlantic sea scallops are heavily fished -- in fact, more than 53 million pounds are harvested in the U.S. each year.

Crocodiles have thick, bone-like scales on the outside of their bodies. The American crocodile is typically greyish in color, and has a distinctive V-shaped snout.

Porcupines use their needle-like spines, called quills, to protect themselves against predators -- the quills detach in their opponent's flesh. They find the wood just below tree bark to be a delicacy, and they're able to knock down a tree with their snacking.

The giant African land snail can live up to 10 years, with the right conditions (mainly, food and good weather). It's one of the biggest gastropods living on land and is known to eat at least 500 different species of plants -- which is why it's listed as one of the top 100 invasive species in the world.

Because deer ticks are no bigger than a sesame seed, they may seem harmless (you won't even feel one bite you). But these tiny arachnids are known to carry disease-causing pathogens, including the bacteria that causes Lyme disease. In the eastern part of the United States, they're the only carrier of the Lyme pathogen.

These small crabs are decapod crustaceans, but unlike other crabs that have hard shells, the hermit crab's abdomen is soft and spirally curved. And that's because the hermit crab finds its shell, rather than growing it. As they grow, they change shells to fit -- and they aren't above fighting another for the shell they want.

The black scorpion isn't an insect -- it's an arachnid. While their sting isn't considered lethal, their strong stinger is considered as powerful as a hornet's. They're territorial and are known to be aggressive, even toward other black scorpions.

The nautilus has remained unchanged over 400 million years, and they're called living fossils because of it. They're the only living cephalopod with a fully-developed spiral shell, and they have more tentacles -- more than 90 -- than others, such as the octopus.

Barnacles are what are known as "encrusters" because they permanently attach themselves via a stalk to a hard surface. The most common, called an acorn barnacle, grows six hard plates of body armor from calcium carbonate and uses its legs, called cirri, to trap its food, plankton.

The ironclad beetle, Zopherinae, has one of the hardest shells -- exoskeletons -- of all arthropods. They are considered "living jewelry" in some countries, including Mexico, where they're decorated with small gems and worn as brooches.

Periwinkles are related to limpets and whelks and are considered food in many countries. You'll find these small snails on the shore, on stones and rocks in tidepools -- unless ducks, who favor them, have already eaten them.

The shell of the abalone is composed of calcium carbonate tiles that are layered like bricks. It's very colorful on the inside, and is often used in in decorative inlays and decor.

Unlike humans who have iron-rich red blood, copper in lobster blood makes theirs blue. Similarly, their shells aren't red, although they appear to be when you order your favorite dish -- but it doesn't turn red until it has been cooked.

Chitons are rock-dwelling mollusks with a snail-like body in an articulated shell. It is composed of eight separate plates, allowing for both protection and flexible protection. Chitons are known to curl into a ball if not on their rock.

Horseshoe crabs have a long history, about 450 million years, on our planet. They are considered living fossils. They have a sharp tail, which isn't used as a weapon but mostly for the crab to right itself if overturned.

Seahorses are bony fish, but unlike most other fish, they don't have scales -- they have bony plates that are covered with skin, like segmented body armor. Another unique aspect of the seahorse is that it's the males who carry the developing eggs until they hatch.

Grasshoppers have been around for 250 million years. These plant eaters have been used as food, but they can also be a pest to humans. They are known to swarm and destroy vegetation and crops.

The sea urchin is found across the ocean floors worldwide, but rarely in the colder, polar regions. Sea urchins are commonly found along the rocky ocean floor in both shallow and deeper water. They are also commonly found inhabiting coral reefs.

Razor Shell Clam is a bivalve of the family Pharidae. It is found on sandy beaches in Northern Europe and Eastern Canada. The shell is smooth on the outside and whitish in color, with vertical and horizontal reddish-brown or purplish-brown markings separated by a diagonal line.

Cockroaches are an ancient group, dating back at least as far as the Carboniferous period, some 320 million years ago. They seek damp spots created by leaky pipes, and they're also attracted to grease and other food waste.

Wellfleet oysters tend to be long and strong-shelled. Experienced tasters know that they are plump and clean with a distinctively good balance of creamy sweetness and brine.

The Texas horned lizard, also known as Phrynosoma cornutum, is one of about 14 North American species of spikey-bodied reptiles. The Texas horned lizard is the largest-bodied and most widely distributed of the roughly 14 species of horned lizards in the western United States and Mexico. The average Texas horned lizard is 69 mm (2.7 inches) from snout-vent length

Giant tortoises are characteristic reptiles that are currently found on two groups of tropical islands: the Aldabra Atoll in Seychelles and the Galapagos Islands in Ecuador (a population at the Mascarene Islands was exterminated by the 1900s). These tortoises can weigh as much as 417 kg (919 pounds) and can grow to be 1.3 m (4 feet 3 inches) long. Giant tortoises originally made their way to islands from the mainland.

When we're talking about the queen conch, it could be the marine mollusc, or it could be just its shell alone. Queen conch is a large snail that can grow up to about a foot long, and lives up to about 40 years.

Known as the spiny anteater, the echidna is a prehistoric puzzle to scientists. Like the platypus, this mammal lays eggs. It has a good sense of smell and an acute sense of hearing, and powerful short legs for digging. For protection, its back and sides are covered with spines, which give it camouflage among bushes and brush.

Despite their appearance, these arachnids are more closely related to scorpions than to spiders. And that thing about daddy longlegs being poisonous? They don't have venom -- or fangs.

Unlike others in the octopus species, the female argonaut uses a shell to house her young -- but that's not all it's good for. This paper-thin shell is also a ballast tank, in which air trapped at the surface is used by the Argonaut to bob, effortlessly, through the water.

The giant clam is the largest living bivalve mollusk, which means it has two shells connected with a hinge -- but the adults are the only clams that can't completely close their shells. They can grow to be 4 feet in size, can weigh more than 440 pounds, and can live to be more than 100 years old.

These small "devils" are also known as the thorny dragon or the mountain devil. Australia's thorny devil is a spiky lizard that lives on black ants, and knows how to pull water out of sand when it's thirsty.

Millipedes aren't worms, nor do they have a thousand legs as their name suggests. They're arthropods with a segmented body and an exoskeleton. They curl into a ball when they feel threatened, and won't bite you, but they do secrete a smelly fluid that could irritate your skin.

The Busycon whelk has what's called a siphonal canal, which is an anatomical part of the shell that siphons water into the central cavity. These large edible sea snails are marine gastropod mollusks, and sometimes mistakenly called "conchs" in the U.S. because of the appearance of their shells.

The scientific name for the Indian rhinoceros is Rhinoceros unicornis, and it's the second largest member of the rhino family. Despite being able to charge an opponent at 30 mph, the Indian rhino is hunted by humans for its prominent horn, considered medicinal in some countries and ornamental in others.

The blue crab, named because of its bright blue claws, is also called the Atlantic blue crab or, in the Chesapeake region, the Chesapeake blue crab. This crustacean grows to about 1 to 2 pounds and eats pretty much anything it thinks looks delicious.

Despite how it's spelled, the correct pronunciation of this clam, which is native to the Pacific Northwest, is "gooey-duck." It's the largest burrowing clam in the world, and the longest living animal -- it can live up to 140 years.

You might call it a crawfish or you might call it a crayfish; it's the same thing -- and is also known as the Louisiana crawfish, Louisiana crayfish, or mudbug. The Red Swamp Crawfish is native to the south central United States, through the Gulf States and the Florida panhandle, and is known as an invasive species.

Krill, only about 2 inches big, are known to eat single-celled plants and phytoplankton near the surface of the ocean. But they're also the main food staple for whales, fish, birds, and hundreds of other species.

Many species live in the soil beneath our feet and oribatida, which is also known as the beetle mite or the moss mite, is one of them. In fact, it's the most common arthropod to live in soil. Beetle mites are also host to tapeworms -- and can pass them along to you, or your pets.

Mussels are bivalve molluscs, which means their soft bodies are protected by two shells connected with a hinge. They can be found as marine mussels, which live in salt water, and as freshwater mussels, which live in rivers, lakes, and ponds.

The Giant Prickly Stick Insect can't bite or sting, but it has a well-developed passive defense: camouflage. They're known to strike a scorpion-like "threat pose" when threatened and are able to pinch their opponent with sharp spines located on their rear legs -- sharp enough to pierce your skin.

Mantis shrimp have been called "sea locusts," "prawn killers," and "thumb splitters," and are capable of inflicting some serious damage to their prey, to you, and even to aquarium glass, with their claws. At a velocity of 10 meters per second, the power of their punch is similar to that of a .22 caliber bullet. There are about 400 species of these marine crustaceans, and although they're aggressive, they spend most of their time hiding in the sea bed.

The Hawaiian Blackfoot, also known as black-foot opihi, is an edible limpet -- an aquatic snail with a conical shell. While limpets can be found in many places, these are only found in the Hawaiian Islands. Unlike others that resemble it, limpets are able to move from place to place rather than attaching permanently to a surface.

Scaphopods are the only mollusks that look like tiny tusks, and are often called "tusk shells" because of it. They live in the sand, buried head-first, and throughout history, have been used for jewelry, money, and more.

Pangolins are the only mammals known to have protective scales made of keratin (just like your fingernails) covering their bodies. They're currently a threatened species because of deforestation in their natural habitats, but also because they're the most hunted and trafficked mammals in the world -- mainly for their meat and scales.

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