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Today's Wonder of the Day was inspired by Maya from Fairfax, VA. Maya Wonders, " How many teeth do sharks have? " Thanks for WONDERing with us, Maya!

"Say cheese!" That's what you might say to a shark if you were trying to take an underwater in the ocean. After all, sharks have all those nice shiny teeth. Their smiles must make for great photos, right?

What? You wouldn't want to take a with a shark? Why not? Oh...all those sharp teeth...right. Gotcha. So just how many teeth do sharks have anyway?

As you might , the number of teeth a shark has depends upon exactly what type of shark it is. There are many, many different types of sharks in the world's oceans, and the number of teeth they have can vary greatly.

For example, great white sharks have approximately 50 teeth at any one time (their "" teeth). Like most sharks, however, they have rows of teeth in development that are ready to take the place of teeth that fall out. Some sharks have over 300 teeth in various stages of development within their mouths at any one time!

Unlike human teeth, shark teeth are not very strong and tend to fall out easily. It's not a big deal for sharks, because they are constantly producing new teeth to replace the ones they lose. In fact, some sharks can have over 50,000 teeth over the course of their lives!

Many sharks have teeth in rows. Both their upper and lower jaws can have 2-3 or as many as 15 such rows. Their teeth do not have roots, so they break off easily and may last as little as a week. New teeth can move to replace lost teeth within a day to a couple of weeks. The skin within a shark's mouth moves new teeth into position like a belt.

Although it might sound like a bad thing to be constantly losing teeth all the time, this system works well for sharks. Over history, sharks have developed extremely strong jaws that give them the bite that makes them the predators of the oceans.

When they bite into a tasty meal, they usually lose several teeth. If they couldn't replace those teeth easily, it would do them no good to have such a bite. So the ease with which they can replace teeth has actually helped sharks to develop the strong bite that defines them.

Since sharks go through so many teeth over the course of their lives, fossilized shark teeth can be easy to find along the shores of many beaches. Shark tooth hunting has become a popular for visitors to beaches with shark teeth.

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Today's Wonder of the Day may leave you WONDERing why you don't see more toothbrushes in the ocean!

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Today's Wonder of the Day was inspired by Mackenzie. Mackenzie Wonders, " How many sharks are in the ocean? " Thanks for WONDERing with us, Mackenzie!

How many stars are in the universe? How many fish are in the sea? Can these things even be counted? Or does the answer approach ?

How about one type of fish, like the shark? Surely we could get an of just the sharks, right? Actually, probably not!

There happen to be so many different types of sharks that it would be impossible to them all. There could be a billion or more sharks in all the oceans around the world.

Up until the 16th century, called sharks "sea dogs." Today, scientists believe there are more than 400 different of sharks in the world.

The smallest of these - the dwarf lanternshark - is less than seven inches long. The largest - the whale shark - can grow as long as 60 feet, making it the largest fish in the world. (Remember: Whales are mammals, not fish!)

Scientists believe that sharks are older than dinosaurs. The earliest known sharks existed more than 450 million years ago.

Unfortunately, it is rare to find complete fossil remains of sharks. This is because sharks don't really have .

Instead, they have skeletons made of , which is a kind of connective enough to give support but than bone. Humans have in their ears and noses.

Sharks can be found in all seas around the world. Most sharks live in saltwater, but a couple of - bull sharks and river sharks - can live in freshwater or saltwater.

Unfortunately, many shark are under attack and are decreasing in numbers every year. Experts estimate that 100 million sharks are killed by people each year.

Sharks are eaten as seafood in many areas, including Japan and Australia. Commercial and recreational fishers are believed to be responsible for the populations of some shark .

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Today's Wonder of the Day was inspired by Mackenzie. Mackenzie Wonders, " How many sharks are in the ocean? " Thanks for WONDERing with us, Mackenzie! How many stars are in the universe? How many fish are in the sea? Can these things even be counted? Or does the answer approach ?

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Today's curious question doesn't have an easy answer. Although many people believe that frogs and toads are completely different creatures, the truth is a bit more complicated .

Scientists animals and plants based on various characteristics . Frogs and toads are both members of the same - Amphibia - which means that they're both amphibians.

Amphibians are cold-blooded vertebrates that spend the early part of their lives in water (breathing with ) and the rest of their lives on land (breathing with ).

Moreover, frogs and toads are also both members of the same - Anura - which means that they're closely related and share many similar characteristics .

There are hundreds of individual of frogs and toads within the Anura . However, the many within the Anura can appear quite different, leading people to believe that toads and frogs aren't the same.

The popular distinction drawn between frogs and toads is probably best viewed as a distinction between true "frogs" (members of the Ranidae ) and true "toads" (members of the Bufonidae ). The Ranidae contains more than 400 of frogs, while the Bufonidae contains more than 300 of toads.

Frogs can look and act quite differently from toads. Here are some of the differences you may notice:

Frogs:

Need to live near water to survive.

Have smooth, moist skin that may look or seem .

Have a narrow body with round eyes that .

Have long hind legs that help them take long, high jumps.

Have many predators.

Toads:

Don't need to live near water to survive.

Have rough, dry, bumpy skin.

Have a wide body with oval eyes that don't as much as frogs' eyes.

Have short hind legs that allow them to take small hops rather than jumps.

Don't have many predators because their skin has a bitter taste and smell that deters predators.

Before you become too confident in your ability to distinguish frogs from toads, though, remember that these differences don't hold true across all .

In fact, certain can fit into both categories. For example, it's possible to find a frog with bumpy skin or even a toad!

Near the , frogs and toads can look quite similar. Sometimes, the only way to tell them apart is to look inside them at things like their teeth and bones. Good luck catching them, though!

If you do happen to catch a frog or a toad to get a closer look, don't worry about getting warts on your hands. Neither frogs nor toads will give you warts.

That's just a myth that probably came about because of the bumpy skin common to many toads. A toad's bumps aren't really warts. They're a special adaptation that helps it blend into its environment.

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Leap on over to Wonderopolis today and hang out at our pad. If you don't, you'll be green with envy. And we'll say, "We toad you so!"

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you're through the dense rainforest of South America. Along the way, you up at the trees in amazement. Later, you crouch down to get a better look at some bugs. A flash of color catches your eye and you realize it's a poison dart frog.

You're tempted to get a closer look at this amphibian but you WONDER, are poison dart frogs really that ? In this Wonder of the Day, let's find out!

There are many that make up the family of poison frogs native to Central and South America. These frogs tend to live amongst the leaves on the rainforest near ponds or streams, although a few live in the trees and never come down.

Poison frogs are known for their , vivid colors. You can find them in just about any color combination you can think of. The colors you're likely to see include red, black, yellow, green, blue, gold, copper, orange, silver, and pink.

These flashy colors make poison frogs stand out, but they don't make them easy prey. Instead, their coloring is a defense mechanism that protects them from predators. Their colors serve as a that their skin is , so it's best not to eat them. In order to be easily seen by potential predators, poison frogs are diurnal, which means they're mainly active during the day.

Exactly how are poison frogs? That can be hard to . Some are not at all. Most poison frog are considered but not deadly. The poison in their skin can cause swelling, nausea, and if touched or eaten without necessarily being fatal.

A few , however, are considered to be among the deadliest animals on Earth. For example, the golden poison dart frog has especially skin with enough poison to kill as many as 10 grown men.

The indigenous peoples of Colombia are known to dip the tips of their blowgun darts in this powerful poison when hunting. This practice is what gives poison dart frogs their popular name.

Each poison frog develops a unique kind of toxin, and scientists believe the poisons come from the frogs' diet, which can include various rainforest insects such as ants, beetles, centipedes, and termites. This is why poison frogs kept in zoos or in captivity are not . Without the unique diet provided by rainforest insects, these frogs never develop the poisons.

Although to humans and animals, frog poisons may soon provide medicinal benefits to humans. Scientists researching frog poisons believe they can be modified and turned into medicines to treat pain and heart and circulatory conditions.

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Even if you're looking for Prince Charming, you'll probably want to skip kissing the subject of today's Wonder of the Day!

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Today's Wonder of the Day was inspired by mark from Lockhart, TX. mark Wonders, " Do frogs hibernate? " Thanks for WONDERing with us, mark!

When Old Man Winter comes along, it's natural to stay indoors. After all, it can be dangerous to your health when the weather outside gets frightful. But what about all the animals in the world?

You probably know that certain animals decide to hibernate for the winter. Large furry bears find a place where they can stay reasonably warm and simply go into a deep sleep-like state for several months. Other animals, such as birds, migrate to a warmer climate. Not all animals can migrate or hibernate, though.

Take frogs, for example. They don't have thick skin and fur like a bear. They also can't take to the skies to fly south for the winter. Yet, some frogs, such as the wood , live all over the United States and even as far north as Alaska and above the Arctic Circle. How do these little creatures the temperatures in these areas?

Recently, scientists have studied wood frogs and discovered some amazing things about these unique animals. So what do wood frogs do when the temperature drops below the freezing mark? They !

As the September air gets colder and colder, wood frogs that live in the woods take cover under layers of leaves and other ground cover. Then something miraculous occurs: they stop breathing, their hearts stop beating, and their stops flowing. Eventually, they .

About two-thirds of the in their bodies turns to ice. To the naked eye, they appear dead. They don't move. If you tried to bend one of their arms, it would break. Yet life still exists deep inside.

To study wood frogs in freezing environments, scientists attached tiny radio transmitters to a group of frogs. The transmitters allowed scientists to track their movements and study them in their frozen state when they made their homes for the winter.

Over the course of two years of study, not one of the frogs died. Scientists learned that the frogs could withstand temperatures as low as 0º F for as long as seven months. These findings surprised scientists, who had previously believed that these frogs could only for a few weeks in warmer temperatures.

Scientists discovered that the inside individual cells does not , but the in between cells does solid. Cells still , but they can't communicate with each other.

Wood frogs have special nucleating proteins in their that cause the in their to first. Cells begin to as ice draws out of nearby cells. This process could result in death if it weren't for a substance that acts like antifreeze within cells.

Scientists believe early / cycles help wood frogs to convert stored in their livers into in their cells. They think high levels of inside cells allow wood frogs to being frozen for so long, because the keeps sufficient inside cells to keep them alive.

Amazingly, when spring temperatures arrive, frozen wood frogs slowly out. Their hearts start beating, their starts flowing, and they begin to breathe again. gets converted back to , and they're eventually able to hop away to the nearest pond or lake to start the mating process.

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Today's Wonder of the Day was inspired by mark from Lockhart, TX. mark Wonders, " Do frogs hibernate? " Thanks for WONDERing with us, mark! When Old Man Winter comes along, it's natural to stay indoors. After all, it can be dangerous to your health when the weather outside gets frightful.

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Watch a shark swim

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Underwater Shark Great White Sharks Underwater Shark Swimming deep in the Ocean

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Underwater Great White Sharks Swimming deep in the Ocean Huge shark swimming in the deep underwater.

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Watch a whale shark eat plankton and breathe underwater with gills.

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Whale Shark feeding on plankton in the Maldives, June 2012

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Hammerhead shark facts and pictures

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A hammerhead shark uses its wide head to trap stingrays by pinning them to the seafloor. The shark's eye placement, on each end of its very wide head, allows it to scan more area more quickly than other sharks can. The hammerhead also has special sensors across its head that helps it scan for food in the ocean. Living creatures' bodies give off electrical signals, which are picked up by sensors on the prowling hammerhead.

The shark hunts alone, and can find stingrays that hide under the sand on the seafloor. Hammerheads also eat bony fishes, crabs, squid, lobsters, and other sea creatures. The upper sides of these fish are grayish-brown or olive-green and they have white bellies. They have very impressive triangular, serrated teeth-like the edge of a saw's blade. Hammerheads' mouths are on the underside of their heads.

Unlike many fish, hammerheads do not lay eggs. A female gives birth to live young. One litter can range from six to about 50 pups. When a hammerhead pup is born, its head is more rounded than its parents'.

There have been very few recorded attacks on people by the great hammerhead.

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This shark's unusual name comes from the unusual shape of its head, an amazing piece of anatomy built to maximize the fish's ability to find its favorite meal: stingrays. A hammerhead shark uses its wide head to trap stingrays by pinning them to the seafloor.

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Great white shark facts and pictures

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When a great white shark is born, along with up to a dozen siblings, it immediately swims away from its mother. Born on the east and west coasts of North America, the south of Africa and southwest Australia, baby sharks are on their own right from the start. Their mother may see them only as prey.

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When a great white shark is born, along with up to a dozen siblings, it immediately swims away from its mother. Born on the east and west coasts of North America, the south of Africa and southwest Australia, baby sharks are on their own right from the start.

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Watch an underwater photographer take pictures of sharks

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Dive into the wild world of sharks with the Nat Geo photographer and explorer Brian Skerry. You'll get up close to learn the truth behind these fantastic, ferocious fish with The Ultimate Book of Sharks. Flip through a gallery of pics from the book. Then check out shark games and videos!

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Poison dart frog facts and pictures

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With a range of bright colors-yellows, oranges, reds, greens, blues-poison dart frogs aren't just big show-offs either. Those colorful designs tell potential predators, "I'm toxic. Don't eat me." For example, the golden poison dart frog has enough poison to kill 20,000 mice. Scientists think that poison dart frogs get their toxicity from some of the insects they eat.

How do poison dart frogs capture their prey? Slurp! With a long, sticky tongue that darts out and zaps the unsuspecting bug! The frogs eat many kinds of small insects, including fruit flies, ants, termites, young crickets, and tiny beetles, which are the ones scientists think may be responsible for the frogs' toxicity.

Poison dart frogs live in the rain forests of Central and South America.

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These frogs are considered one of Earth's most toxic, or poisonous, species. For example, the golden poison dart frog has enough poison to kill 20,000 mice. With a range of bright colors-yellows, oranges, reds, greens, blues-they aren't just big show-offs either. Those colorful designs tell potential predators, "I'm toxic.

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Frog photos. Click the full-screen button to see and read captions about different kinds of frogs.

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Hop to it and check out a few ribbit-ing photos of these totally awesome amphibians.

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Red-eyed tree frog facts and pictures

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A female red-eyed tree frog has laid a batch of eggs on a leaf. She chose the spot carefully-the leaf hangs over a pond.

When the eggs are ready to hatch, the tadpoles inside start swirling around vigorously. The activity breaks each egg open, releasing the little tadpoles. All the tadpoles wash down the leaf in a little stream of moisture from the hatching eggs, and-plop! plop! plop!-they land in the pond below.

Feeding on tiny insects, the tadpoles live in the water they fell into until they metamorphose, or develop, into little brown froglets. At this point they leave the water and climb up nearby trees to live as tree frogs.

By the time they're adults, the frogs have turned a striking green, with blue-and-yellow striped sides, orange or red feet, a flash of blue on their thighs, and big red eyes. The bright colors are a defense mechanism.

Being green helps the red-eyed tree frog blend in with tree leaves. If the green camouflage fails and a predator spots a sleeping frog, it swoops in for what it thinks will be a tasty meal. But the awakened frog's eyes pop open, revealing their startling bright red color!

Also, when the frog rushes to get away, it untucks its brightly colored legs. The predator is often so surprised by these sudden flashes of color that it is momentarily confused and hesitates. And while it does, the frog has a split second to make its escape!

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A female red-eyed tree frog has laid a batch of eggs on a leaf. She chose the spot carefully-the leaf hangs over a pond. When the eggs are ready to hatch, the tadpoles inside start swirling around vigorously. The activity breaks each egg open, releasing the little tadpoles.

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Frogs swimming and jumping to catch their prey

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Glass frog facts and pictures

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A small frog the length of a quarter leaps from one plant leaf to another, flaunting its little belly as it soars. The skin on the frog's underside is see-through. So as the amphibian jumps you can view some of its internal organs, including its beating heart.

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A toad swimming and walking

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Bullfrog croaking

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Today's question might sound a little odd. But let's face it. If you have an octopus, you'll probably need to hide it. After all, most parents and teachers aren't going to let you walk around with an octopus.

Some people find octopuses frightening. With their eight and huge heads, they do look a little scary. Their soft bodies, though, are a tasty meal for many . Sharks and stingrays are just a couple of animals that crave octopus for dinner. Luckily, octopuses are really good at hiding themselves.

Those soft, boneless bodies allow octopuses to change shape. Octopuses also have special skin cells full of yellow, red, brown and black . This allows them to change color. Octopuses learn at an early age how to their muscles to change both their color and their shape.

How do octopuses hide? They change to look like something else. Sometimes, they flatten their bodies to look like the smooth sea floor. Other times, they change to look just like a coral reef. Octopuses are even able to take on the color of their surroundings despite being color blind! Isn't it amazing how creatures can learn to hide from their enemies?

All octopuses can camouflage themselves. But one particular kind of octopus is very good at hiding. Called the octopus, it can copy the form of many different species.

Scientists first found the octopus in 1998 off the coast of Indonesia. The animal has since been spotted in the waters of Malaysia, as well. The octopus lives in open waters and hunts during the day. For this reason, it doesn't have many places to hide from .

Instead, this special octopus has learned to hide in plain sight. It does so by changing shape and color to look like other animals. In total, scientists believe the octopus can imitate up to 13 different species. This includes jellyfish, anemones, and mantis shrimp. The octopus can also change to look like lionfish and sea snakes.

Can you imagine that? One minute, you're looking at an octopus. The next minute, it's a lionfish. You blink, and now it's a jellyfish. You rub your eyes to make sure you're not seeing things. The octopus is now a shrimp! You can see how the octopus confuses its .

The octopus doesn't just look like the animals it . It acts like them, too! For example, when a octopus wants to look like a sea snake, it copies the snake's movement. It sticks out two of its arms and moves them in opposite directions. This scares away would-be pretty quickly.

Do you think you could find a octopus in the ocean? You'll need to look closely. They're great at hiding anywhere. Could that jellyfish really be an octopus? How about that piece of coral? You might see one without knowing it!

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Today's question might sound a little odd. But let's face it. If you have an octopus, you'll probably need to hide it. After all, most parents and teachers aren't going to let you walk around with an octopus. Some people find octopuses frightening. With their eight and huge heads, they do look a little scary.

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Facts and pictures

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Most octopuses stay along the ocean's floor, although some species are pelagic, which means they live near the water's surface. Other octopus species live in deep, dark waters, rising from below at dawn and dusk to search for food. Crabs, shrimps, and lobsters rank among their favorite foods, though some can attack larger prey, like sharks. Octopuses typically drop down on their prey from above and, using powerful suctions that line their arms, pull the animal into their mouth. The octopus performs its famous backward swim by blasting water through a muscular tube on the body called a siphon. Octopuses also crawl along the ocean's floor, tucking their arms into small openings to search for food. Seals, whales, and large fish prey on octopuses.

If threatened, octopuses shoot an inky fluid that darkens the water, confusing the aggressor. The octopus can also change to gray, brown, pink, blue, or green to blend in with its surroundings. Octopuses may also change color as a way to communicate with other octopuses. Octopuses are solitary creatures that live alone in dens built from rocks, which the octopus moves into place using its powerful arms. Octopuses sometimes even fashion a rock "door" for their den that pulls closed when the octopus is safely inside.

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Octopuses are sea animals famous for their rounded bodies, bulging eyes, and eight long arms. They live in all the world's oceans but are especially abundant in warm, tropical waters. Octopuses, like their cousin, the squid, are often considered "monsters of the deep," though some species, or types, occupy relatively shallow waters.

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Bullsharks

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Diving with Dangerous Bull Sharks | Deadly 60 | BBC Earth

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Frog defenses.

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The Glass Frog: Ultimate Ninja Dad | Animal 24

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A Sneaky Coconut Octopus Uses Tools to Snatch a Crab 🦀