How many sharks are in the world

We don't know everything We like how all of our Wonder Friends out there like you! Thanks so much for leaving us this SUPER comment, Haley, and for sharing all the awesome facts you learned about sharks today! We like learning about sharks, too! We're pretty sure that no one knows the exact number of sharks in the sea. There are so many different sharks swimming in so many different bodies of water! Maybe some day we will know for sure, though! Maybe some time in the future, someone will invent a special machine that locates, identifies and counts all the creatures in all the oceans!

There are many, many different types of sharks, including Great Whites, in the oceans of the world. Because there are so many different sharks in so many different bodies of water, it would be impossible to count them all.

Can you believe there could be a billion or more sharks in all the oceans around the world? That's a LOT of sharks! Mac's Class! We're super glad you learned some new things about sharks today! You taught US something, too! We learned that there is a show called Dolphins of Shark Bay! It's about a group of dolphins who live in a bay where a LOT of sharks live and eat!

Thanks so much for sharing your shark story, Nmb! Hi, Kadoodle! There are many reasons why people kill sharks, but one of the main reasons is to eat them. In many parts of the world, people eat sharks. Some cultures even use parts of a shark's body as a type of medicine. We're glad you visited Wonderopolis today and asked such a great question! That's a good question, Andrew!

We are undergoing some spring clearing site maintenance and need to temporarily disable the commenting feature. Thanks for your patience. Drag a word to its definition. You have answered 0 of 3 questions correctly and your score is:. Want to add a little wonder to your website? Help spread the wonder of families learning together. We sent you SMS, for complete subscription please reply. Follow Twitter Instagram Facebook. How many sharks are in the ocean? How many different species of sharks are there?

What is the largest shark? Wonder What's Next? Try It Out Are you ready to learn more about sharks? Check out the following activities with a friend or family member: Check out the Monterey Bay Aquarium's Open Sea Webcam for a sneak peek at some sharks. How many sharks do you see? Can you identify what type they are?

Would you like to swim with sharks? Why or why not? Have you ever watched Shark Week programs on Discovery? If you had a pool big enough to hold one, would you want a shark as a pet? Did you get it? Test your knowledge. What are you wondering? Wonder Words species infinity mariners cartilage connective tissue commercial recreational responsible reduced populations count bones strong softer accurate specific impossible Take the Wonder Word Challenge.

Join the Discussion. Sara Apr 1, Apr 16, That's a great question for a Wonder Journey, Sara. Let us know what you learn! Mikayla Pierce Jan 8, Do we know how many sharks we still have. Jan 8, Jan 15, That's a great question for a Wonder Journey. Turner Nov 13, Nov 13, Hi Turner! Thomas Nov 8, Nov 10, Hi, Thomas! You'll have to take a Wonder Journey to find that answer. Finnuth Sep 1, Sep 3, Nick May 31, I have nothing against Sharks, but why play favoritism?

Why is everyone concerned about Sharks and not other fishes it sea life like sea-horse, octupus. You know there are billion Sharks but not necessarily billion crabs, octupus, salmon etc They may also go extinct.

I love sharks all sharks and how can you not pick. Dec 12, Liesje Jul 10, Jul 11, And fish. Also friends, not food. Jun 4, Plus, sharks are scary. Pipper Apr 21, Apr 22, More than one? Rishita Aditya Mar 21, Alexa Dec 19, What is the different shark species in the world. Dec 19, Brenden Dec 17, Timothy cox Sep 21, Allyson May 15, Are sharks afraid of humans? If so why? My favorite type of shark is a great white shark because they are really cool. Feb 6, Thanks for sharing your thoughts, bea s!

Oct 8, Robert Nov 5, I think people like sea food with sharks in them probe. May 25, Kaileah May 15, May 21, May 24, May 14, Shane May 9, Charles May 7, Do sharks have lungs or gills?

They come up for air but in the water they don't blow bubbles or anything they are normal as if they have gills. May 9, Charles May 9, We're happy to help! Hi, sarai! Sharks do sometimes eat trash that is found in the oceans. HI my name is Michael and I think that Wonderopolis is the best website to learn something. Hi, Michael!

MartinAV24 Jan 18, I thought sharks were scary and horrible, but no there really just protect them selfs. Why do they call them sea dogs? Jan 22, Camposks24 Jan 18, I wonder how scientist find out about all these types of sharks? Jan 25, Becky Jan 18, I would recommend to answer your title question whickph is how many sharks are still leaving in the world, but in addition I liked the information you said.

Thanks, Becky! Anne Jan 5, I enjoyed reading the facts about sharks and it definitely worrys me that million sharks are killed each year but I also think it is important that we recognise that sharks and not primarily killed for food but rather are killed after being caught in nets for fish intended to be eaten - for every pound of intended fish caught 5 pounds of unintended fish are caught including dolphins, whales and sharks. With between billion sharks being bi-kill each year - however I still appreciate the work you are doing to inform people about this topic.

Jan 9, Alexandria Jan 4, Peter Oct 24, Oct 26, Aug 31, Tanner May 17, May 18, Dory Aug 29, Hi i'm dory and i have short term memory loss that is why they did a movie. Hi, Dory! Have you met the shark Bruce?? Josh Aug 18, Aug 20, The world is a pretty wonderful place, Josh!! Gavin Apr 11, Apr 12, Vivian Jan 4, I did not know that fisherman are the ones who are killing the sharks! But how? Jan 4, And who could forget Helicoprion , an ancient shark that had a whorl of teeth in its mouth like a buzzsaw.

But all good things must come to an end: million years ago the largest extinction event in Earth's history called the Permian-Triassic extinction event wiped out 95 percent of all living species on the planet, including many of these bizarre sharks. Only a few families of fish—food for large ocean predators like sharks—survived the Permian extinction.

But as the seas recovered, so did they. Ray-finned fish began to fill the seas, adapting to different habitats. And with them, their predators evolved too. During the Jurassic to million years ago and Cretaceous to 66 million years ago Periods, marine reptiles like ichthyosaurs, mosasaurs and plesiosaurs ruled the seas—along with some sharks. By the mid-Cretaceous, around million years ago, sharks that resemble large, fast-swimming modern sharks started to appear.

In , the fossilized remains of the foot meter shark Ptychodus mortoni , which swam the ocean 89 million years ago, were found in Kansas Kansas at that time lay under a vast inland sea. Only a jaw was found—a very big jaw—lined with hundreds of flat teeth that would have helped it crush shellfish.

Thus, despite its size, it was likely a slow-moving, bottom-dwelling shark. Around the same time lived the Ginsu Shark Cretoxyrhina mantelli —a slightly smaller shark, at 20 feet 6 meters long, but much more fearsome. The Ginsu is one of the better-known ancient sharks because paleontologists found a nearly complete fossilized spine for the species, along with very impressive teeth.

They were very sharp, 6 centimeters long, and likely used to kill and eat larger fish prey. Ginsu teeth have been found embedded in pleisiosaur and mosasaur bones, suggesting that they may have gone after small marine reptiles as well. Another group of sharks known as the crow sharks Squalicorax were smaller, at around one-third the size of the Ginsu.

Instead of ruling as fierce predators, crow sharks were likely scavengers that fed upon already-dead animals. Paleontologists think this because bones of large animals from this period have been found covered with crow shark bite marks. The Cretaceous—Paleogene extinction 65 million years ago wiped out the dinosaurs—but not the sharks. Approximately 80 percent of the shark, ray and skate families survived this extinction event.

Some of those that survived are the ancestors of the sharks alive today. In the 65 million years since the Cretaceous-Paleogene extinction, sharks have continued to evolve and become the diverse group of cartilaginous fishes we see today. Some modern sharks have direct ancestors from before the Cretaceous extinction event.

Cow sharks date back to million years ago, while the snake-like frilled sharks have fossils from 95 million years ago. That doesn't mean that these modern animals are identical to their ancient versions; on the contrary, they have certainly undergone evolution and changed over the millions of years of their existence.

But paleontologists are fairly certain that our modern sharks are directly related to extinct relatives known to us by fossils. The lamnoid sharks order Lamniformes —including the great white, mako and thresher sharks, among others—also can trace their lineage into the Cretaceous. But paleontologists don't have a good sense of which ancient sharks species evolved into modern lamnoid sharks. Their ancient ancestors left behind many fossilized teeth, but there isn't an easy way to put them in order without more information provided by fossilized skeletons.

One well-known extinct relative of modern lamnoid sharks is the Megalodon Carcharodon megalodon , which was more than 50 feet long with seven-inch teeth and lived 16 million years ago. It went extinct 1. For many years, some scientists believed that the Megalodon was an ancestor of the great white shark—but great whites are more closely related to ancestors of modern mako sharks.

It is likely that the Megalodon and great white sharks even coexisted, with the Megalodon feeding primarily on whales and the great white on seals. One notable feature of sharks is that large filter feeders evolved separately multiple times. Between 65 and 35 million years ago, several sharks evolved away from predation and towards filtering tiny plankton out of the water for sustenance.

An ancestor of the modern-day carpet sharks evolved into the whale sharks Rhincodon typus we see today, while two ancient ancestors of the mackerel sharks evolved into basking sharks Cetorhinus maximus and megamouth sharks Megachasma pelagios. The shark family that evolved most recently is that of hammerhead sharks Sphyrnidae , which first appeared 50 to 35 million years ago. Sharks are found in waters throughout the world, from shallow water to the deepest parts of the ocean.

Some species migrate vast distances, moving between various locations to breed and find the best sources of food. Some of these migrations are fairly easy to track. For example, every winter in Florida, blacktip sharks head from the open ocean to the shore where they mate and breed.

Thousands of these sharks migrate at once and come close to shore, making it easy for people to spot them and scientists to study them. But sharks migrating far offshore and traveling individually are more difficult to track. To make up for this, scientists are using tagging and tracking technologies to learn about their movements. They will often place a computerized tag on the back of a shark that sends information about its GPS location back to the scientists on land.

New tagging and tracking technology has also allowed researchers to get a better idea of where the gentle whale sharks go after gathering to feed on plankton off the coast of Central and South America. Even so, new populations continue to be discovered , showing how much we still have to learn about the biggest of all sharks. Several shark species also migrate between deeper and shallower water every day; these migrations are called diel vertical migrations.

The distance of these daily migrations range from 30 to feet tens to hundreds of meters depending on the shark species. Blue sharks Prionace glauca , for example, spend their nights near the ocean's surface top feet or meters , but will dive down to depths of feet meters —and occasionally deeper to feet meters —and back to the surface throughout the day.

One of the biggest changes when moving between depths is the temperature. It's likely that the sharks are willing to put up with such cold temperatures in order to hunt deep-water prey like squids and octopods, and then return to the surface to warm up again.

Other sharks like the lesser-spotted catshark Scyliorhinus canicula spend their days in deeper water 65 feet or 20 meters , but swim to the surface at night —probably to keep warm. Shark lifespans are not well known and vary quite a lot among species.

Scientists figure out the age of most species of fish by counting the "rings" on their otoliths tiny calcium carbonate structures in their ears like the rings on a tree. But this isn't so easy for sharks because their otoliths are the size of a grain of sand and are thus very difficult to see. Another method measures the growth of shark vertebrae using similar "rings," but how frequently the rings are laid down varies from species to species, making that method unreliable.

Recently, scientists have been using a new method of determining shark age: by using a radiocarbon timestamp found in the vertebrae of sharks left over from nuclear bomb testing in the s and s. For example, the oldest male great white shark was 70 years old , and the oldest female was 40 years old.

That is much longer than previous estimates of about 20 years. Similarly, sand tiger sharks Carcharias taurus were found to live up to 40 years , which is 11 years longer than expected. Sharks grow and mature slowly and reproduce only a small number of young in their lifetimes. Unlike most bony fish, they put a lot of effort into producing a small number of highly developed young at birth rather than releasing a large number of eggs that have a high probability of not surviving.

Because of these traits, sharks are particularly susceptible to overfishing. All sharks produce young through internal fertilization. A male shark does not have a penis. He has two claspers on the rear of his underside, attached to his pelvic fins, which he inserts into a female shark to deliver sperm to her eggs. Typically the male will only use one of his claspers at a time, depending on the pair's position although some shark species may use both claspers.

Sometimes they mate side by side, while other times the female will lay upside down. There are also several cases of internal asexual reproduction in sharks, a phenomenon called parthenogenesis. This occurred when a captive female shark isolated from males had a shark pup. There are three different ways that a baby shark can be born once a female shark has a fertilized egg, depending on the species. Viviparity is when a shark nourishes her growing shark embryo internally and gives birth to a fully-functional live pup.

These shark species, like the hammerheads Sphyrnidae , maintain a placental link to the embryo, similar to humans. In aplacental viviparity, also called ovoviviparity, there is no placental link. The most common type of reproduction in sharks, ovoviviparity occurs when the egg hatches while still inside the mother. Sand tiger sharks Carcharias taurus will actually eat their siblings in the womb.

Female sand tiger sharks often mate with several different males, producing a litter of shark pups from a number of fathers. Researchers think that the larger sharks will consume their smaller siblings that are not as closely related to prevent competition.

Other shark species release an egg case, where the developing embryo gains nutrients from a yolk. This is called oviparity. Typically sharks that live on the seafloor, like the swellshark Cephaloscyllium ventriosum , are oviparous. They attach their egg case to a rock or other hard surface, or wedge it into a safe spot on a sandy bottom or rocky area.

Pacific white skates will attach their egg casings near the warmth of hydrothermal vents, potentially as a way to speed up the incubation process. The egg case of most sharks is a leathery transparent brown, with slits on either side that allow water to flow through to replenish oxygen in the sac.

The tiny shark moves around to help facilitate the water movement and, once the nutrients from the yolk sac are used up, the small shark makes it way out of the case to fend for itself. You can find a shark that eats just about anything: the whale shark, the biggest fish in the sea, eats only tiny plankton, while the bonnethead shark gets some of its nutrition from seagrass, a type of underwater plant.

Tiger sharks have even been found with license plates and nails in their stomachs. But most sharks are carnivorous and eat animals ranging from crustaceans like crabs to squid, fish and marine mammals like seals and sea lions. Potentially, we could rapidly build maps of species diversity and use them to create predictive models and identify the factors that influence diversity, while methods are being developed to improve the quantitative aspect of eDNA detection, also in other charismatic species.

All of it will be of great help to those who must devise plans to protect crucial habitats and ecosystems. Environmental DNA science is still rapidly developing. The databases that we use to match the unknown sequences retrieved from the sea must be enriched with new DNA references of many existing species — every multi-species eDNA study to date has detected large amounts of sequences that could not be matched against any reference.

A significant proportion of these belong to organisms that are yet to be described by scientists. For instance, the blacktip shark shared some identical sequences with the grey reef shark along the DNA stretch used in our study.

Nevertheless, all the initial indications suggest that this approach can get us a step closer to understanding and better managing the largest ecosystem on Earth. Judith swimming with a hammerhead in the Bahamas: sharks are hard to survey and track as the ocean is so vast. Sharks are often killed unintentionally by fishers using nets to catch other marine creatures but are also targeted for purposes such as making shark fin soup, which involves sharks having their fins hacked off before their helpless bodies are discarded back into the ocean.

The research highlights the patchwork quality of fisheries management around the world. Steep declines in shark and ray numbers in the Atlantic Ocean began to stabilize somewhat after amid conservation measures, while the rate of loss has also slowed in the Pacific Ocean. Many species of shark are migratory, meaning their protection requires the cooperation of different countries, while much of the harmful fishing occurs in the largely ungoverned high seas.