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Jul 25, 2019 · Find out about the world's biggest and fastest sharks, how sharks reproduce, and how some species are at risk of extinction. Subscribe: http://bit.ly/NatGeoSubscribe #NationalGeographic #Sharks #...
- 5 min
- 8.4M
- National Geographic
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the Batoidea ( rays and kin).
Join Jessi and Squeaks to learn some super shark fa... Sharks are fascinating creatures with cool teeth, awesome scales, and there are over 450 kinds of sharks!
- 4 min
- 4.5M
- SciShow Kids
- Anatomy
- Behavior
- Attacks
- Threats
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Like rays and skates, sharks fall into a subclass of fish called elasmobranchii. Species in this subclass have skeletons made from cartilage, not bone, and have five to seven gill slits on each side of their heads (most other fish have only one gill slit on each side), which they use to filter oxygen from the water. Whale sharks, the largest fish s...
Sharks are found in deep and shallow waters throughout the world’s oceans, with some migrating vast distances to breed and feed. Some species are solitary, while others hang out in groups to varying degrees. Lemon sharks, for example, have been foundto congregate in groups to socialize. Scientists are still trying to figure out how long sharks live...
People aren’t on a shark’s menu. Even though shark attacks have increased at a steady ratesince 1900—a result of better recording of attacks and a rising human population—they are still exceedingly rare: A beachgoer has only a one in 11.5 million chance of being bitten. Sharks bite people out of curiosity, to defend themselves from a perceived thre...
Sharks may not be a significant threat to us, but we are to them. Humans are responsible for drastic declines in shark populations. Overfishing is the biggest threat. An estimated 100 million sharks are killed each year, mostly to supply demand for an expensive Chinese dish called shark fin soup. Some fisheries allow the catch of whole sharks, like...
Learn about the world's most ancient and diverse fish, from their skeletons and teeth to their diets and migrations. Find out how sharks are threatened by overfishing, climate change, and human activities.
Jul 1, 2024 · Sharks differ from other elasmobranchs, however, and resemble ordinary fishes, in the fusiform shape of their body and in the location of their gill clefts on each side of the head. Though there are exceptions, sharks typically have a tough skin that is dull gray in colour and is roughened by toothlike scales.
- Jeffrey Carrier
Introduction. There are more than 500 species of sharks swimming in the world’s ocean. Yet when most people think of these cartilaginous fish, a single image comes to mind: a large, sharp-toothed and scary beast. That generalization does sharks a huge disservice, as they have far more variety than that.
SRI conducts and sponsors rigorous, peer-reviewed field research about sharks and uses science-based information to educate and advocate for shark conservation policies and protections by the world’s governing bodies, including CITES.
