Sharks 101 | National Geographic
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Sharks 101 | National Geographic

November 17, 2019

(ominous music) – [Narrator] They glide through the water with unmistakable grace, remnants of an ancient past, they dive and they rise from the ocean’s murky depths to it’s sun-kissed shallows, rousing fear and awe like no other creature in the sea. The world’s biggest
living fish is a shark. Of the estimated 34,000 species of fish, the largest are whale sharks. These gentle giants usually
grow to about 40 feet long and weigh an estimated 15 tons. Their mouths alone can
span four feet wide. The gigantic whale shark however, pales in comparison to the largest fish that ever existed, the megalodon. Dating to over 20 million years ago, it’s thought that the prehistoric shark could of reached 80 feet long, weighing up to around 70 tons. Unlike whale sharks, the
megalodon was carnivorous, and consumed any creature that fit into it’s nearly 10 foot wide mouth. Throughout their lives
some species of shark can shed over 30,000 teeth. Unlike humans who are born with a set number of teeth in their jaws, sharks have a seemingly limitless supply. They can grow, lose, and
replace their teeth as needed. Furthermore, most sharks have multiple rows of teeth in their jaws. The jaws of a great white shark, the largest predatory fish in the sea, can contain up to seven rows that hold up to 300
teeth at any one point. Most sharks, as they hunt their prey, end up losing their teeth individually. However, the cookiecutter shark loses and replaces the teeth in
it’s lower jaw all at once. Sharks are built for speed. The fastest known shark, the mako shark, can reach speeds of up
to 46 miles per hour. This speed is largely due to their body’s hydrodynamic design. Many sharks have torpedo shaped heads that allow them to cut through the water with little resistance. Plus, shark skin is covered
with flat, v-shaped scales, called dermal denticles. The denticles help water
flow smoothly over the skin, which reduces friction and helps sharks swim quickly and quietly. Sharks also have skeletons made of cartilage instead of bone. Cartilage is a much
lighter material than bone so sharks have less weight to carry. Sharks may lay eggs, or bear live young. Egg laying sharks only
lay a few large eggs. They may come in various forms, such as sacks called mermaid
purses or corkscrews. These eggs act as external wombs in which shark embryos
complete their development. However, most sharks
give birth to live young. Called pups, the young of
most live bearing species gestate for around one year. Some even begin practicing
their predation skills while in the womb. Before they are born, the
sand tiger shark pups compete with their siblings. In fact, the strongest pup
in each of the two wombs devours its weaker brothers and sister. Some sharks are at risk of extinction. Every year an estimated 100 million sharks are killed worldwide, in large part for the shark fin trade. The sharks are caught
and their dorsal fins are removed and sold at a hefty price, primarily in Asia. In traditional Chinese culture, serving and eating shark fin is a sign of status and wealth. Because of the high demand
and value of shark fins, some shark populations have plummeted by up to 70% causing a ripple effect in ecosystems and endangering
at least 74 shark species. However, measures are being
taken to protect sharks with a number of countries and
jurisdictions cracking down on unsustainable shark fishing. In China, shark fin soup
is no longer allowed to be served at government banquets. A move hailed by shark conservationists. Through continued international
conservation efforts, the loss of sharks may be curbed, allowing the creatures in
all their power and grace to survive for many generations to come.

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  1. The world's biggest living fish is a shark. What intrigues you the most about these amazing creatures?

  2. If I were a president in any any country (comment down below what country you want) I would hang all fishermen who hunt sharks and also other endangered species. Except for snakes in the government( i will eat em all)

  3. 100 millions sharks are killed each year😢. I only eat sharksfinsoup when I have no choice, but I definitely wouldn’t order it.

  4. Yes and they're being hunted to extinction by both accident and on purpose, mostly for their fins. We have to help save them not endanger them.

  5. I hated seeing Somalia, Mogadishu even mentioned bc of what happened in 93’ with the US Army special forces.

  6. We have a million sustainable foods yet humans still need to fish until extinction. Good on you! Like Agent Smith said in the Matrix…humans are a virus.

  7. Megalodon is 4 meters bigger than I expected who knows they might be 24 meters megalodons 😐

  8. 20 million years ago.
    Sad. They. Still. Teach. This.
    Read the bible.
    Evolution is wrong.
    The earth is not that old.
    Wrong information.
    Do your research before believing this.
    Watch kent hovind.

  9. The fact that people cut off sharks fins off is so sad, I’m glad their being protected. I maybe scared of sharks but I would never in my life would grab a shark out of the water and cut off its fin! That’s just cruel.

  10. Sharks are more afraid of us than we are of them the same goes for snakes who try to scare us of cause they think we are gonna eat them

  11. 0:50 I agree that megalodon was likely the largest predatory shark to ever exist, but wasn't the largest "fish" in general Leedsichthys, from the Jurassic period? Where did that 80 foot estimate for Megalodon come from? I'm just curious.

  12. no matter how deadly animals are. humans always finds a way to kill them and sell for money. at the end, money is the thing that governs this entire world.

  13. Sharks are terrifying, but they’re so cool! Whenever I’m at the beach, I’m always kind of scared that there are sharks. (Where I live, there are seals at beaches, which also means sharks sometimes 😂)

  14. Great footage, lots of info, and a succinct summary of conservation threats all packed into a short video. Outstanding.

  15. 1:02, Im going to stop you there, no scientist ever conclude that megalodon was 80ft long and the few that do are mistaken

  16. Hahahah yeah so how many times we gotta tell ya Meg's were thought to be 60ft not 80ft not 100ft but 60ft Sixty!

  17. These shark fin consumers are detrimental to the eco system! Scientists are realising how seriously important sharks are in the ocean. And humans are supposedly an intelligent species? 🙄🙄🙏🙏 pray for these animals.

  18. shark fishing in Indonesia, but I never eat one before 🙁 the demand must be from the wealthy one. please save Indonesia shark population

  19. People that never go swimming: sharks are so beautiful and harmless its so rare for a shark attack to happen

    People that go swimming often: sharks are the scariest things out there they are ugly and killers

  20. In Northern part of China we ppl wanna clearify that—we don't have this tradition and we are even not close to the seeeeaaaaaaaaaaaaaaaaaaa

  21. I learned that there were various kinds of sharks and there were some sharks that did not pose a threat to humans. But I'm stii afraid of sharks😰😰

  22. Sharks are predators of the sea. I can't forget that excitement when I watch movies or videos about sharks. I remember going to the aquarium last year to see the ironclad shark. It wasn't a scary-looking shark I knew and I thought it was rather cute. I want to see sharks even in the real sea.

  23. Sharks are predators of the sea. I can't forget that excitement when I watch movies or videos about sharks. I remember going to the aquarium last year to see the ironclad shark. It wasn't a scary-looking shark I knew and I thought it was rather cute. I want to see sharks even in the real sea.

  24. The shark was cool. Also its teeth were sharper than I thought. The whale shark in the video was very naive, unlike the shark we knew, and it was amazing to come up to us first. It was amazing that there was such an animal among sharks. So I was curious about the animals that came first to humans.

  25. Narrator: Sharks have limitless teeth
    Me: I heard there was this boy who has 200 teeth and kept on doing surgery to lose those 200 teeth

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