字幕表 動画を再生する 英語字幕をプリント It's the size of a whale but it's actually the world's largest fish! I'm Jonathan Bird and this is shark academy! Well as shark experts of course you all know that sharks are fish. The whale shark is not only the world's largest shark…it's the world's largest fish, and it's called a whale shark because it's the size of a whale. It's not a whale. It's not related to whales. Whales breath air. They are mammals. Sharks are fish. So the whale shark is a fish the size of a whale. The whale shark is really big! We're talking: they reach fifty feet long. That's the length of two school buses end to end. So this is a very very large fish. How does it get so big? Well, it eats a lot. But you might be surprised what it eats. Whale sharks survive almost exclusively on plankton and small fish. A whale shark feeds by swimming through the water with its mouth wide open, scooping in vast quantities of water. The water goes into the back of the throat and it goes back out through the gills. But on the gills are little combs called gill rakers and they're filters. What happens is the plankton gets stuck in the filters when the water goes through and then every once in a while the shark closes his mouth and swallows all the plankton down. So the whale shark is completely harmless to people, even if a person went into its mouth, it wouldn't be able to swallow you because it only has a throat about this big. The throat is designed for swallowing small things, little fish, plankton, not people. Completely harmless to people. The only way a whale shark could hurt you is if someone dropped one on you, or maybe if it hit you with its tail. But I don't know anybody stupid enough to get hit with the tail of a whale shark. One of the most interesting characteristics of the whale shark is its skin pattern. It has sort of a polka-dotted stripey pattern that almost looks like dominoes. In fact in some countries they're called the Domino shark. Nobody's quite sure what this coloration pattern is for, the best guess is that it helps with that dappling of light near the surface, it almost helps create a sort of camouflage on their back. But why would they need camouflage, are they sneaking up on the plankton? Nobody really knows. So since the whale shark is so humongous, you would expect that it would have a pretty large babies. Actually it doesn't. The pups are born only about a foot long. Because they're so small the female can give birth to over three hundred pups at a time. A female whale shark can't produce babies until she's thirty years old, so it takes a long time for all those pups to grow up. So even though the whale shark has a lot of pups, they're still vulnerable to over-fishing. If you want to learn more about whale sharks, check out the link below, my adventure filming whale sharks in Mexico! If you're on Facebook or Twitter check out the links right here, become a fan, we'd love to hear from you. And if you want to tell us something about sharks or make a request, leave a comment down below. Of course if you haven't subscribed yet, dude what are you doing? Hit the subscribe button! Until next time, I'm Jonathan Bird and this is Shark Academy!