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Take one look at a great barracuda's
toothy grin and you'll understand why it has earned the nickname "Tiger of the Sea."

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With its sleek, torpedo-like body, dagger-like teeth, and ferocious appetite, the barracuda is built to hunt in the ocean. And that's exactly what it has been doing for the last 50 million years. Any diver who's seen a barracuda attack another fish can tell you that it happens faster than you can say "anchovy." One moment, a barracuda will be drifting lazily among the coral reefs. The next, it's rocketing toward a fish and snapping it up in its jaws.

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The Great Eating Machine
The great barracuda is an eating machine and it has the bulk to prove it. While some species of barracuda are less than a foot long, the great barracuda can measure up to 6 feet and weigh as much as 100 pounds. That's one big hungry fish!
So, is the barracuda a cold-blooded killer? You betcha! A barracuda is a predator because it needs to eat to survive. And it's cold-blooded because all fish are cold-blooded. They adapt to the temperature of the water surrounding them.

Barracudas Are Fishy!
If you think a barracuda is fishy looking, you're right. It's a fish. A barracuda shares several traits with most other fish, in addition to being cold-blooded. It is a vertebrate ? it has a spine. It has scales covering its body. It breathes using its gills rather than its lungs. It lays eggs rather than giving birth to live young. And, it swims by moving its fins (including its tail).

In order to move up and down quickly to track its prey and to move around the coral reefs, the barracuda uses itsswim bladder. A swim bladder is what keeps a fish from sinking to the bottom of the ocean, even though it's heavier than seawater. A barracuda can inflate or deflate this gas-filled chamber to lower its body or to rise.

Do Fish Breathe Like Us?
Yes and no. Yes, they need to breathe oxygen to survive. But, no, they don't breathe the same way we do. Fish don't have lungs at all. They have accordian-like organs called gills. In order to breathe, most fish gulp water in through their mouths and pump it over their gills. So when you see a barracuda opening wide, it's probably just getting a breath of "fresh air."
Barracuda are better adapted to hunting in the coral reefs than, say, a tuna because their bodies,
though long, are flexible enough to move through the twists and turns of a reef.

If it's such a great hunter, does this make the barracuda the most successful animal in the ocean? That's hard to measure. It hasn't been around for 50 million years just because it's lucky. But fish in general are an extremely successful class of animals. There are more than 25,000 different species of fish. This makes them, by far, the largest group of vertebrates. And there are millions, if not billions, of them. The oldest kinds of fish swam the seas more than 400 million years before the first dinosaur roamed the earth. So the next time you see a fish, show it a little respect, especially if it's a 'cuda.

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Pictures: Shane Paterson | Jackie Reid/NOAA | Shane Paterson |