Introduction to sharks

Sharks are a kind of fish with streamlined body. They are not sea mammals.

Size:
Sharks can be really small. The small dwarf lanternshark is of only 17 centimetres (6.7 in) in length, while whale shark, the largest fish, can be 12 metres (39 ft 4 in) long. The image above shows a whale shark, the great white shark, and a human for scale.

Habitat:
There are about 440 species of sharks and they can be found in all seas. Some sharks like the bull shark and the river shark can also live both in freshwater and seawater.

Food:
Most sharks are carnivorous. They feed on fishes and squid. They can swallow small fishes or take big bites of huge fishes. Whale shark, basking shark, and megamouth shark use filter feeding to take in plankton and small fishes.

Evolution:
Sharks existed on earth from over 450-420 million years ago, though they looks very different from the sharks we see now. At about 100 million years ago, sharks evolved into the modern sharks.

Shark attack:
Do shark attack human? Yes, they do. But only a few sharks are dangerous to humans. The great white shark, oceanic whitetip shark, tiger shark, and bull sharks are reported to attack and kill human.

Right click on the picture and select to print out from your computer.



The Megalodon_scale1.png was created by Misslelauncherexpert, Matt Martyniuk. Free license under the terms of the GNU Free Documentation License.