Sharks are fish that live in the ocean and are highly aggressive, mainly swimming inside the sea by their body, mostly reproducing by egg-laying.

Fish are characterized by living in the water, most of the fish body surface is covered with scales to reduce the resistance of the water, use gills to breathe, use fins to swim, rely on the tail and trunk of the left and right swing and the coordinated role of the fins to keep swimming forward, sharks have these characteristics, so they belong to the fish.

Sharks as early as 300 million years ago before the emergence of dinosaurs have existed on the earth, so far more than 500 million years, they are almost unchanged in nearly 100 million years. Sharks, in ancient times called sharks, sharks, sandfish, is the ocean behemoth, so called "wolf of the sea.

Expanded Information:

Exterior Characteristics

Sharks vary in size, from as small as 18 centimeters to as large as 18 centimeters in length. as small as 18 centimeters to as large as 18 meters. Whale sharks are the largest sharks in the sea, typically growing up to 36 feet in length. Despite its size, the whale shark has the smallest teeth of any shark. The smallest shark is the pygmy horn shark.

All sharks have a full complement of cartilage. A shark's skeleton is made of cartilage, not bone. Cartilage is lighter and more flexible than bone. All sharks belong to the class Carcharhiniformes, and all Carcharhiniformes have cartilage. But it is still harder.

Habitat:

Sharks mostly feed on marine animals such as fish. Sharks feed on injured marine mammals, fish, and carrion, culling the weaker members of the animal. Sharks also eat garbage and other debris thrown from boats.

In addition, some sharks prey on a variety of marine mammals, fish and animals such as turtles and crabs. Some sharks can go months without eating, and the great white shark is one of them. Great white sharks have been reported to eat only once every one or two months.

Baidu Encyclopedia - Sharks