Day 40 - How much do you know about sharks?

It is well known that sharks are carnivorous fish that live in the ocean. Most of them can live up to 30 years; however, some sharks can live up to 100 years. Unlike other fish, sharks do not have swim bladders, so if they stop swimming, they sink right away. Sharks are the perfect example of sink or swim. When it comes to reproduction, some of them lay eggs, and others give birth to live young. Sharks do not have bones, and their skeletons are made of cartilages which help them to bend easily. And, surprisingly, there are 360 different kinds of sharks in the world of all shapes and sizes. First, great white sharks can be 20 to 39 feet long and weigh two tons or even more. They are fast swimmers. They have many sharp teeth and eat fish, seals, dolphins, and other sharks. They are known as good hunters because they can see better in the dark than cats. And they can sense things moving and smell blood in the water. They have good hearing, too. That's why not a single prey can get by them.
Second, whale sharks are the biggest fish in the ocean. They grow up to 60 feet long and weigh 40 tons. They are called whale sharks because they are as big as whales. They eat plankton and use their gill rakers to catch them. They are known as people friendly sharks because they are gentle and do not hurt people.
Third, mega mouth sharks open their mouths wide when they swim and eat plankton. Hammerhead sharks have heads that look like hammers. Lantern sharks, which are the smallest sharks, glow in the ocean. Spiny dogfish can live up to 100 years. Wobbegong sharks, which look like carpet, usually stay on the bottom of the ocean. Third, even though sharks rarely attack people, it is necessary to know some practical tips to avoid a shark attack. People should not wear jewelry in the water because it will shine like fish scales which are very attractive to sharks. Next, it is better to swim as a group and stay near the shore. If a person is bleeding, she or he must not be in the water because sharks can smell and taste blood. Swimming at night, at dawn, and at dusk is not recommended because sharks are usually active at those times. Splashing a lot in the water is also very dangerous because the movement of water will give signals to sharks. Finally, many people think sharks are dangerous and harmful. However, some sharks do not even have teeth, and not all sharks are human eaters. The fact is that they usually eat sick and dying fish which helps the balance of the ocean and ecosystem. Therefore, sharks are not just scary sea monsters but important helpers in the ocean. This is the end of my speech. Thank you for listening.

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