Introducing Sharks

Sharks are very interesting sea creatures and this is probably the reason behind why i am researching on them. When the word "shark" is mentioned, many people would immediately describe its nature as dangerous. Some may even associate it with shark fin soup. Thus, i feel that the all of us should be more educated about sharks as their populations are actually declining.

What are sharks?

Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago, even before the time of the dinosaurs. Since that time, they have already diversified into 440 species. They are found in all seas and are common down to depths of 2000 metres. They generally do not live in freshwater and respire with the use of five to seven gill slits. Sharks have a covering of dermal denticles that protect their skin from damage and parasites and improve fluid dynamics so the shark can move faster. They also have several sets of replaceable teeth. Well-known species such as the great white and the hammerhead are apex predators at the top of the underwater food chain. Their extraordinary skills as predators fascinate and frighten humans, even as their survival is under serious threat from fishing and other human activities.