Dinosaur World, Kentucky – Source: Photo by Peter Rivera from Flickr
Sharks have existed since hundreds of millions of years ago, where dinosaurs were still present then. Common species of sharks such as the Great White Shark, Whale Shark as well as Hammerhead Shark might sound pretty familiar to you, however, you might not be aware that there are actually more than 400 different species of sharks living in the world.
Sharks are one of the fastest fish in the sea. Preys are able to be detected by sharks from a great distance due to their extraordinarily sharp sense of smell, hearing and sight. Sharks are able to see clearly even when they are deep down in the sea where it is dimly lighted. As such, these make sharks very efficient predators.
Sharks are carnivorous and feed on fishes which includes other sharks as well as larger marine animals such as seals. A small number of species feed on tiny plankton or krill. Though humans have an impression that sharks are ruthless predators, they are also highly chanced to be killed by humans, which we will talk about in the Threatening Factors.
With the presence of different threatening factors, the number of sharks have decreased by a huge amount of 90% in the last 20 to 30 years. This pushes sharks towards extinction which can bring along undesired consequences to the environment which we will talk about in the Importance.
