- Sharks have evolved about 500 different species.
Sharks are the subject of many movies.
The largest shark is the whale shark.
Sharks are highly streamlined and suitable for swimming.
Sharks are distributed throughout the world.
Sharks can survive in the sea 2000 meters deep.
Sharks are the top predators in the water food chain.
The number of sharks affected by human activities has been greatly reduced.
- The earliest known sharks date back to more than 420 million years ago.
Sharks are found in all seas and are common to depths of 2,000 metres.
- Sharks are generally do not live in freshwater although there are a few known exceptions, such as the bull shark and the river shark.
The oldest generally accepted shark scales are from about 420 million years ago, in the Silurian period.
The first sharks looked very different from modern sharks.
- The bull shark and the river shark can be found in both seawater and freshwater.