Sharks are predator fish, dangerous and aggressive inhabitants of the ocean, the oldest known animals. So it is commonly believed, and millions of people believe in this knowledge of these unique creatures from Hollywood thriller thrillers. We will understand what we know about these amazing creatures that appeared much earlier than all civilizations of the world and perfectly adapted in modern life.
All scientific and encyclopedic publications claim that sharks are cartilaginous fishes, that is, they have absolutely no bone tissues in their bodies, which distinguishes them sharply from their modern counterparts in their habitat. Together with the absence of gill covers and features of the structure of scales, the cartilaginous Ostyak indicates the primitiveness of the species’s organization, or rather its ancient origin: it is known that 400 million years ago these fish already sailed in the world’s oceans.
Despite this, sharks are one of the most advanced species of carnivorous ocean fish. For a long time adapting to the constantly changing environment, they perfectly adapted and now perfectly get along with modern bony fish and marine mammals, not yielding to them in speed, agility, or hunting skills.
The list of sharks includes more than 400 species, polar different: from the shallowest deep-sea, barely growing to 17-20 cm, to the giant – a whale shark, a huge 20-meter multitone specimen.