Yachting Art Magazine

When we think of sharks, the Great White Shark or even its extinct ancestor, the Megalodon, immediately spring to mind; they are the terror of the oceans in the collective imagination. However, these two super-predators are far from being the ideal candidates to represent sharks, which are divided into 529 species (not counting rays, which are classified as sharks) and only five of which are currently considered dangerous to humans: the Great White Shark, the Tiger Shark, the Bull Shark, the Mako Shark and the Longfin Shark.

So what is the profile of a typical shark? Which shark can most accurately represent all its fellow creatures?

The majority of shark species are grouped in the order Carcharhiniformes, which includes more than 270 species such as hammerhead sharks, tiger sharks and leopard sharks, for example. This order also includes the dogfish, a family of small sharks comprising more than 150 species (making it the largest family of sharks known to date), such as the great dogfish, the pygmy dogfish and the pyjama shark.

In comparison, the order Lamniformes, to which the Great White Shark belongs, includes only 16 species, some of which, such as the Megamouth Shark, are among the rarest ever observed.

Furthermore, not all sharks have the same diet, even though they are all carnivorous. The whale shark, the basking shark and the sailfish shark are planktonophagous sharks (feeding on plankton), while many other sharks feed on small fish or crustaceans that they hunt, sometimes in packs.

One of the sharks considered dangerous to humans, the tiger shark is perhaps the most opportunistic of all sharks, hunting just about anything it can and swallowing its prey indiscriminately. It feeds on other smaller sharks, sea snakes, birds and even whales on occasion. And because it makes little distinction between the things it hunts and eats, it has also been observed attacking sea turtles and swallowing objects from human industry such as cans, plastic bags and even number plates.

This is one of the reasons why it is dangerous to humans. In addition to its aggressiveness, it attacks without distinguishing between its other prey, whereas the Great White Shark, which is also dangerous but whose reputation is exacerbated by the media, is not systematically aggressive or hostile. Its attacks, probably motivated by confusion with its usual prey such as seals and pinnipeds, are generally considered accidental, which calls into question its reputation for being dangerous.

Sharks also live in all the seas and oceans of the world, with the exception of Antarctica, and even in some large rivers and lakes, at depths that vary greatly depending on the species.

Sharks can be found in the abyss, such as the Noronhai shark, on the seabed, such as the Greenland shark, whose life expectancy of at least 300 years is the longest known among vertebrates; or in rivers and lakes, such as the Ganges shark or the bullhead shark, which are euryhaline fish (able to live in both saltwater and freshwater).

And while most known shark species live in warm, tropical and subtropical seas, such as the Horned Sleeping Sharks or the Hammerhead Sharks, which can form schools of up to a hundred individuals, many sharks are migratory, such as the Salmon Shark, which lives mainly in the North Pacific but can migrate to subtropical areas and travel more than 18,000 kilometres in less than two years, meaning that its habitat can vary enormously.

This incredible variety among sharks can undoubtedly be explained by their long evolution, as the first sharks appeared in the Devonian period (the Age of Fish) around 420 million years ago. By comparison, the first hominids only appeared around 20 million years ago.

This long evolution may explain the wide variety of species, sizes and habits among sharks, most of which only adopted their modern form during the Cretaceous period (100 million years ago). Sharks range in size from just nine centimetres long for the dwarf lantern shark to over twenty metres for the whale shark.

It is therefore very difficult to describe a typical shark, because sharks form a superorder of fish that includes as many species as there are sizes, habits and habitats.

Today, many shark species are threatened with extinction due to the deterioration of their natural habitat and fishing, and their unjustified bad reputation does not help their conservation.

Many endangered species are not even protected. However, organisations and associations are working to raise public awareness. One example is Ailerons, a French association created in May 2006 that works to improve knowledge and protect rays and sharks in the Mediterranean.