Are All Sharks Dangerous?
No – only a few kinds of sharks attack people. In fact, some sharks are frightened by people. There are 480 kinds of sharks. About 03 types of sharks are dangerous and responsible for two-digit numbers of fatal unprovoked attacks on humans: the great white, tiger and bull; however, the oceanic whitetip has probably killed many more castaways, not recorded in the statistics.
These sharks will eat anything that comes their way, including people. Surprisingly, the biggest shark (the whale shark) is not dangerous to people. It eats only plants and small sea creatures. One reason sharks are such terrific predators is that their teeth are always new and razor sharp. They lose old, worn-out teeth and replace them with new, sharp ones throughout their lives.
It is possible that the sharks are able to sense the presence of unnatural elements on or about the divers, such as polyurethane diving suits and air tanks, which may lead them to accept temporary outsiders as more of a curiosity than prey. Un-costumed humans, however, such as those surfboarding, light snorkeling, or swimming, present a much greater area of exposed skin surface to sharks.
In addition, the presence of even small traces of blood, recent minor abrasions, cuts, scrapes, or bruises, may convince sharks to attack a human in their environment. Sharks seek out prey through electroreception, sensing the electric fields that are generated by all animals due to the activity of their nerves and muscles.
Most of the oceanic whitetip shark’s attacks have not been recorded, unlike the other three species mentioned above. Famed oceanographic researcher Jacques Cousteau described the oceanic whitetip as “the most dangerous of all sharks”.
Modern-day statistics show the oceanic whitetip shark as being seldom involved in unprovoked attacks. However, there have been a number of attacks involving this species, particularly during World War I and World War II. The oceanic whitetip lives in the open sea and rarely shows up near coasts, where most recorded incidents occur.
During the world wars, many ship and aircraft disasters happened in the open ocean, and because of its former abundance, the oceanic whitetip was often the first species on site when such a disaster happened.
Infamous examples of oceanic whitetip attacks include the Nova Scotia, a British steamship carrying 1,000 people that was sunk on November 18, 1942, near South Africa by a German submarine in World War II. Only 192 people survived, with many deaths attributed to the oceanic whitetip shark. The same species is probably responsible for many of the 60–80 or more shark casualties following the torpedoing of the USS Indianapolis on July 30, 1945.
Black December refers to at least nine shark attacks on humans causing six deaths that occurred along the coast of KwaZulu-Natal Province, South Africa, from December 18, 1957, to April 5, 1958.
In addition to the four species responsible for a significant number of fatal attacks on humans, a number of other species have attacked humans without being provoked, and have on extremely rare occasions been responsible for a human death. This group includes the shortfin mako, hammerhead, Galapagos, gray reef, blacktip, lemon, silky shark and blue sharks.
These sharks are also large, powerful predators which can be provoked simply by being in the water at the wrong time and place, but they are normally considered less dangerous to humans than the previous group.
On the evening of 16 March 2009, a new addition was made to the list of sharks known to have attacked human beings. In a painful but not directly life-threatening incident, a long-distance swimmer crossing the Alenuihaha Channel between the islands of Hawai’i and Maui was attacked by a cookiecutter shark. The two bites, delivered about 15 seconds apart, were not immediately life-threatening.
A great white shark is believed to be responsible for an attack on a swimmer at Muriwai Beach in Auckland, New Zealand in February 2013. It was the first confirmed shark attack fatality in the country since 1976.