Shark attack

A shark attack is an attack on a human by a shark. Every year, a number of people are attacked by sharks, although most survive. Despite the relative rarity of shark attacks, the fear of sharks is a common phenomenon, having been fueled by the occasional instances of attacks, such as the Jersey Shore shark attacks of 1916, and by sensationalized fiction and film, such as the Jaws series.

Statistics
In 2000, there were 79 shark attacks reported worldwide, 11 of them fatal. In 2005 and 2006 this number dropped to 61 and 62 respectively, while the number of fatalities dropped to only four per year. Of these attacks, the majority occurred in the United States (53 in 2000, 40 in 2005 and 38 in 2006). For the same period, the Global Shark Attack File records 69 unprovoked attacks of which five were fatal.

The Florida Museum of Natural History points out that these numbers should be compared with the much higher deaths from other, less feared causes; for example, several hundred people die annually from lightning strikes.

Species involved in incidents
Contrary to popular belief, only a few sharks are dangerous to humans. Out of more than 360 species, only four have been involved in a significant number of fatal unprovoked attacks on humans: the great white, tiger, oceanic whitetip and bull sharks. These sharks, being large, powerful predators may sometimes attack and kill people, but all of the above sharks, even the great white, have been filmed in open water, with no cage, time and time again without problems.

Current statistics fail to show that the oceanic whitetip shark is often involved in unprovoked attacks; however, this is misleading because it lives in the open sea and not near coasts. It has been involved in the aftermath of many air and sea incidents. Due to its abundance in the open oceans, it is often the first species on site when a disaster happens. These attacks do not appear in historical records, because quite often these victims fail to survive to tell the tale. Infamous examples of oceanic whitetip attacks include the sinking of the Nova Scotia, a steamship carrying 1000 that was sunk near South Africa by a German submarine in World War II. Only 192 people survived, with many deaths attributed to the oceanic whitetip shark. Another example was the torpedoing of the USS Indianapolis on 30 July 1945, giving a minimal figure of 60–80 killed by oceanic whitetips. Some survivors stated that tiger sharks were involved too.

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 reef, lemon, silky 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 divers and swimmers than the previous group. A few other shark species do attack people every year, producing wounds that can potentially kill, but this occurs either specifically because they have been provoked, or through mistaken identity due to water conditions or the like.

Why do sharks sometimes attack?
There are many theories about why sharks sometimes attack people. Some attacking species, such as the Great white shark, may be confusing a human for a seal or other prey animal; this would be typical in the case of an attack against a surfer. The shape of a surfer lying on a board closely resembles a seal from beneath the surface. Also, sharks have sensory organs on their nose to pick up electrical signals, such as those generated by muscles when moving. Often the shark that attacks a human will make only one bite and then go away. This behaviour has many possible explanations, one being that humans don't taste good (or at least, as good), or are lacking the necessary fat, and another being that sharks normally make one swift attack, and then retreat and wait for the victim to die, or exhaust itself, before it comes back to feed. This protects the shark from injury from a wounded and aggressive target; however, it also allows humans time to get out of the water and survive. Another theory is that the electrical receptors, which pick up movement, do not pick up the same signals from a wounded human as they would a wounded seal, and so they are more cautious. In fact, it has recently been shown that surfers do not give off the same electrical signals as seals, or it is thought there would be far more attacks.