The great white sharks have undoubtedly inspired many Hollywood film makers, which in turn, through the means of their movies, have most of the times conveyed and emphasized a basic instinctive fear to the audience for this great predators of the oceans. However, convinced that in nature there are no good or bad players, but they are all part of same interconnected world, I decided to take a closer look and learn more about this species, and one safe way to do it is by means of a cage diving, with a professional crew formed of marine wildlife biologists, in one of the places with greatest density of white sharks in the world, Gansbaai, Indian Ocean coast, South Africa! The trick they said was just to lure the shark with bate, and never feed them, to spoil their wild behavior, and to associate boats with food! A list with more destinations in South Africa for such an adventure can be found on internet, here is one of them.
Apart from the completely safe but unique adventure, what I learned was that scientists have relatively recently started to learn more about the great white sharks, for example about their migration habits, whereas it has been always thought this was a coastal animal. Currently the status of great white sharks is that they are vulnerable, threaten by fishing and human activity, as the only natural predators are exceptionally the killer whales (the orca). A February 2010 study by Barbara Block of Stanford University estimated the world population of great white sharks to be lower than 3,500 individuals, making the species more vulnerable to extinction than the tiger, whose population is in the same range. According to another study from 2014 by George H. Burgess, Florida Museum of Natural History, University of Florida, there are about 2000 great white sharks near the California coast, which is 10 times higher than the previous estimate of 219 by Barbara Block.
The females, larger than males (typical for species which dont fight for reproductive rights or territory), can reach up to 6 m and 3 tonnes in weight, and can live up to 70 years. Humans are not the preferred prey of the great white shark, but, nevertheless, the great white is responsible for the largest number of reported and identified fatal unprovoked shark attacks on humans (especially on surfers being taken for a seal…they have also been known to eat objects that they are unable to digest, due to same error). Great white sharks, like all other sharks, have an extra sense given by the special organ called “ampullae of Lorenzini” which enables them to detect the electromagnetic field emitted by the movement of living animals. Great whites are so sensitive they can detect variations of half a billionth of a volt. At close range, this allows the shark to locate even immobile animals by detecting their heartbeat. Most fish have a less-developed but similar sense using their body’s lateral line.
Great white sharks are oviparous, which means eggs develop and hatch in the uterus and continue to develop until birth. The great white has an 11-month gestation period. Sharks taken during the long interval between birth and sexual maturity (at around 15 years of age) never reproduce, making population recovery and growth difficult.