Great white shark (Carcharodon carcharias)
Best known from the movie Jaws, the great white is a large, heavy-bodied shark, about 20 feet long, with large bladelike teeth. Widely the most-feared of sharks, great white attacks are rare, and most scientists agree that its reputation is undeserved. Many scientists believe it is endangered due to sport fishing and shrinking food supplies.
Great white sharks are an enigma, as scientists are still trying to unravel the mysterious lifestyle of these denizens of the deep. They are solitary creatures roaming the ocean in constant search of food. Scientists are still unsure how to tell the age of a great white shark or how long they live, how often and where they breed, and how quickly they grow.
It is widely held among shark experts that the great whites take a long time to reach the fearsome proportions of record and that over fishing of these incredible creatures has led to a rapid decline in their numbers. No one knows how long it would take for the world's great white shark numbers to rebound if we were to completely halt fishing of this species. We are now beginning to realize the important role they play in their ecosystem, eliminating the weak and the sick from their environment and keeping seal and sea lion numbers in check. Lack of great white sharks to control the sea lion population may be one of the contributing factors to the declining salmon populations along the coast of California and Oregon.
What scientists have been able to study in great whites is their predatory and feeding behavior. In the Farallon Islands, off the coast of California, scientists are videotaping and documenting attacks on pinnipeds(seals and sea lions - the sharks' favorite prey) to understand how these awesome killing machines operate. By studying shark attack behavior, scientists hope to understand and predict how and when a great white will attack. People who "use" the ocean can use this information to protect themselves from being attacked by a great white shark.
Expert Killing Machines
Great white sharks have a number of adaptations (behaviors and anatomical features) that make them such efficient killers:
For sensing - specialized sensory organs called ampullae of Lorenzinilocated in the shark's snout, which can detect electrical currents of as little as .005 millivolts that are generated by every living creature in the water
Extremely acute and sensitive sense of smell, allowing the great white to detect the most miniscule amounts of blood in the water up to 5km away - blood means injured victim = less effort required for the meal (Efficiency!)
For stalking- the coloring of the great white makes for excellent camouflage in the ocean - dark above, and light below makes it difficult to be detected while swimming on the bottom (great whites strike from below)
For striking- a large, powerful body and specially designed tail that provides for enormous bursts of energy for striking with such tremendous strength that the first bite is frequently a death blow
Several rows of razor sharp teeththat are continually replaced to ensure an entire jaw of efficient, lacerating implements
Scientists who study the Great White Shark have found that when attacking their prey, the strategy of the great white is usually to strike from below in one powerful blow (some human shark attack victims have likened the experience to being hit by a car), inflicting a lethal bite to head or trunk of its victim. The shark then swims away a short distance to let its victim bleed to death so that it will not have to struggle with its meal. This brief respite after the initial chomping is what allows many human victims (but not all) to escape being eaten alive by the great white predator.