Great White Shark
Chris Fallows/apexpredators.com
Great White Shark History
Great White Sharks, Carcharodon carcharias, are also known as white pointer or white shark is an exceptionally large lamniforme shark found in coastal surface waters in all major oceans. They reach lengths of about 20 feet and weigh over 4000 pounds. The Great White Shark is the world's largest known predatory fish. It is the only known surviving species of its genus, Carcharodon. They are also regarded as an apex predator with its only real threats from humans and occasionally orcas, which have been known to feed on great whites.
Great white sharks, like all other sharks, have an extra sense given by the Ampullae of Lorenzini, which enables them to detect the electromagnetic field emitted by the movement of living animals. Every time a living creature moves it generates an electrical field and great whites are so sensitive they can detect half a billionth of a volt. This is equivalent to detecting a flashlight battery from 1,000 miles away. To more successfully hunt fast moving and agile prey such as sea lions, the poikilothermic great white shark has developed adaptations that allow it to maintain a body temperature warmer than the surrounding water. One of these adaptations is a rete mirabile. This close web like structure of veins and arteries, located along each lateral side of the shark conserves heat by warming the cooler arterial blood with the venous blood that has been warmed by the working muscles. This keeps certain parts of the body running at temperatures up to 14° C above the surrounding water, while the heart and gills remain at sea-temperature. When conserving energy (a great white shark can go weeks between meals), the core body temperature can drop to match the surroundings. A great white shark's success in raising its core temperature is an example of gigantothermy. Therefore, the great white shark can be considered an endothermic poikilotherm, because its body temperature is not constant but is internally regulated
Ampullae of Lorenzini
Photo by R.M. Deeley, 2006
Authored by Anthony DeRose
28 March 2007