The great white shark (Carcharodon carcharias) is a species of cartilaginous fish found in coastal and pelagic waters. The great white shark is the largest predatory fish capable of eating marine mammals that weight several hundred pounds. The only two fishes that grow larger than Great Whites are the whale shark and the basking shark, both filter feeders that eat plankton.
Reaching lengths of up to 20 feet (6 m) and weights of several tons, the great white’s body is perfectly adapted to a life of predation.
Great white sharks are known to be highly migratory, with individuals making long migrations every year. In the eastern Pacific Ocean, great whites regularly migrate between Mexico and Hawaii. In other ocean basins, individuals may migrate even longer distances. Like in many highly migratory species, the very largest individuals are female.
Great whites mate via internal fertilization and give live birth to a small number of large young (over three feet/one meter). Though they give live birth, great whites do not connect with their young through a placenta. Instead, during the gestation period, the mother provides her young with unfertilized eggs that they actively eat for nourishment. After they are born, young great whites are already natural predators, and they eat coastal fishes. As they grow, their preferred prey also gets larger, and the largest, mature individuals prefer to eat marine mammals, like seals and sea lions. Great whites are known to take very deep dives, probably to feed on slow-moving fishes and squids in the cold waters of the deep sea.
Though almost all fish are cold-blooded, great whites have a specialized blood vessel structure – called a countercurrent exchanger – that allows them to maintain a body temperature that is higher than the surrounding water. This adaptation provides them with a major advantage when hunting in cold water by allowing them to move more quickly and intelligently. It is also particularly advantageous when hunting warm-blooded marine mammals that might otherwise have too much energy for great whites to successfully capture them.
While great whites are one of the few species known to have bitten and killed people, these events are extremely rare. According to Oceana, when a great white does bite a person, it only takes one exploratory bite and quickly realizes that the person is not its preferred prey. Unfortunately due to their very large size, even an exploratory bite can be fatal or extremely traumatic. People, on the other hand, capture too many great whites, through targeted fisheries or accidental catch in other fisheries, and scientists generally consider great whites to be vulnerable to extinction.