The great white shark, also known as the white shark, white pointer, or simply great white, is a species of large mackerel shark which can be found in the coastal surface waters of all the major oceans. They have slate-gray upper bodies to blend in with the rocky coastal sea floor, but they get their name from their white underbellies. They’re streamlined, torpedo-shaped swimmers with powerful tails that can propel them through the water at speeds of up to 15 miles per hour. They can even leave the water completely, breaching like whales when attacking prey from underneath.
Hunting and diet
Highly adapted predators, their mouths are lined with up to 300 serrated, triangular teeth arranged in several rows, and they have an exceptional sense of smell to detect prey. They even have organs that can sense the tiny electromagnetic fields generated by animals. Their prey includes other sharks, crustaceans, molluscs, and sea birds. Larger whtie sharks will also prey on sea lions, seals, and small toothed whales like orcas. The species has even been seen feeding on dead whales.
Of the 100-plus annual shark attacks worldwide, a third to a half are attributed to great white sharks. Most of these, however, are not fatal. Research finds that great whites, which are naturally curious, often “sample bite” then release their human target. It’s not a terribly comforting distinction, but it does indicate that humans are not actually on the great white’s menu. Fatal attacks, experts say, are typically cases of mistaken identity: Swimmers and surfers can look a lot like their favorite prey—seals—when seen from below.
Population and conservation
There is no reliable population data for the great white shark, but scientists agree that their number are decreasing precipitously. Overfishing and getting accidentally caught in fishing nets are their two biggest threats. The species is classified as vulnerable—one step away from endangered—by the International Union for the Conservation of Nature.
Importance of Great White Sharks
As apex predators, sharks play an important role in the ecosystem by maintaining the species below them in the food chain and serving as an indicator for ocean health. They help remove the weak and the sick as well as keeping the balance with competitors helping to ensure species diversity.
As predators, they shift their prey’s spatial habitat, which alters the feeding strategy and diets of other species. Through the spatial controls and abundance, sharks indirectly maintain the seagrass and corals reef habitats. The loss of sharks has led to the decline in coral reefs, seagrass beds and the loss of commercial fisheries.
By taking sharks out of the coral reef ecosystem, the larger predatory fish, such as groupers, increase in abundance and feed on the herbivores. With less herbivores, macroalgae expands and coral can no longer compete, shifting the ecosystem to one of algae dominance, affecting the survival of the reef system. Oceana released a report in July 2008, “Predators as Prey: Why Healthy Oceans Need Sharks”, illustrating our need to protect sharks.
Sharks Help Clean Ocean
Sharks are sometimes called the garbage cans of the ocean. This title is most frequently applied to tiger sharks, which have been known to eat various items of trash including cans, bottles, tires, coal, rags, nails and even a chicken coop.
By feeding on dead matter that collects on the seafloor, scavengers such as deep-sea sharks, hagfish and starfish help to move carbon through the ocean. In addition, research has found that large marine animals such as whales and sharks sequester comparatively large amounts of carbon in their bodies.