How do great white sharks behave

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. All rights reserved. Common Name: Great White Shark. Scientific Name: Carcharodon carcharias.

Type: Fish. Diet: Carnivore. Group Name: School, shoal. Size: 15 feet to more than 20 feet. Weight: 2. Size relative to a bus:. Least Concern Extinct. Current Population Trend: Unknown. This photo was submitted to Your Shot, our photo community on Instagram. Though almost all fishes 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. Typically, 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. Great whites often return year after year to the same hunting grounds. It is believed that they have a feast or famine diet.

They may gobble up an entire seal one day and then go a month or more without eating anything. Many of them are big, powerful animals in their own right, but predators with the means to catch them hit caloric pay dirt when they sink their teeth into the mammals' thick layer of blubber.

Pound for pound, fat has more than twice as many calories as protein. By one estimate, a fifteen-foot white shark that consumes sixty-five pounds of whale blubber can go a month and a half without feeding again. In fact, a white shark can store as much as 10 percent of its body mass in a lobe of its stomach, enabling it to gorge when the opportunity arises such as when it encounters a whale carcass and live off its hoard for extended periods.

Usually, though, white sharks eat more moderately. Great whites like to stalk their prey from behind and below, and then attack, taking a massive bite and then waiting for their victim to bleed to death. They often sneak up on sea lions, seals and elephant seals from below and attack from behind.

They usually take a powerful first bite underwater and the first indication on the surface is a large slick of blood. Minutes later, the victim appears on the surface with a large chunk missing.

The shark thne appears and finishes it off. Great whites have been observed shooting vertically upwards from a depth of 10 meters and knocking their prey right out of the water to stun it. Off South Africa great whites have been seen leaping five meters out of the water with a seal in their mouth. The impact stuns the prey and often leaves it with a chunk taken out it. The sharks then attack again or wait for their victims to bleed to death. Great white sharks hunting for seals in waters off South Africa swim around three meters off the bottom in water that is 10 to 35 meters feet deep and wait up to three weeks before making a lightning quick strike from below on a seal at the surface.

Tagged sharks in False Bay in South Africa, hunt seals when they are present at Seal Island but abandon the island when summer approachesand the seals leave the islandand patrol close to shore, just beyond the breakers.

Megalodon tooth with great white sharks teeth R. A model known as optimal foraging theory offers a mathematical explanation of how predators weigh the calorie content of food against the energetic cost of searching for it and handling it. According to the theory, predators employ one of two basic strategies: they seek to maximize either energy or numbers.

Energy maximizers selectively eat only high-calorie prey. Their search costs are high, but so is the energy payoff per meal. Numbers maximizers, by contrast, eat whatever kind of prey is most abundant, regardless of its energy content, thereby keeping per-meal search costs low. Based on optimal foraging theory, A. Peter Klimley, a marine biologist at the University of California, Davis, has proposed an intriguing theory about the feeding behavior of the white shark.

According to Klimley's theory, white sharks are energy maximizers, so they reject low-fat foods. That neatly explains why they often feed on seals and sea lions but rarely on penguins and sea otters, which are notably less fatty.

As we mentioned earlier, however, white sharks eat maW other kinds of prey. Although those prey may be low-cal, compared with sea mammals, they may also be easier to find and catch, and thus sometimes energetically more attractive. It seems likely that white sharks follow both strategies, depending on which is the more profitable in a given circumstance. Of all marine mammals, newly weaned seals and sea lions may offer the best energy bargain for white sharks. They have a thick layer of blubber, limited diving and fighting skills, and a naivete about the dangers lurking below.

Furthermore, they weigh in at about sixty pounds, a good meal by anyone's standards. Their seasonal presence at certain offshore islands--Seal Island, the Farallon Islands off San Francisco, and the Neptune Islands off South Australia--draws white sharks from far and wide. Each winter, white sharks drop by Seal Island for between a few hours and a few weeks, to feast on young-of-the-year Cape fur seals.

White sharks that visit either Seal Island or the Farallon Islands come back year after year, making those islands the marine equivalent of truck stops.

But on what basis does a shark select one individual from a group of superficially similar animals? No one knows for sure. Many investigators think predators that rely on single-species prey groups, such as schools of fish or pods of dolphins, have developed a keen sense for subtle individual differences that indicate vulnerability. An individual that lags behind, turns a little slower, or ventures just a bit farther from the group may catch the predator's eye.

Such cues may be at work when a white shark picks a young, vulnerable Cape fur seal out of the larger seal population at Seal Island. The location and timing of predatory attacks are also far from indiscriminate. At high tide on the Farallon Islands, for instance, there is heavy competition for space where northern elephant seals can haul themselves onto the rocks, and the competition forces many low-ranking juvenile seals into the water.

Klimley--along with Peter Pyle and Scot D. Anderson, both wildlife biologists then at the Point Reyes Bird Observatory in California--has shown that at the Farallons, most white-shark attacks take place during high tide, near where the mammals enter and exit the water.

Similarly, at Seal Island, Cape fur seals leave for their foraging expeditions from a small rocky outcrop nicknamed the Launch Pad. Coordinated groups of between five and fifteen seals usually leave together, but they scatter while at sea and return alone or in small groups of two or three. White sharks attack almost any seal at Seal Island--juvenile or adult, male or female--but they particularly target lone, incoming, young-of-the-year seals close to the Launch Pad.

The incoming seal pups have fewer compatriots with which to share predator-spotting duties than they do in the larger outgoing groups.

Furthermore, they're full and tired from foraging at sea, making them less likely to detect a stalking white shark. Peter Klimey of the University of California has videotaped more than attacks by great white sharks of elephant seals, sea lions and harbor seals at the Farallon Island, a group of rock islets west of San Francisco.

Recalling an attack of an pound elephant seal, Klimley told Time magazine, "It was stunning. The shark ambushed the seal, then came back several times to take three or four bites out of it. I had never seen anything like it The white shark is a skillful and stealthy predator that eats with both ritual and purpose.

From a seal's perspective, the dark grey of the sharks' backs could blend almost perfectly with a rocky bottom, and heavy surf could further serve to obscure them. The area of the best attacks Large sharks are routinely seen here leaping from the water with seals in their mouths.

The waters around Seal Island are a favorite feeding area for great white sharks. On the flat, rocky island, a third of a kilometer long, 60, Cape fur seals gather. The seals are often attacked in the morning as they leave the island for their feeding ground 60 kilometers out in the bay. The attacks generally occur in the hour after dawn, because, scientists think, after that time, the seals can see the sharks approaching them from underwater and can escape.

In the morning the seals are often jittery. Great white sharks begin attacking the seals minutes after the first ones leave Seal Island to go out to sea. A 3,pound great white explodes out of the water. In mid air the shark lunges at a seal and flips back into the water with a mighty splash, Moments later another shark breaches and bites a seal, We speed to the spot, in time to see a pool of blood.

Scores of gulls hover above, screeching in excitement, they swoop down to gobble up any leftovers During an hour and a half, we witness ten great white sharks hurtling out of the water to grab seals.

As the rising sun brightens the sky, the attacks stop. Joe Mozingo of Los Angeles Times wrote: "Even the great white's dynamic with seals is not what you might suspect in the open water, Winram said. Sharks attack injured seals or sneak up on them as they enter the water from the beach. But once the seals can see them in the open water, they are too agile for the sharks to catch. It hangs, silhouetted in the chill air for what seems like an impossibly long time before it falls back into the sea, splashing thunderous spray Now mortally wounded and lying on its side at the surface, the seal raises its head and weakly wags its left foreflipper The shark, an eleven-and-a-half-foot male.

Circles back unhurriedly and seizes the hapless seal pup. He carries it underwater, shaking his head violently from side to side, an action that maximizes the cutting efficiency of his saw-edged teeth. Either shark or both, will twist its head towards the other and then continue on their original course. The information here is collected from our team who offer a range of cage diving and share diving adventures.

Click here for the list of the best places to scuba dive in Africa. White sharks use the South African coastline differently throughout the year. They spend the summer August to March very close inshore and during the winter March to August they congregate around seal colonies such as those in False Bay, Mossel Bay and Dyer Island.

The exact reasons behind this transition between inshore and offshore migratory behaviour are not entirely clear. There are two possible reasons for these migrations:. For more information visit www. White Shark gaping. Below are a few common behaviours witnessed by White Shark Projects — a shark diving and shark research operator in Hermanus, which launches its excursion boats from Gansbaai in South Africa: Gaping Obviously, sharks do not have arms, legs, hands or feet.