Great White Sharks Feeding, Hunting and Prey | Sea Life, Islands and Oceania

GREAT WHITE SHARKS FEEDING

Great white attacking a fake seal

Great white sharks feed primarily on seals, sea lions, dolphins, elephant seals, turtles, sea birds and large fish, including salmon and other sharks. They have been seen feasting on dead whales and will feed on creature they can catch, including crabs, snails, squid, small fish and occasionally humans. Their preferred prey are young seals or elephant seals, which have a high-calorie layer of thick blubber, don't put much of fight and weigh about 200 pounds. They and can be killed and consumed by a single shark in less than a half hour. The large mouth, powerful jaws and large, triangular, serrated teeth of the great white shark are designed for ripping into the flesh of its prey.

Young great white sharks typically feed on smaller species such as squid and stingrays, as well as other small sharks. As these fish get older their eating habits change. The diet of adults consists primarily of seals, sea lions, dolphins, and whale carcasses. One of the most frequent prey animals of great white sharks are elephant seals. Sometimes they feed on turtles and various sea birds. [Source: Dana Chewning and Matt Hall, Animal Diversity Web (ADW)]

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. R. Aidan Martin and Anne Martin wrote in Natural History magazine, “ The white shark's diet includes bony fish, crabs, rays, sea birds, other sharks, snails, squid, and turtles, but marine mammals may be its favorite meal. 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. [Source: R. Aidan Martin, Anne Martin, Natural History magazine, October 2006]

Websites and Resources: Shark Foundation shark.swiss ; International Shark Attack Files, Florida Museum of Natural History, University of Florida floridamuseum.ufl.edu/shark-attacks ; Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Fishbase fishbase.se ; Encyclopedia of Life eol.org ; Smithsonian Oceans Portal ocean.si.edu/ocean-life-ecosystems ; Woods Hole Oceanographic Institute whoi.edu ; Cousteau Society cousteau.org ; Monterey Bay Aquarium montereybayaquarium.org ; MarineBio marinebio.org/oceans/creatures

Great White Shark Hunting

Great white upper teeth

Great white sharks may use different hunting and attacking strategies depending on the size of their prey. The most common attack method used by great white sharks involves the shark positioning itself directly below its prey and then swimming vertically into an attack. These sharks collide into their prey and then bite them. Prey often die from blood loss, decapitation or severance of vital appendages such as fins. [Source: Dana Chewning and Matt Hall, Animal Diversity Web (ADW)]

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 then appears and finishes it off.

Douglas Herdson at the National Marine Aquarium in Plymouth told The Guardian that great whites typically feed on seals and, unlike other sharks, they rely on sight rather than scent or sound to find their prey. They lurk at the bottom and look up for a seal-like silhouette. When great whites strike, they rapidly swim upwards and, just before reaching the surface, release an ink-like liquid into their eyes to prevent the sunlight from dazzling them. "They normally take one bite and then back off. Then, when they think the prey is either dead or weakened, they come back in to feed." [Source: Ian Sample, The Guardian, December 17, 2004]

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. They sometimes swim with their teeth bared, apparently to warn off competitors for food or let other great whites know they are approaching too close to shark’s personal space. Tagged sharks in False Bay in South Africa, hunt seals when they are present at Seal Island but abandon the island when summer approaches — and the seals leave the island — and patrol close to shore, just beyond the breakers.

Great White Shark Hunting and Foraging Theory

Great white lower teeth

R. Aidan Martin and Anne Martin wrote in Natural History magazine, “ How does a white shark decide what to eat? 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. [Source: R. Aidan Martin, Anne Martin, Natural History magazine, October 2006]

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.

Great White Sharks: Picky Eaters?

R. Aidan Martin and Anne Martin wrote in Natural History magazine, “ Far from being the indiscriminate killers the movies have portrayed, white sharks are quite selective in targeting their prey. 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. [Source: R. Aidan Martin, Anne Martin, Natural History magazine, October 2006]

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.

Great White Sharks Attack of Seals

20120518-Megalodon_tooth_with_great_white_sharks_teeth.jpg
Megalodon tooth (black) with great white sharks teeth
Seals; sea lions and elephant seals are favorite great white shark prey. But sharks often attack them cautiously, apparently fearing injury from a seal’s claws or teeth. Frequently they bite, then back off and allow the prey to bleed to death.

Peter Klimey of the University of California has videotaped more than 100 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 400 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." Klimley told Discover, "The sharks appear to attack from ambush. 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...is one that provides them with the best camouflage."

One of the best places to see great white sharks is offshore from Seal Island in False Bay, near Cape Town in South Africa. 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, 60,000 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. Shark expert Alison Kick told Smithsonian magazine, “They want to go to sea to feed but they’re afraid of the white sharks.”

Great white sharks begin attacking the seals minutes after the first ones leave Seal Island to go out to sea. Paul Raffaele wrote in Smithsonian magazine, “The attacks begin...A 3,000-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. "I've seen them swim all around them and nip the shark in the tail." [Source: Joe Mozingo, Los Angeles Times, August 22, 2011]

Great White Shark Hunting Seals at Seal Island, South Africa

Describing an attack on a seal pup, Adrian and Anne Martin wrote in Natural History magazine, “Suddenly a a ton of white shark launched from the water like a Polaris missile, the little seal clamped between his teeth...the shark clears the surface by an astonishing six feet. 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. An enormous blush stains the water and an oily, coppery smell of the wounded seal pricks our nostrils. The seal carcass float to the surface while gull gulls and other seabirds compete for its entrails.”

The Martins wrote: “The white shark relies on stealth and ambush when hunting seals. It stalks its prey from the obscurity of the depths, then attacks in a rush from below. Most attacks at Seal Island take place within two hours of sunrise, when the light is low. Then, the silhouette of a seal against the water's surface is much easier to see from below than is the dark back of the shark against the watery gloom from above. The shark thus maximizes its visual advantage over its prey. The numbers confirm it: at dawn, white sharks at Seal Island enjoy a 55 percent predatory success rate. As the sun rises higher in the sky, light penetrates farther down into the water, and by late morning their success rate falls to about 40 percent. After that the sharks cease hunting actively, though some of them return to the hunt near sunset. [Source: R. Aidan Martin, Anne Martin, Natural History magazine, October 2006]

But Cape fur seals are hardly helpless victims. They are big, powerful predators in their own right, and take defensive advantage of their large canine teeth and strong claws. They also exhibit a remarkable range of antipredator tactics. Swimming quickly in small groups to or from the Launch Pad minimizes their time in that high-risk zone, and they remain in the relative safety of the open sea for extended periods. When they detect a white shark, seals often do a headstand, vigilantly scanning underwater with their rear flippers in the air. They also watch one another closely for signs of alarm. Alone, in pairs, or in threes, Cape fur seals occasionally even follow a white shark, swirling around it as if to let the would-be predator know its cover has been blown.

To avoid a shark attack, seals may leap in a zigzag pattern or even ride the pressure wave along a shark's flank, safely away from its lethal jaws. If an attacking shark does not kill or incapacitate a seal in the initial strike, superior agility now favors the seal. The longer an attack continues, the less likely it will end in the shark's favor. Cape fur seals never give up without a fight. Even when grasped between a white shark's teeth, a Cape fur seal bites and claws its attacker. One has to admire their pluck against such a formidable predator.

Great White Sharks Strategy Killing Seals

A study by Neil Hammerschlag of the University of Miami published in the Zoology Society of London’s Journal of Zoology found that great white sharks at Seal Island don’t just go after their victims randomly but rather use methods similar to those used by serial killers. “There’s some strategy going on,” Hammerschlag, told AP. “It’s more than sharks lurking at the water waiting to eat them.” [Source: Seth Borenstein. AP, June 2009]

Hammerschalg observed 340 great white shark attacks of seals at Seal Island. He observed that the sharks had a clear mode of operation. They tended to stalk their victims from a distance of 90 meters, close enough to see their prey and far enough away so their prey couldn’t see them. They attacked when the light was low and sought victims that were young and alone. They liked to attack when no other sharks were present. Most of all the liked to surprise their victims, sneaking up from below, unseen.

Hammerschalg’s team analyzed the great white’s action using “geographic profiling,” a method used in criminology that looks for patterns in where criminals strike. They surmised that the sharks learned from previous kills by the fact that larger, older sharks had more success making kills than younger, inexperienced ones.

Great White Shark Bites and Eating Methods

Describing the results of experiments with great white sharks and fake plywood seal, Burney L. Beoeuf of the University of California at Santa Cruz told Discover, "More often than not, they tended to initially mouth prey candidates delicately rather than just munch down. They're very particular about what they bite into. I have an intuitive sense that they have a soft mouth, like bird dogs. They get a tremendous amount of information from their mouths."

Klimey theorizes that great whites can tell the consistency and fat content of objects when they bite into them. If it is a seal they clamp on and go for the kill. If it is not they back off and save their energy for a more productive attack.

Because seals have sharp claws and can badly injure a shark during an attack, a great white usually bites once and then waits for their prey to die. The last thing a shark wants to do is eat or fight with an animal that is still struggling wildley.

Once their prey is dead, great whites go about eating it in a leisurely way, not a frenzy. Tom Cunneff wrote in Sports Illustrated, "Every minute or so the surface ripples. The shark takes a bite of the elephant seal, dives and circles back. Bite by bite over the next half hour the predator eats the 200-pound pinniped. The scene is peaceful and rhythmic."

Great whites often release animals after biting into them and more like to do this if they bite into a relatively low fat creature like a sea otter or human than a high-fat seal or sea lion. Klimley told Smithsonian magazine, “It may be a textural discrimination [of fat], more than what we could call taste...We once took a seal and stripped the fat off it and put it all the water. The shark ate the fat but not the rest of the body. They are actually very discriminating predators.”

Great White Shark Group Hunting Behavior

While tracking multiple great whites, researchers found that some great white sharks form groups and stay together for more than an hour when patrolling areas around Guadalupe Island off Baja California. The reason they do may this, scientists deduce, to kill larger prey by working together. [Source: Joshua Hawkins, BGR, March 26, 2022]

Joshua Hawkins wrote in BGR: The group of researchers, including Florida International University marine scientist Yannis Papastamatiou, say they wanted to learn more about the white sharks that gather around Guadalupe Island each year. The waters around the island are teeming with tuna and seals, which makes it a living buffet for the sharks.To study them, the team created a “super social tag”. This tag allowed them to track the sharks. They were also able to capture video footage of them using an array of different sensors. These sensors showed them depth, direction, and even how quickly the sharks turned when swimming. The secret weapon of the tracker, though, was the sensor that detected nearby sharks with tags issued during previous studies. The new tags were designed to collect data for up to five days. Then, once the five days were completed, the tags would pop off the dorsal fin and float to the surface of the water for collecting. Altogether the team tagged six great white sharks, three males and three females, throughout a four-year period.

Following a study into the data collected by the “super social tags”, researchers discovered that some sharks would gather in groups to patrol around the island. Many of the interactions were short, never lasting more than seven minutes or so. However, some sharks chose to stay together and hunt for more than an hour.

The tracker also gave the researchers a good look at the shark’s different hunting habits. For example, some great whites preferred to hunt in deeper water, while others stayed in shallow areas. Even more, some chose to hunt at night, while others hunted during the day. The footage of the sharks hunting also showed multiple attempts where the prey managed to get away from the sharks. This isn’t abnormal, as predators do not always manage to catch their prey when hunting. However, Papastamatiou says it could help prove why great white sharks congregate together at times . Papastamatiou says they aren’t necessarily doing it to work together. Instead, it may just be a way of sharing information, should one shark manage to kill some large prey while the others were unsuccessful.

Image Sources: Wikimedia Commons; YouTube, Animal Diversity Web, NOAA

Text Sources: Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Wikipedia, National Geographic, Live Science, BBC, Smithsonian, New York Times, Washington Post, Los Angeles Times, The New Yorker, Reuters, Associated Press, Lonely Planet Guides and various books and other publications.

Last Updated March 2023