Great white sharks have been portrayed as cold, calculated killers with a thirst for human blood. This depiction couldn’t be far from the truth.
Great white sharks aren’t evil murderers – they’re just large predators obeying their instincts. They may attack humans from time to time, but they rarely eat them, and once you know what they do eat, you’ll soon understand why.
What do Great White Sharks Eat?
Great white sharks are opportunistic carnivores that eat a wide range of different foods.
As they mature, great whites develop a preference for marine mammals, such as seals, dolphins, and sea lions, but they don’t restrict themselves to these species.
A study of great white sharks in South African waters found that they eat crustaceans, cephalopods, fish, other sharks, and even whales.
Great white sharks rarely attack and kill whales, although it does happen on occasion, but regularly feed off their decomposing remains.
As juveniles, great whites have a more limited diet, perhaps because of their size or because they have yet to perfect their hunting skills.
They tend to restrict themselves to fish, crustaceans, rays, and squid. Marine mammals only become a part of their diet as they mature.
Although they have a diverse diet, great white sharks are a little more discerning than tiger sharks, which eat all sorts of garbage and discarded objects.
In one study, however, a rubber gumboot appeared inside the stomach of one great white, proving that they don’t always select their food according to taste!
The Great White Shark Diet
If a great white shark had a menu, it would contain the following dishes (in order of preference):
- Seals, including grey seals, northern elephant seals, harbor seals, earless seals, and brown fur seals
- Dolphins of various species, including harbor, dusky, and bottlenose
- Whales, including beaked whales and humpbacks
- Fish, including tuna and mackerel
- Seabirds, including gulls, penguins, and cormorants
Great white sharks do not need a knife and fork as they have up to 3,000 teeth available to do the work for them. Despite all those teeth, they don’t chew their prey either.
Instead, they shake their heads, tearing off chunks of meat that they then swallow whole.
In addition, to live prey, great white sharks are quite content to scavenge on decomposing carcasses, especially those of whales. Last year, eight great white sharks abandoned their solitary hunting missions to share a meal of decomposing humpback whales.
Researchers have noticed that, when scavenging on a carcass, great white sharks target the blubber “leaving behind the muscle tissue.” This led them to believe that the sharks would ignore the carcass of a tuna because it lacked the fat they were targeting.
This theory proved incorrect when a study of great whites near Guadalupe Island found they showed more interest in the carcass of a yellowfin tuna than that of a sea lion.
They concluded that the great whites in this area may have developed a taste for fish after being fed by “recreational dive and sportfishing fleets” or because of the seasonal abundance of fish in the area.
How Much do Great White Sharks Eat?
Only a couple of studies have explored the quantity of food a great white shark needs to consume to stay alive.
The first one, published in 1982, concluded that “a 943kg white shark could survive on 30 kg of marine mammal blubber for approximately 1.5 months.”
The second study, published over 30 years later, disputed this, suggesting that the original researchers had “picked a shark that probably wasn’t working very hard at the time.”
Great white sharks are in constant motion and use massive amounts of energy as they engage in high-speed pursuits and leap from the water to secure their prey.
This level of energy requires fuel, so it would make sense that a “hard-working” great white would need to consume large amounts of food to keep it moving.
The study, conducted at a cape fur seal colony off the coast of the Neptune Islands in South Australia, estimated that the great white expends around 22.1 MJ of energy per day.
To sustain this level of activity, a 943 kg shark would need to eat 30 kg of blubber every 11.6 days rather than every 1.5 months.
To achieve this, it would need to successfully hunt at least one fish per day or one seal cub every three days.
How do Great White Sharks Hunt for Food?
Great white sharks have highly developed senses that help them accurately locate their prey. Although their eyesight isn’t particularly good at distinguishing humans on surfboards from seals, they’re still “highly visual creatures” that rely on “rely on motion and shadows” to detect their prey.
Great whites don’t hunt by sight alone, however, and have such a good sense of smell that they can detect a single drop of blood within the equivalent of an Olympic-sized swimming pool.
Not only do great whites have the largest olfactory bulb of any shark, but they also have a network of electroreceptors that can detect the tiniest of electrical currents.
This ability enables the shark to pinpoint the location of its prey, even in poor visibility.
Great white sharks use different hunting strategies according to the prey. When hunting seals, they attack almost vertically, usually starting their ascent at depths of around 90 ft.
By the time the shark reaches its target, it’s traveling at approximately 34kph and often leaps from the water as it makes its kill.
After this spectacular display of power and aggression, the great white will often leave its injured prey to weaken before returning to finish it off.
“Stealth and ambush are key elements in the white shark’s predatory strategy,” which could explain why they are generally solitary hunters that are most active when the light levels are low.
Great whites may be solitary, but they are often close enough to one another that, should one make a successful kill, the others can quickly capitalize on it.
What Animals Compete for Food with Great White Sharks?
In the past, scientists believe great white sharks may have competed with Megalodons for food, but these days some of the fiercest competition comes from others of the same species.
Great white sharks act aggressively towards one another in the presence of food, sometimes even attacking and biting their opponent, as this video shows. Such footage has led some to believe that great whites are cannibalistic, actively preying on others of the same species.
Older, larger great whites also appear to prevent smaller sharks from accessing “the most profitable hunting locations.”
That suggests that Megalodons should have come out on top in a fight for resources, but that isn’t the case. Some scientists even believe the great white may have played a role in the Megalodon’s demise by making “a big enough dent in the shared food supply.”
Aside from competing with one another, great white sharks have another rival that not only endangers their food supply but threatens their lives as well.
Great white sharks are so afraid of orcas that, should they arrive in the great white’s favorite hunting spot, the shark will vacate the area for months, if not years.
The diet of orcas is very similar to that of great whites, putting the two species in direct competition. Orcas appear to have the upper hand, however and have forced the great whites to abandon some of their favorite feeding grounds off the coast of South Africa.
Has a Great White ever Eaten a Human?
According to the International Shark Attack File, great white sharks have been responsible for over 350 attacks on humans, many of which proved fatal. In most instances, however, the shark doesn’t actually eat the human.
The great white’s first bite is an exploratory one, but is often fatal.
Only once the great white has tasted its prey does it decide whether or not it’s worth eating.
As it’s seeking blubbery prey like seals, a human isn’t particularly appealing to most great whites, although there have been a few instances where the shark has appeared to completely consume its human prey.
Did Megalodons Eat Great Whites?
Great whites, hammerheads, and tiger sharks all prey on other sharks. As the Megalodon was large enough to swallow a great white whole, it probably did predate them.
Great white sharks are opportunistic hunters and scavengers with a diverse diet. As juveniles, they mainly prey on rays, fish, and other sharks, but as they mature they move onto marine mammals, and seals in particular.
Although aggressive, great white sharks don’t actively target humans but may mistake them for other prey species, resulting in an attack.
There’s nothing evil or sinister about the great white shark – it’s just a formidable predator following its instincts and fighting for survival in an increasingly competitive ocean.
Nicky is a British adventurer and animal lover who spends her time exploring the natural world and writing about her experiences. Whether on horseback, underwater, running, hiking or just standing with a fishing rod in hand, she embraces everything her adopted home of South Africa has to offer.