Great white shark lifespan

Species of large lamniform shark

"White shark" redirects here. For the novel, see White Shark (novel). For the golfer, see Greg Norman.

The great white shark (Carcharodon carcharias), 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. It is the only known surviving species of its genusCarcharodon. The great white shark is notable for its size, with the largest preserved female specimen measuring 5.83 m (19.1 ft) in length and around 2,000 kg (4,400 lb) in weight at maturity.^[3] However, most are smaller; males measure 3.4 to 4.0 m (11 to 13 ft), and females measure 4.6 to 4.9 m (15 to 16 ft) on average.^[4][5] According to a 2014 study, the lifespan of great white sharks is estimated to be as long as 70 years or more, well above previous estimates,^[6] making it one of the longest lived cartilaginous fishes currently known.^[7] According to the same study, male great white sharks take 26 years to reach sexual maturity, while the females take 33 years to be ready to produce offspring.^[8] Great white sharks can swim at speeds of 25 km/h (16 mph)^[9] for short bursts and to depths of 1,200 m (3,900 ft).^[10]

The great white shark is arguably the world's largest-known extant macropredatory fish, and is one of the primary predators of marine mammals, such as pinnipeds and dolphins. The great white shark is also known to prey upon a variety of other animals, including fish, other sharks, and seabirds. It has only one recorded natural predator, the orca.^[11]

The species faces numerous ecological challenges which has resulted in international protection. The International Union for Conservation of Nature lists the great white shark as a vulnerable species,^[1] and it is included in Appendix II of CITES.^[12] It is also protected by several national governments, such as Australia (as of 2018).^[13] Due to their need to travel long distances for seasonal migration and extremely demanding diet, it is not logistically feasible to keep great white sharks in captivity; because of this, while attempts have been made to do so in the past, there are no known aquariums in the world believed to house a live specimen.^[14]

The great white shark is depicted in popular culture as a ferocious man-eater, largely as a result of the novel Jaws by Peter Benchley and its subsequent film adaptation by Steven Spielberg. Humans are not a preferred prey,^[15] but nevertheless it is responsible for the largest number of reported and identified fatal unprovoked shark attacks on humans.^[16] However, attacks are rare, typically occurring fewer than 10 times per year globally.^[17][18]

Taxonomy

The great white is the sole recognized extant species in the genus Carcharodon, and is one of five extant species belonging to the familyLamnidae.^[19] Other members of this family include the mako sharks, porbeagle, and salmon shark. The family belongs to the Lamniformes, the order of mackerel sharks.^[20]

Etymology and naming history

The English name 'white shark' and its Australian variant 'white pointer'^[21] is thought to have come from the shark's stark white underside, a characteristic feature most noticeable in beached sharks lying upside down with their bellies exposed.^[22] Colloquial use favours the name 'great white shark', with 'great' perhaps stressing the size and prowess of the species,^[23] and "white shark" having historically been used to describe the much smaller oceanic white-tipped shark, later referred to for a time as the "lesser white shark". Most scientists prefer 'white shark', as the name "lesser white shark" is no longer used,^[23] while some use 'white shark' to refer to all members of the Lamnidae.^[20]

The scientific genus name Carcharodon literally means "jagged tooth", a reference to the large serrations that appear in the shark's teeth. It is a portmanteau of two Ancient Greek words: the prefix carchar- is derived from κάρχαρος (kárkharos), which means "jagged" or "sharp". The suffix -odon is a romanization of ὀδών (odṓn), a which translates to "tooth". The specific namecarcharias is a Latinization of καρχαρίας (karkharías), the Ancient Greek word for shark.^[19] The great white shark was one of the species originally described by Carl Linnaeus in his 1758 10th edition of Systema Naturae, in which it was identified as an amphibian and assigned the scientific name Squalus carcharias, Squalus being the genus that he placed all sharks in.^[24] By the 1810s, it was recognized that the shark should be placed in a new genus, but it was not until 1838 when Sir Andrew Smith coined the name Carcharodon as the new genus.^[25]

There have been a few attempts to describe and classify the great white before Linnaeus. One of its earliest mentions in literature as a distinct type of animal appears in Pierre Belon's 1553 book De aquatilibus duo, cum eiconibus ad vivam ipsorum effigiem quoad ejus fieri potuit, ad amplissimum cardinalem Castilioneum. In it, he illustrated and described the shark under the name Canis carcharias based on the jagged nature of its teeth and its alleged similarities with dogs.^[a] Another name used for the great white around this time was Lamia, first coined by Guillaume Rondelet in his 1554 book Libri de Piscibus Marinis, who also identified it as the fish that swallowed the prophet Jonah in biblical texts.^[26] Linnaeus recognized both names as previous classifications.^[24]

Fossil ancestry

Molecular clock studies published between 1988 and 2002 determined the closest living relative of the great white to be the mako sharks of the genus Isurus, which diverged some time between 60 and 43 million years ago.^[28][29] Tracing this evolutionary relationship through fossil evidence, however, remains subject to further paleontological study.^[29]

The original hypothesis of the great white shark's origin held that it is a descendant of a lineage of mega-toothed sharks, and is closely related to the prehistoric megalodon.^[29][30] These sharks were considerably larger in size, with megalodon attaining an estimated length of up to 14.2–20.3 m (47–67 ft).^[31][32][33] Similarities between the teeth of great white and mega-toothed sharks, such as large triangular shapes, serrated blades, and the presence of dental bands, led the primary evidence of a close evolutionary relationship. As a result, scientists classified the ancient forms under the genus Carcharodon. Although weaknesses in the hypothesis existed, such as uncertainty over exactly which species evolved into the modern great white and multiple gaps in the fossil record, palaeontologists were able to chart the hypothetical lineage back to a 60-million-year-old shark known as Cretalamna as the common ancestor of all sharks within the Lamnidae.^[28][30]

However, it is now understood that the great white shark holds closer ties to the mako sharks and is descended from a separate lineage as a chronospecies unrelated to the mega-toothed sharks.^[29] This was proven with the discovery of a transitional species that connected the great white to an unserrated shark known as Carcharodon hastalis.^[34][35] This transitional species, which was named Carcharodon hubbelli in 2012, demonstrated a mosaic of evolutionary transitions between the great white and C. hastalis, namely the gradual appearance of serrations,^[34] in a span of between 8 and 5 million years ago.^[36] The progression of C. hubbelli characterized shifting diets and niches; by 6.5 million years ago, the serrations were developed enough for C. hubbelli to handle marine mammals.^[34] Although both the great white and C. hastalis were known worldwide,^[29]C. hubbelli is primarily found in California, Peru, Chile, and surrounding coastal deposits,^[37] indicating that the great white had Pacific origins.^[34]C. hastalis continued to thrive alongside the great white until its last appearance around one million years ago^[38] and is believed to have possibly sired a number of additional species, including Carcharodon subserratus^[29][34] and Carcharodon plicatilis.^[29]

However, Yun argued that the tooth fossil remains of C. hastalis and Great White Shark "have been documented from the same deposits, hence the former cannot be a chronospecific ancestor of the latter." He also criticized that the C. hastalis "morphotype has never been tested through phylogenetic analyses," and denoted that as of 2021, the argument that the modern Carcharodon lineage with narrow, serrated teeth evolved from C. hastalis with a broad, unserrated teeth is uncertain.^[39]

Tracing beyond C. hastalis, another prevailing hypothesis proposes that the great white and mako lineages shared a common ancestor in a primitive mako-like species.^[40] The identity of this ancestor is still debated, but a potential species includes Isurolamna inflata, which lived between 65 and 55 million years ago. It is hypothesized that the great white and mako lineages split with the rise of two separate descendants, the one representing the great white shark lineage being Macrorhizodus praecursor.^[40][41]

Distribution and habitat

Great white sharks live in almost all coastal and offshore waters which have water temperature between 12 and 24 °C (54 and 75 °F), with greater concentrations in the United States (Northeast and California), South Africa, Japan, Oceania, Chile, and the Mediterranean including the Sea of Marmara and Bosphorus.^[42][43] One of the densest-known populations is found around Dyer Island, South Africa.^[44] Juvenile great white sharks inhabit a more narrow band of temperatures, between 14 and 24 °C (57 and 75 °F), in shallow coastal nurseries.^[45] Increased observation of young sharks in areas they were not previously common, such as Monterey Bay on the Central California coast, suggest climate change may be reducing the range of juvenile great white sharks and shifting it toward the poles.^[46]

The great white is an epipelagic fish, observed mostly in the presence of rich game, such as fur seals (Arctocephalus ssp.), sea lions, cetaceans, other sharks, and large bony fish species. In the open ocean, it has been recorded at depths as great as 1,200 m (3,900 ft).^[10] These findings challenge the traditional notion that the great white is a coastal species.^[10]

According to a recent study, California great whites have migrated to an area between Baja California Peninsula and Hawaii known as the White Shark Café to spend at least 100 days before migrating back to Baja. On the journey out, they swim slowly and dive down to around 900 m (3,000 ft). After they arrive, they change behaviour and do short dives to about 300 m (980 ft) for up to ten minutes. Another white shark that was tagged off the South African coast swam to the southern coast of Australia and back within the year. A similar study tracked a different great white shark from South Africa swimming to Australia's northwestern coast and back, a journey of 20,000 km (12,000 mi; 11,000 nmi) in under nine months.^[47] These observations argue against traditional theories that white sharks are coastal territorial predators, and open up the possibility of interaction between shark populations that were previously thought to have been discrete. The reasons for their migration and what they do at their destination is still unknown. Possibilities include seasonal feeding or mating.^[48]

In the Northwest Atlantic, the white shark populations off the New England coast were nearly eradicated due to over-fishing.^[49] In recent years, the populations have grown greatly,^[50] largely due to the increase in seal populations on Cape Cod, Massachusetts since the enactment of the Marine Mammal Protection Act in 1972.^[51] Currently very little is known about the hunting and movement patterns of great whites off Cape Cod, but ongoing studies hope to offer insight into this growing shark population.^[52] The Massachusetts Division of Marine Fisheries (part of the Department of Fish and Game) began a population study in 2014; since 2019, this research has focused on how humans can avoid conflict with sharks.^[53] Scientists believe all North Atlantic great white sharks spend their first year of life near New York City, off the coast of Long Island.^[54]

A 2018 study indicated that white sharks prefer to congregate deep in anticycloniceddies in the North Atlantic Ocean. The sharks studied tended to favour the warm-water eddies, spending the daytime hours at depths of 450 m (1,480 ft) and coming to the surface at night.^[55]

Anatomy and appearance

The great white shark has a robust, large, conical snout. The upper and lower lobes on the tail fin are approximately the same size which is similar to some mackerel sharks. A great white displays countershading, by having a white underside and a grey dorsal area (sometimes in a brown or blue shade) that gives an overall mottled appearance. The coloration makes it difficult for prey to spot the shark because it breaks up the shark's outline when seen from the side. From above, the darker shade blends with the sea and from below it exposes a minimal silhouette against the sunlight.

Leucism is extremely rare in this species, but has been documented at least three times; in a pup that washed ashore in Australia and died,^[56] in another pup in South Africa,^[57] and a third six-metre adult male in Indonesia.^[58] Great white sharks, like many other sharks, have rows of serrated teeth behind the main ones, ready to replace any that break off. When the shark bites, it shakes its head side-to-side, helping the teeth saw off large chunks of flesh.^[59] Great white sharks, like other mackerel sharks, have larger eyes than other shark species in proportion to their body size. The iris of the eye is a deep blue instead of black.^[60]

Size

In great white sharks, sexual dimorphism is present, and females are generally larger than males. Male great whites on average measure 3.4 to 4.0 m (11 to 13 ft) in length, while females measure 4.6 to 4.9 m (15 to 16 ft).^[5] Adults of this species weigh 522–771 kg (1,151–1,700 lb) on average;^[63] however, mature females can have an average mass of 680–1,110 kg (1,500–2,450 lb).^[4] The largest females have been verified up to 6.1 m (20 ft) in length and an estimated 1,905 kg (4,200 lb) in weight,^[4] perhaps up to 2,268 kg (5,000 lb).^[64] The maximum size is subject to debate because some reports are rough estimations or speculations performed under questionable circumstances.^[65] Among living cartilaginous fish, only the whale shark (Rhincodon typus), the basking shark (Cetorhinus maximus) and the giant manta ray (Manta birostris), in that order, are on average larger and heavier. These three species are generally quite docile in disposition and given to passively filter-feeding on very small organisms.^[63] This makes the great white shark the largest extant macropredatory fish. Great white sharks measure approximately 1.2 m (3.9 ft) when born, and grow about 25 cm (9.8 in) every year.^[66]

A complete female great white shark specimen in the Museum of Zoology in Lausanne, and claimed by De Maddalena et al. (2003) as the largest preserved specimen, measured 5.83 m (19.1 ft) in total body length with the caudal fin in its depressed position, and is estimated to have weighed 2,000 kg (4,410 lb).^[3] According to J. E. Randall, the largest white shark reliably measured was a 5.94 m (19.5 ft) specimen reported from Ledge Point, Western Australia in 1987,^[67] but it is unclear whether that length was measured with the caudal fin in its depressed or natural position.^[3] Another great white specimen of similar size was a female caught in August 1988 in the Gulf of St. Lawrence, off Prince Edward Island, by David McKendrick of Alberton, Prince Edward Island. This female great white was 6.1 m (20 ft) long, as verified by the Canadian Shark Research Center.^[4]

A report of a specimen reportedly measuring 6.4 m (21 ft) in length and with a body mass estimated at 3,175–3,324 kg (7,000–7,328 lb)^[61][62][68] caught in 1945 off the coast of Cuba was at the time considered reliable by some experts.^{[62][69][68][70]} However, later studies revealed this particular specimen to be around 4.9 m (16 ft) in length, i.e. a specimen within the typical maximum size range.^[4]

The largest great white recognized by the International Game Fish Association (IGFA) is one caught by Alf Dean in southern Australian waters in 1959, weighing 1,208 kg (2,663 lb).^[65]

Examples of large unconfirmed great whites

A number of very large unconfirmed great white shark specimens have been recorded.^[71] For decades, many ichthyological works, as well as the Guinness Book of World Records, listed two great white sharks as the largest individuals: In the 1870s, a 10.9 m (36 ft) great white captured in southern Australian waters, near Port Fairy, and an 11.3 m (37 ft) shark trapped in a herringweir in New Brunswick, Canada, in the 1930s. However, these measurements were not obtained in a rigorous, scientifically valid manner, and researchers have questioned the reliability of these measurements for a long time, noting they were much larger than any other accurately reported sighting. Later studies proved these doubts to be well-founded. This New Brunswick shark may have been a misidentified basking shark, as the two have similar body shapes. The question of the Port Fairy shark was settled in the 1970s when J. E. Randall examined the shark's jaws and "found that the Port Fairy shark was of the order of 5 m (16 ft) in length and suggested that a mistake had been made in the original record, in 1870, of the shark's length".^[67]

While these measurements have not been confirmed, some great white sharks caught in modern times have been estimated to be more than 7 m (23 ft) long,^[72] but these claims have received some criticism.^[65][72] However, J. E. Randall believed that great white shark may have exceeded 6.1 m (20 ft) in length.^[67] A great white shark was captured near Kangaroo Island in Australia on 1 April 1987. This shark was estimated to be more than 6.9 m (23 ft) long by Peter Resiley,^[67][73] and has been designated as KANGA.^[72] Another great white shark was caught in Malta by Alfredo Cutajar on 16 April 1987. This shark was also estimated to be around 7.13 m (23.4 ft) long by John Abela and has been designated as MALTA.^[72][74] However, Cappo drew criticism because he used shark size estimation methods proposed by J. E. Randall to suggest that the KANGA specimen was 5.8–6.4 m (19–21 ft) long.^[72] In a similar fashion, I. K. Fergusson also used shark size estimation methods proposed by J. E. Randall to suggest that the MALTA specimen was 5.3–5.7 m (17–19 ft) long.^[72] However, photographic evidence suggested that these specimens were larger than the size estimations yielded through Randall's methods.^[72] Thus, a team of scientists—H. F. Mollet, G. M. Cailliet, A. P. Klimley, D. A. Ebert, A. D. Testi, and L. J. V. Compagno—reviewed the cases of the KANGA and MALTA specimens in 1996 to resolve the dispute by conducting a comprehensive morphometric analysis of the remains of these sharks and re-examination of photographic evidence in an attempt to validate the original size estimations and their findings were consistent with them. The findings indicated that estimations by P. Resiley and J. Abela are reasonable and could not be ruled out.^[72] A particularly large female great white nicknamed "Deep Blue", estimated measuring at 6.1 m (20 ft) was filmed off Guadalupe during shooting for the 2014 episode of Shark Week "Jaws Strikes Back". Deep Blue would also later gain significant attention when she was filmed interacting with researcher Mauricio Hoyas Pallida in a viral video that Mauricio posted on Facebook on 11 June 2015.^[75] Deep Blue was later seen off Oahu in January 2019 while scavenging a sperm whale carcass, whereupon she was filmed swimming beside divers including dive tourism operator and model Ocean Ramsey in open water.^[76][77][78] A particularly infamous great white shark, supposedly of record proportions, once patrolled the area that comprises False Bay, South Africa, was said to be well over 7 m (23 ft) during the early 1980s. This shark, known locally as the "Submarine", had a legendary reputation that was supposedly well-founded. Though rumours have stated this shark was exaggerated in size or non-existent altogether, witness accounts by the then young Craig Anthony Ferreira, a notable shark expert in South Africa, and his father indicate an unusually large animal of considerable size and power (though it remains uncertain just how massive the shark was as it escaped capture each time it was hooked). Ferreira describes the four encounters with the giant shark he participated in with great detail in his book Great White Sharks On Their Best Behavior.^[79]

One contender in maximum size among the predatory sharks is the tiger shark (Galeocerdo cuvier). While tiger sharks, which are typically both a few feet smaller and have a leaner, less heavy body structure than white sharks, have been confirmed to reach at least 5.5 m (18 ft) in the length, an unverified specimen was reported to have measured 7.4 m (24 ft) in length and weighed 3,110 kg (6,860 lb), more than two times heavier than the largest confirmed specimen at 1,524 kg (3,360 lb).^[63][80][81] Some other macropredatory sharks such as the Greenland shark (Somniosus microcephalus) and the Pacific sleeper shark (S. pacificus) are also reported to rival these sharks in length (but probably weigh a bit less since they are more slender in build than a great white) in exceptional cases.^[82][83]

Reported sizes

Adaptations

Great white sharks, like all other sharks, have an extra sense given by the ampullae of Lorenzini which enables them to detect the electromagnetic field emitted by the movement of living animals. Great whites are so sensitive they can detect variations of half a billionth of a volt. At close range, this allows the shark to locate even immobile animals by detecting their heartbeat.^[101] Most fish have a less-developed but similar sense using their body's lateral line.^[102]

To more successfully hunt fast and agile prey such as sea lions, the great white has adapted to maintain a body temperature warmer than the surrounding water. One of these adaptations is a "rete mirabile" (Latin for "wonderful net"). This close web-like structure of veins and arteries, located along each lateral side of the shark, conserves heat by warming the cooler arterial blood with the venous blood that has been warmed by the working muscles. This keeps certain parts of the body (particularly the stomach) at temperatures up to 14 °C (25 °F)^[103] above that of the surrounding water, while the heart and gills remain at sea temperature. When conserving energy, the core body temperature can drop to match the surroundings. A great white shark's success in raising its core temperature is an example of gigantothermy. Therefore, the great white shark can be considered an endothermicpoikilotherm or mesotherm because its body temperature is not constant but is internally regulated.^[59][104] Great whites also rely on the fat and oils stored within their livers for long-distance migrations across nutrient-poor areas of the oceans.^[105] Studies by Stanford University and the Monterey Bay Aquarium published on 17 July 2013 revealed that in addition to controlling the sharks' buoyancy, the liver of great whites is essential in migration patterns. Sharks that sink faster during drift dives were revealed to use up their internal stores of energy quicker than those which sink in a dive at more leisurely rates.^[106]

Toxicity from heavy metals seems to have little negative effects on great white sharks. Blood samples taken from forty-three individuals of varying size, age and sex off the South African coast led by biologists from the University of Miami in 2012 indicates that despite high levels of mercury, lead, and arsenic, there was no sign of raised white blood cell count and granulate to lymphocyte ratios, indicating the sharks had healthy immune systems. This discovery suggests a previously unknown physiological defence against heavy metal poisoning. Great whites are known to have a propensity for "self-healing and avoiding age-related ailments".^[107]

Bite force

A 2007 study from the University of New South Wales in Sydney, Australia, used CT scans of a shark's skull and computer models to measure the shark's maximum bite force. The study reveals the forces and behaviours its skull is adapted to handle and resolves competing theories about its feeding behaviour.^[108] In 2008, a team of scientists led by Stephen Wroe conducted an experiment to determine the great white shark's jaw power and findings indicated that a specimen massing 3,324 kg (7,328 lb) could exert a bite force of 18,216 newtons (4,095 lbf).^[68]

Ecology and behaviour

This shark's behaviour and social structure are complex. In South Africa, white sharks have a dominance hierarchy where an individual's rank is primarily established by their size, and to a lesser extent, their sex and "squatter's rights"; larger sharks dominate smaller sharks, females dominate males, and established residents dominate newcomers. When hunting, great whites tend to separate and resolve conflicts with rituals and displays. White sharks rarely resort to combat, although some individuals have been found with bite marks that match those of other white sharks. This suggests that when a great white approaches too closely to another, they react with a warning bite. Another possibility is that white sharks bite to show their dominance.^[109] Data acquired from animal-borne telemetry receivers and published in 2022 via the journal Royal Society Publishing suggests that individual great whites may associate so that they can inadvertently share information on the whereabouts of prey or the location of the remains of animals that can be scavenged. As biologging can help to reveal social habits, it allows a better understanding to be made in future studies regarding the full extent of social interactions in large marine animals, including the great white shark.^[110]

The great white shark is one of only a few sharks known to regularly lift its head above the sea surface to gaze at other objects such as prey. This is known as spy-hopping. This behaviour has also been seen in at least one group of blacktip reef sharks, but this might be learned from interaction with humans (it is theorized that the shark may also be able to smell better this way because smell travels through air faster than through water). White sharks are generally very curious animals, display intelligence and may also turn to socializing if the situation demands it. At Seal Island, white sharks have been observed arriving and departing in stable "clans" of two to six individuals on a yearly basis. Whether clan members are related is unknown, but they get along peacefully enough. In fact, the social structure of a clan is probably most aptly compared to that of a wolf pack, in that each member has a clearly established rank and each clan has an alpha leader. When members of different clans meet, they establish social rank nonviolently through any of a variety of interactions.^[109] In 2022, research in South Africa suggested that the great white shark has the ability to change colours to camouflage itself depending on the hormones it gives off. Different hormones would change the colour of the skin from white to grey. Skin dosed with adrenaline would turn lighter, with melanocyte-stimulating hormone causing melanocyte cells to dissipate thus making the shark's skin a darker colour, although hormone mediated color change is not fully validated due to the limited number of test subjects (i.e. great whites).^[111] The camo shark hypothesis is supported by the fact that zebra sharks can change their colour as they age, and rainbow sharks can lose colour due to stress and ageing.^[112]

Diet

Great white sharks are generalist carnivores,^[113] preying upon fish (e.g. tuna, rays, other sharks),^[109]cetaceans (i.e., dolphins, porpoises, whales), pinnipeds (e.g. seals, fur seals,^[109] and sea lions), squid, sea turtles,^[109]sea otters (Enhydra lutris) and seabirds.^[114][115] Great whites have also been known to eat objects that they are unable to digest. Juvenile white sharks predominantly prey on fish, including other elasmobranchs, as their jaws are not strong enough to withstand the forces required to attack larger prey such as pinnipeds and cetaceans until they reach a length of 3 m (9.8 ft) or more, at which point their jaw cartilage mineralizes enough to withstand the impact of biting into larger prey species.^[116] Upon approaching a length of nearly 4 m (13 ft), great white sharks begin to target predominantly marine mammals for food, though individual sharks seem to specialize in different types of prey depending on their preferences.^[117][118] They seem to be highly opportunistic.^[119][120] These sharks prefer prey with a high content of energy-rich fat. Shark expert Peter Klimley used a rod-and-reel rig and trolled carcasses of a seal, a pig, and a sheep from his boat in the South Farallons. The sharks attacked all three baits but rejected the sheep carcass.^[121]

Off Seal Island, False Bay in South Africa, the sharks ambush brown fur seals (Arctocephalus pusillus) from below at high speeds, hitting the seal mid-body. They achieve high speeds that allow them to completely breach the surface of the water. The peak burst speed is estimated to be above 40 km/h (25 mph).^[122] They have also been observed chasing prey after a missed attack. Prey is usually attacked at the surface.^[123] Shark attacks occur most often in the morning, within two hours of sunrise, when visibility is poor. Their success rate is 55% in the first two hours, falling to 40% in late morning after which hunting stops.^[109]

Off California, sharks use different predation techniques depending on the prey species.^[124] They immobilize northern elephant seals (Mirounga angustirostris) with a large bite to the hindquarters (which is the main source of the seal's mobility) and wait for the seal to bleed to death. This technique is especially used on adult male elephant seals, which are typically larger than the shark, ranging between 1,500 and 2,000 kg (3,300 and 4,400 lb), and are potentially dangerous adversaries.^[125][126] However, juvenile elephant seals are the most frequently eaten at elephant seal colonies.^[127] Prey is normally attacked sub-surface. Harbor seals (Phoca vitulina) are taken from the surface and dragged down until they stop struggling. They are then eaten near the bottom. California sea lions (Zalophus californianus) are ambushed from below and struck mid-body before being dragged and eaten.^[128]

In the Northwest Atlantic mature great whites are known to feed on both harbor and grey seals.^[51] Unlike adults, juvenile white sharks in the area feed on smaller fish species until they are large enough to prey on marine mammals such as seals.^[129]

White sharks also attack dolphins and porpoises from above, behind or below to avoid being detected by their echolocation. Targeted species include dusky dolphins (Sagmatias obscurus),^[72]Risso's dolphins (Grampus griseus),^[72]bottlenose dolphins (Tursiops ssp.),^[72][130]humpback dolphins (Sousa ssp.),^[130]harbour porpoises (Phocoena phocoena),^[72] and Dall's porpoises (Phocoenoides dalli).^[72] Groups of dolphins have occasionally been observed defending themselves from sharks with mobbing behaviour.^[130] White shark predation on other species of small cetacean has also been observed. In August 1989, a 1.8 m (5.9 ft) juvenile male pygmy sperm whale (Kogia breviceps) was found stranded in central California with a bite mark on its caudal peduncle from a great white shark.^[131] In addition, white sharks attack and prey upon beaked whales.^[72][130] Cases where an adult Stejneger's beaked whale (Mesoplodon stejnegeri), with a mean mass of around 1,100 kg (2,400 lb),^[132] and a juvenile Cuvier's beaked whale (Ziphius cavirostris), an individual estimated at 3 m (9.8 ft), were hunted and killed by great white sharks have also been observed.^[133] When hunting sea turtles, they appear to simply bite through the carapace around a flipper, immobilizing the turtle. The heaviest species of bony fish, the oceanic sunfish (Mola mola), has been found in great white shark stomachs.^[119]

Whale carcasses comprise an important part of the diet of white sharks. However, this has rarely been observed due to whales dying in remote areas. It has been estimated that 30 kg (66 lb) of whale blubber could feed a 4.5 m (15 ft) white shark for 1.5 months. Detailed observations were made of four whale carcasses in False Bay between 2000 and 2010. Sharks were drawn to the carcass by chemical and odour detection, spread by strong winds. After initially feeding on the whale caudal peduncle and fluke, the sharks would investigate the carcass by slowly swimming around it and mouthing several parts before selecting a blubber-rich area. During feeding bouts of 15–20 seconds the sharks removed flesh with lateral headshakes, without the protective ocular rotation they employ when attacking live prey. The sharks were frequently observed regurgitating chunks of blubber and immediately returning to feed, possibly in order to replace low energy yield pieces with high energy yield pieces, using their teeth as mechanoreceptors to distinguish them. After feeding for several hours, the sharks appeared to become lethargic, no longer swimming to the surface; they were observed mouthing the carcass but apparently unable to bite hard enough to remove flesh, they would instead bounce off and slowly sink. Up to eight sharks were observed feeding simultaneously, bumping into each other without showing any signs of aggression; on one occasion a shark accidentally bit the head of a neighbouring shark, leaving two teeth embedded, but both continued to feed unperturbed. Smaller individuals hovered around the carcass eating chunks that drifted away. Unusually for the area, large numbers of sharks over five metres long were observed, suggesting that the largest sharks change their behaviour to search for whales as they lose the manoeuvrability required to hunt seals. The investigating team concluded that the importance of whale carcasses, particularly for the largest white sharks, has been underestimated.^[134]

In another documented incident, white sharks were observed scavenging on a whale carcass alongside tiger sharks.^[135] In 2020, marine biologists Sasha Dines and Enrico Gennari published a documented incident in the journal Marine and Freshwater Research of two great white sharks within an hour apart, successfully attacking and killing a live juvenile 7 m (23 ft) humpback whale. The sharks utilized the classic attack strategy used on pinnipeds when attacking the whale, even utilizing the bite-and-spit tactic they employ on smaller prey items. The whale was an entangled individual, heavily emaciated and thus more vulnerable to the sharks' attacks. The incident is the first known documentation of great whites actively killing a large baleen whale.^[136][137] A second incident regarding great white sharks killing humpback whales involving a single large female great white nicknamed Helen was documented off the coast of South Africa. Working alone, the shark attacked a 33 ft (10 m) emaciated and entangled humpback whale by attacking the whale's tail to cripple it before she managed to drown the whale by biting onto its head and pulling it underwater. The attack was witnessed via aerial drone by marine biologist Ryan Johnson, who said the attack went on for roughly 50 minutes before the shark successfully killed the whale. Johnson suggested that the shark may have strategized its attack in order to kill such a large animal.^[138][139]

Stomach contents of great whites also indicates that whale sharks both juvenile and adult may also be included on the animal's menu, though whether this is active hunting or scavenging is not known at present.^[140][141]

Reproduction

Great white sharks were previously thought to reach sexual maturity at around 15 years of age, but are now believed to take far longer; male great white sharks reach sexual maturity at age 26, while females take 33 years to reach sexual maturity.^{[8][142][143]} Maximum life span was originally believed to be more than 30 years, but a study by the Woods Hole Oceanographic Institution placed it at upwards of 70 years. Examinations of vertebral growth ring count gave a maximum male age of 73 years and a maximum female age of 40 years for the specimens studied. The shark's late sexual maturity, low reproductive rate, long gestation period of 11 months and slow growth make it vulnerable to pressures such as overfishing and environmental change.^[7]

Little is known about the great white shark's mating habits, and mating behaviour had not been observed in this species until 1997 and properly documented in 2020. It was assumed previously to be possible that whale carcasses are an important location for sexually mature sharks to meet for mating.^[134] According to the testimony of fisherman Dick Ledgerwood, who observed two great white sharks mating in the area near Port Chalmers and Otago Harbor, in New Zealand, it is theorized that great white sharks mate in shallow water away from feeding areas and continually roll belly to belly during copulation.^[144] Birth has never been observed, but pregnant females have been examined. Great white sharks are ovoviviparous, which means eggs develop and hatch in the uterus and continue to develop until birth.^[145] The great white has an 11-month gestation period. The shark pup's powerful jaws begin to develop in the first month. The unborn sharks participate in oophagy, in which they feed on ova produced by the mother. Delivery is in spring and summer.^[146] The largest number of pups recorded for this species is 14 pups from a single mother measuring 4.5 m (15 ft) that was killed incidentally off Taiwan in 2019.^[147]

On 9 July 2023, the first footage of what was likely a newborn great white shark was filmed via aerial drone off of Southern California, off Carpinteria