Editing Great white shark (section)

=== Diet ===
[[File:A beachcomber is looking at the marks of great white sharks bites.jpg|thumb|A beachcomber looking at bite marks from a great white shark on a beached [[whale]] carcass]]

Great white sharks are generalist [[carnivorous|carnivores]],<ref>{{Cite journal |last1=Collareta |first1=Alberto |last2=Casati |first2=Simone |last3=Di Cencio |first3=Andrea |last4=Bianucci |first4=Giovanni |date=20 October 2023 |title=The Deep Past of the White Shark, Carcharodon carcharias, in the Mediterranean Sea: A Synthesis of Its Palaeobiology and Palaeoecology |journal=[[Life (journal)|Life]] |language=en |volume=13 |issue=10 |pages=2085 |doi=10.3390/life13102085 |doi-access=free |issn=2075-1729 |pmc=10608139 |pmid=37895466 |bibcode=2023Life...13.2085C }}</ref> preying upon [[fish]] (e.g. [[tuna]], [[Batoidea|rays]], other [[shark]]s),<ref name="NHmag" /> [[cetaceans]] (i.e., [[dolphin]]s, [[porpoise]]s, [[whale]]s), [[pinniped]]s (e.g. [[Earless seal|seals]], [[fur seal]]s,<ref name="NHmag" /> and [[sea lion]]s), [[squid]], [[sea turtle]]s,<ref name="NHmag" /> [[sea otter]]s (''Enhydra lutris'') and [[seabirds]].<ref>{{cite journal |last=Johnson |first=R. L. |author2=Venter, A. |author3=Bester, M.N. |author4=Oosthuizen, W.H. |title=Seabird predation by white shark ''Carcharodon carcharias'' and Cape fur seal ''Arctocephalus pusillus pusillus'' at Dyer Island |journal=South African Journal of Wildlife Research |volume=36 |issue=1 |pages=23–32 |location=South Africa |year=2006 |url=http://www.oceans-research.com/media/publications/SeabirdPublishedManuscript.pdf|url-status=dead|archive-url=https://web.archive.org/web/20120403003541/http://www.oceans-research.com/media/publications/SeabirdPublishedManuscript.pdf|archive-date=3 April 2012}}</ref><ref>{{Cite web |url=https://animaldiversity.org/accounts/Carcharodon_carcharias/ |title=Carcharodon carcharias (Great white shark) |website=[[Animal Diversity Web]] |access-date=15 August 2019 |archive-date=9 August 2019 |archive-url=https://web.archive.org/web/20190809141531/http://animaldiversity.org/accounts/Carcharodon_carcharias/ |url-status=live}}</ref> 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 {{cvt|3|m|ft}} or more, at which point their jaw cartilage mineralizes enough to withstand the impact of biting into larger prey species.<ref>{{Cite web |title=Teenage great white sharks are awkward biters |url=https://www.sciencedaily.com/releases/2010/12/101202124556.htm |access-date=6 February 2023 |date=2 December 2010 |website=ScienceDaily |language=en |archive-date=21 June 2023 |archive-url=https://web.archive.org/web/20230621083517/https://www.sciencedaily.com/releases/2010/12/101202124556.htm |url-status=live}}</ref> Upon approaching a length of nearly {{cvt|4|m|ft}}, great white sharks begin to target predominantly [[marine mammal]]s for food, though individual sharks seem to specialize in different types of prey depending on their preferences.<ref>{{Cite web |title=White shark diets show surprising variability, vary with age and among individuals |date=29 December 2012 |url=https://www.sciencedaily.com/releases/2012/09/120929140238.htm |access-date=6 February 2023 |website=ScienceDaily |language=en |archive-date=21 June 2023 |archive-url=https://web.archive.org/web/20230621083518/https://www.sciencedaily.com/releases/2012/09/120929140238.htm |url-status=live}}</ref><ref name="Feeding">{{cite journal |last=Estrada |first=J. A. |author2=Rice, Aaron N. |author3=Natanson, Lisa J. |author4=Skomal, Gregory B. |title=Use of isotopic analysis of vertebrae in reconstructing ontogenetic feeding ecology in white sharks |journal=Ecology |volume=87 |issue=4 |pages=829–834 |year=2006 |doi=10.1890/0012-9658(2006)87[829:UOIAOV]2.0.CO;2 |pmid=16676526}}</ref> They seem to be highly opportunistic.<ref name=Ferguson>{{cite journal |last1=Fergusson |first1=I. K. |last2=Compagno |first2=L. J. |last3=Marks |first3=M. A. |year=2000 |title=Predation by white sharks ''Carcharodon carcharias'' (Chondrichthyes: Lamnidae) upon chelonians, with new records from the Mediterranean Sea and a first record of the ocean sunfish ''Mola mola'' (Osteichthyes: Molidae) as stomach contents |doi=10.1023/a:1007639324360 |journal=Environmental Biology of Fishes |volume=58 |issue=4 |pages=447–453 |bibcode=2000EnvBF..58..447F |s2cid=31232421}}</ref><ref name=Hussey>Hussey, N. E., McCann, H. M., Cliff, G., Dudley, S. F., Wintner, S. P., & Fisk, A. T. (2012). Size-based analysis of diet and trophic position of the white shark (''Carcharodon carcharias'') in South African waters. ''Global Perspectives on the Biology and Life History of the White Shark''. (Ed. ML Domeier.) pp. 27–49.</ref> 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 [[Farallon Islands|Farallons]]. The sharks attacked all three baits but rejected the sheep carcass.<ref>{{cite web |url=http://www.elasmo-research.org/education/topics/b_catch.htm |title=Catch as Catch Can |publisher=ReefQuest Centre for Shark Research |access-date=16 October 2010 |archive-date=25 October 2018 |archive-url=https://web.archive.org/web/20181025172903/http://www.elasmo-research.org/education/topics/b_catch.htm |url-status=live}}</ref>

Off [[Seal Island, South Africa|Seal Island]], [[False Bay]] in South Africa, the sharks ambush [[brown fur seal]]s (''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 {{cvt|40|km/h|mph}}.<ref>{{cite web |url=http://www.elasmo-research.org/education/topics/p_shark_speed.htm |title=How Fast Can a Shark Swim? |publisher=ReefQuest Centre for Shark Research |access-date=21 February 2009 |archive-date=21 October 2018 |archive-url=https://web.archive.org/web/20181021025349/http://www.elasmo-research.org/education/topics/p_shark_speed.htm |url-status=live}}</ref> They have also been observed chasing prey after a missed attack. Prey is usually attacked at the surface.<ref>{{cite web |url=http://www.elasmo-research.org/education/white_shark/predation.htm |title=White Shark Predatory Behavior at Seal Island |publisher=ReefQuest Centre for Shark Research |access-date=11 September 2008 |archive-date=4 July 2018 |archive-url=https://web.archive.org/web/20180704225829/http://www.elasmo-research.org/education/white_shark/predation.htm |url-status=live}}</ref> 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.<ref name="NHmag" />

Off California, sharks use different predation techniques depending on the prey species.<ref>{{Cite book |last=Casey |first=Susan |title=The devil's teeth: a true story of obsession and survival among America's great white sharks |date=2005 |publisher=H. Holt |isbn=978-0-8050-7581-6 |edition=1st |location=New York}}</ref> They immobilize [[northern elephant seal]]s (''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 {{cvt|1500|and|2000|kg}}, and are potentially dangerous adversaries.<ref>{{cite journal |last1=Le Boeuf |first1=B. J. |last2=Crocker |first2=D. E. |last3=Costa |first3=D. P. |last4=Blackwell |first4=S. B. |last5=Webb |first5=P. M. |last6=Houser |first6=D. S. |year=2000 |title=Foraging ecology of northern elephant seals |journal=Ecological Monographs |volume=70 |issue=3 |pages=353–382 |doi=10.2307/2657207 |jstor=2657207 |bibcode=2000EcoM...70..353B}}</ref><ref>{{cite journal |last1=Haley |first1=M. P. |last2=Deutsch |first2=C. J. |last3=Le Boeuf |first3=B. J. |year=1994 |title=Size, dominance and copulatory success in male northern elephant seals, ''Mirounga angustirostris'' |journal=Animal Behaviour |volume=48 |issue=6 |pages=1249–1260 |doi=10.1006/anbe.1994.1361 |s2cid=54388167}}</ref> However, juvenile elephant seals are the most frequently eaten at elephant seal colonies.<ref>{{cite journal |last1=Weng |first1=K. C. |last2=Boustany |first2=A. M. |last3=Pyle |first3=P. |last4=Anderson |first4=S. D. |last5=Brown |first5=A. |last6=Block |first6=B. A. |year=2007 |title=Migration and habitat of white sharks (''Carcharodon carcharias'') in the eastern Pacific Ocean |journal=Marine Biology |volume=152 |issue=4 |pages=877–894 |doi=10.1007/s00227-007-0739-4 |bibcode=2007MarBi.152..877W |s2cid=39985022}}</ref> Prey is normally attacked sub-surface. [[Harbor seal]]s (''Phoca vitulina'') are taken from the surface and dragged down until they stop struggling. They are then eaten near the bottom. [[California sea lion]]s (''Zalophus californianus'') are ambushed from below and struck mid-body before being dragged and eaten.<ref>{{cite web |last=Martin |first=Rick |url=http://www.sharkresearchcommittee.com/predation.htm |title=Predatory Behavior of Pacific Coast White Sharks |publisher=Shark Research Committee|url-status=dead |archive-url=https://web.archive.org/web/20120730155219/http://www.sharkresearchcommittee.com/predation.htm |archive-date=30 July 2012}}</ref>

[[File:Great white shark Dyer Island.jpg|thumb|left|Great white shark near [[Gansbaai]], showing upper and lower teeth]]
In the Northwest Atlantic mature great whites are known to feed on both [[Harbor seal|harbor]] and [[Grey seal|grey]] seals.<ref name=":0" /> 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.<ref>{{Cite web |url=https://animaldiversity.org/accounts/Carcharodon_carcharias/ |title=''Carcharodon carcharias'' (Great white shark) |last1=Chewning |first1=Dana |last2=Hall |first2=Matt |website=Animal Diversity Web |language=en |access-date=15 August 2019 |archive-date=9 August 2019 |archive-url=https://web.archive.org/web/20190809141531/http://animaldiversity.org/accounts/Carcharodon_carcharias/ |url-status=live}}</ref>

White sharks also attack dolphins and porpoises from above, behind or below to avoid being detected by their [[Animal echolocation#Whales|echolocation]]. Targeted species include [[dusky dolphin]]s (''Sagmatias obscurus''),<ref name="GWS" /> [[Risso's dolphin]]s (''Grampus griseus''),<ref name="GWS" /> [[bottlenose dolphin]]s (''Tursiops'' ssp.),<ref name="GWS" /><ref name="Competition">{{cite journal |last=Heithaus |first=Michael |title=Predator–prey and competitive interactions between sharks (order Selachii) and dolphins (suborder Odontoceti): a review |journal=Journal of Zoology |volume=253 |pages=53–68 |year=2001 |url=http://www.science.fau.edu/sharklab/courses/elasmobiology/readings/heithaus.pdf |doi=10.1017/S0952836901000061 |access-date=26 February 2010 |citeseerx=10.1.1.404.130 |archive-url=https://web.archive.org/web/20160115113304/http://www.science.fau.edu/sharklab/courses/elasmobiology/readings/heithaus.pdf |archive-date=15 January 2016 |url-status=dead}}</ref> [[humpback dolphin]]s (''Sousa'' ssp.),<ref name="Competition" /> [[harbour porpoise]]s (''Phocoena phocoena''),<ref name="GWS" /> and [[Dall's porpoise]]s (''Phocoenoides dalli'').<ref name="GWS" /> Groups of dolphins have occasionally been observed defending themselves from sharks with mobbing behaviour.<ref name="Competition" /> White shark predation on other species of small cetacean has also been observed. In August 1989, a {{cvt|1.8|m|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.<ref>{{cite journal |last=Long |first=Douglas |title=Apparent Predation by a White Shark ''Carcharodon carcharias'' on a Pygmy Sperm Whale ''Kogia breviceps'' |journal=Fishery Bulletin |volume=89 |pages=538–540 |year=1991 |url=http://fishbull.noaa.gov/893/long.pdf |archive-url=https://web.archive.org/web/20080916023842/http://fishbull.noaa.gov/893/long.pdf |archive-date=16 September 2008 |url-status=live}}</ref> In addition, white sharks attack and prey upon [[beaked whale]]s.<ref name="GWS" /><ref name="Competition" /> Cases where an adult [[Stejneger's beaked whale]] (''Mesoplodon stejnegeri''), with a mean mass of around {{cvt|1100|kg}},<ref>Kays, R. W., & Wilson, D. E. (2009). ''Mammals of North America''. Princeton University Press.</ref> and a juvenile [[Cuvier's beaked whale]] (''Ziphius cavirostris''), an individual estimated at {{cvt|3|m|ft}}, were hunted and killed by great white sharks have also been observed.<ref>{{cite journal |last1=Baird |first1=R. W. |last2=Webster |first2=D. L. |last3=Schorr |first3=G. S. |last4=McSweeney |first4=D. J. |last5=Barlow |first5=J. |year=2008 |title=Diet variation in beaked whale diving behavior |url=http://www.cascadiaresearch.org/robin/Bairdetal2007beakedwhales.pdf |archive-url=https://web.archive.org/web/20080221215013/http://www.cascadiaresearch.org/Robin/Bairdetal2007beakedwhales.pdf |archive-date=21 February 2008 |url-status=live |journal=Marine Mammal Science |volume=24 |issue=3 |pages=630–642 |doi=10.1111/j.1748-7692.2008.00211.x |bibcode=2008MMamS..24..630B |hdl=10945/697 |s2cid=9876850}}</ref> 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.<ref name="Ferguson" />

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 {{cvt|30|kg}} of whale blubber could feed a {{cvt|4.5|m|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 (tail)|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.<ref name="KrkosekFallows2013">{{cite journal |last1=Krkosek |first1=Martin |last2=Fallows |first2=Chris |last3=Gallagher |first3=Austin J. |last4=Hammerschlag |first4=Neil |title=White Sharks (''Carcharodon carcharias'') Scavenging on Whales and Its Potential Role in Further Shaping the Ecology of an Apex Predator |journal=PLOS ONE |volume=8 |issue=4 |year=2013 |pages=e60797 |doi=10.1371/journal.pone.0060797 |pmid=23585850 |pmc=3621969 |bibcode=2013PLoSO...860797F|doi-access=free}}</ref>

[[File:White shark (Carcharodon carcharias) scavenging on whale carcass - journal.pone.0060797.g004-A.png|thumb|A shark scavenging on a whale carcass in [[False Bay]], South Africa]]
In another documented incident, white sharks were observed scavenging on a whale carcass alongside tiger sharks.<ref>{{cite web |last=Dudley |first=Sheldon F. J. |author2=Anderson-Reade, Michael D. |author3=Thompson, Greg S. |author4=McMullen, Paul B. |title=Concurrent scavenging off a whale carcass by great white sharks, ''Carcharodon carcharias'', and tiger sharks, ''Galeocerdo cuvier'' |work=Marine Biology |publisher=Fishery Bulletin |year=2000 |url=http://fishbull.noaa.gov/983/13.pdf |access-date=4 May 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100527182623/http://fishbull.noaa.gov/983/13.pdf |archive-date=27 May 2010}}</ref> 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&nbsp;m (23&nbsp;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.<ref>{{Cite journal |url=https://www.publish.csiro.au/mf/MF19291 |title=First observations of white sharks (''Carcharodon carcharias'') attacking a live humpback whale (''Megaptera novaeangliae'') |first1=Sasha |last1=Dines |first2=Enrico |last2=Gennari |date=29 January 2020 |journal=Marine and Freshwater Research |volume=71 |issue=9 |page=1205 |via=www.publish.csiro.au |doi=10.1071/MF19291 |s2cid=212969014 |access-date=17 May 2020 |archive-date=8 March 2021 |archive-url=https://web.archive.org/web/20210308080042/https://www.publish.csiro.au/mf/MF19291 |url-status=live}}</ref><ref>{{Cite web |url=https://www.forbes.com/sites/melissacristinamarquez/2020/03/12/first-observations-of-white-sharks-attacking-a-live-humpback-whale/ |title=First Observations Of White Sharks Attacking A Live Humpback Whale |first=Melissa Cristina |last=Márquez |website=Forbes |access-date=17 May 2020 |archive-date=19 April 2020 |archive-url=https://web.archive.org/web/20200419133138/https://www.forbes.com/sites/melissacristinamarquez/2020/03/12/first-observations-of-white-sharks-attacking-a-live-humpback-whale/ |url-status=live}}</ref> 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 {{Convert|33|ft|m|abbr=on}} 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 (marine scientist)|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.<ref>{{Cite web |url=https://www.independent.co.uk/news/world/africa/great-white-shark-drowns-humpback-whale-predator-south-africa-a9620251.html |title=Drone footage shows a great white shark drowning a 33ft humpback whale |date=15 July 2020 |website=The Independent |access-date=16 July 2020 |archive-date=18 July 2020 |archive-url=https://web.archive.org/web/20200718124150/https://www.independent.co.uk/news/world/africa/great-white-shark-drowns-humpback-whale-predator-south-africa-a9620251.html |url-status=live}}</ref><ref>{{Cite web |url=https://www.express.co.uk/news/science/1309559/shark-attack-great-white-shark-attack-humpback-whale-drone-video |title=Shark attack: Watch 'strategic' Great White hunt down and kill 10 Metre humpback whale |first=Tom |last=Fish |date=15 July 2020 |website=Express.co.uk |access-date=16 July 2020 |archive-date=18 July 2020 |archive-url=https://web.archive.org/web/20200718230137/https://www.express.co.uk/news/science/1309559/shark-attack-great-white-shark-attack-humpback-whale-drone-video |url-status=live}}</ref>

Stomach contents of great whites also indicates that [[whale shark]]s 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.<ref>{{cite web |url=https://www.newscientist.com/article/2077291-white-sharks-diet-may-include-biggest-fish-of-all-whale-shark/ |title=White shark's diet may include biggest fish of all: whale shark |first=Brian |last=Owens |work=New Scientist |date=12 February 2016 |access-date=13 February 2016 |archive-date=12 April 2016 |archive-url=https://web.archive.org/web/20160412232049/https://www.newscientist.com/article/2077291-white-sharks-diet-may-include-biggest-fish-of-all-whale-shark/ |url-status=live}}</ref><ref>{{cite journal |doi=10.1007/s12526-015-0430-9 |title=Whale shark on a white shark's menu |journal=Marine Biodiversity |volume=46 |issue=4 |pages=745 |year=2015 |last1=Moore |first1=G. I. |last2=Newbrey |first2=M. G. |s2cid=36426982}}</ref>