Brief Overview of the Great White

Shark (Carcharodon carcharias)

Recognition
  • body heavy, spindle-shaped with conical snout and narrow tail stalk supported by stout lateral keels
  • long gill slits, extending about 2/3 the depth of the throat
  • mouth armed with teeth that are relatively few but large, triangular and serrated
  • second dorsal and anal fins small with pivoting bases
  • caudal fin lunate, with lower lobe nearly as large as the upper
  • eyes small but conspicuous, black with inconspicuous pupil
  • origin of first dorsal fin over rear base of pectoral fins
  • sharp demarcation between dark upper surfaces and white lower surfaces; trailing edge of pectoral fin white, underside of pectoral tips black; a black spot occurs at the pectoral axil ('armpit') in some individuals
Size
  • Pups are 39-59 in (100-150 cm) long at birth
  • Most individuals encountered are 12-16 ft (3.7-4.9 m) long. 
  • Maximum known length is at least 20 ft (6.1 m) and maximum known weight is more than 2,730 lb (1,240 kg), but individuals up to 23 feet (7.1 m) in length and 5,070 lb (2,300 kg) are probable. 
  • On a per-length basis, individuals from California waters seem more massive than those from other regions - a 17.6 ft (5.4 m) female captured off Pt. Vincente in September 1986 weighed 4,140 lbs (1,878 kg).
Reproduction
  • Reproductive Mode: ovoviviparous, with oophagy
  • Age at Maturity: males 9-10 yrs, females 14-16 yrs
  • Gestation Period: 14 months
  • Number of Pups: 2-10, possibly to 17
Diet
  • Juvenile: bottom-dwelling teleost fishes, small sharks and rays
  • Adult: sharks, rays, teleost fishes, seals, sea lions, dolphins, whale blubber (scavenged), squids, seabirds, marine turtles, crabs, snails
Range
  • Cosmopolitan in cold temperate to tropical seas
  • Perhaps the most widely distributed of living sharks, rivalled only by the Bluntnose Sixgill (Hexanchus griseus).
Habitat
  • Primarily a coastal and offshore inhabitant of continental and insular shelves, but large individuals have been recorded off oceanic islands; often occurs close inshore to the surfline and penetrates shallow bays in continental waters but also frequents offshore continental islands, especially those with pinniped colonies.
  • Known depth range is from the surface to at least 6,150 ft (1,875 m). 
  • Seems to prefer waters with sea surface temperatures of 59-72 F (15-22 C); known sea surface temperature range is 45-81 degrees F (7-27 C); probable bottom temperature at maximum recorded depth is 39 F (4 C).
Predators
  • Humans represent the greatest threat, but this species is occasionally preyed upon by Killer Whales (Orcinus orca) and larger conspecifics.
Danger to Humans
  • Extreme; this species is responsible for the vast majority of unprovoked attacks on humans (surfers, divers, swimmers, and kayakers) along the Pacific Coast, many of them fatal
Utilization
  • Fishing: classed as a gamefish, this huge and powerful shark requires specialized equipment and tactics, including fighting chair, 130-lb (60-kg) test line, 20-ft (6-m) wire leader, 12/0 reel, and extensive use of chum to attract it to the boat.
  • Curios:  jaws and teeth are much sought-after, fetching high prices.
  • Eco-Tourism: thriving eco-tourism industries have developed in scattered locations around the globe, including (most notably) off South Australia, South Africa, and off California.  There is currently much conflict between tour operators, who argue that they and their clients have a right to observe White Sharks in the wild, and researchers who argue that tourism activities interferes with their work.
Relative Abundance
  • Rare to sporadic compared with other sharks, but often seasonally abundant near large pinniped rookeries on offshore islands
Conservation Status
  • A regionally protected species off South Africa, Namibia, Maldives, Australia, California, the US Atlantic Seaboard and Gulf Coast (including Florida), and in the Mediterranean (including off Malta), where it is illegal to pursue, capture, or possess in whole or in part. 
  • International protection under CITES has not yet been granted, allowing a sizable Black Market network to perpetuate sales of White Shark jaws and teeth.

 

The Great White Shark is one of the sea's paramount predators and a creature of deep fascination to many people. As sharks go, the Great White is huge and particularly beautiful, featuring bold pigmentation, dark eyes, and a built-in 'smile'. It also gives an impression of having a charming personality, a strange mix of curiosity and timidity that belies its enormity and power.

The Great White is among the most widely distributed of sharks, owing - in part - to its ability to maintain its body temperature up to 27F (15C) warmer than the surrounding seawater.

Great White Sharks often prey upon seals and sea lions in areas where they are locally abundant. Typically, a Great White stalks such prey from near the rocky bottom - where, from above, its black back is almost invisible against the dark substrate - and attacks in a sudden vertical rush, often leaping from the water in a spectacular explosion of spray and blood.

Young juveniles of this species (less than 5 feet or 1.5 metres in length) possess relatively slender teeth with a small basal cusplet on either side of the main blade. Such teeth are well suited to grasping the bottom-dwelling fishes on which they predominantly feed.

Although adults of this species are best-known as predators of marine mammals, Great Whites are predominantly fish-eaters throughout their lives - but even large individuals will take small prey opportunistically.

Highly curious and exploratory, Great White Sharks often investigate novel objects in their environment - first visually and, if nothing too frightening occurs, eventually by gentle mouthing (a habit which can prove fatal for humans) - and will scavenge whenever possible.

At whale carcasses, this generally solitary species often establishes temporary social hierarchies which are based largely on size. Among similar-sized individuals, the social hierarchy is maintained through a subtle form of body language.

Recent research has demonstrated that Great Whites are socially complex, featuring such behaviors as parallel swimming, jaw gaping, pectoral fin depression, and even splash-fights.

The Great White is also unusual among sharks in that it sometimes raises its head out of the water, apparently to observe activity above the surface.

Due to its curiosity about floating objects and predation upon marine mammals (which are air-breathing and must surface to ventilate their lungs), the Great White is more likely to be observed by surface-bound people than are most sharks.

Divers occasionally encounter solitary Great Whites underwater. Usually, the shark seems to check them out visually, becomes disinterested after a few passes, and swims away. However, one must not count on it: this is a potentially very dangerous wild animal and divers who encounter one while diving would be wise to leave the water immediately.

Despite the enormous popular and scientific interest in the Great White, it remains one of the least understood of the sea's creatures. It's highly seductive combination of large size, charisma, menace and mystery, make the Great White Shark a modern day 'monster' that many people find irresistible.

 

ReefQuest Centre for Shark Research
Text and illustrations R. Aidan Martin
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