Sharks have several highly developed senses. Their primary sense is the ability to smell. They can detect a drop of blood in 100 liters of water. They also have the ability to detect electrical charges as small as 0.005 microvolts. Prey can be detected by the electrical field generated by a beating heart or gill action. Fish in hiding can also be detected this way. At feeding aggregations, such as 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. Great white sharks are also unusual among sharks in that they sometime rais their heads out of the water, apparently to observe activity above the surface.
Communication Channels: visual ; tactile ; chemical ; electric
Perception Channels: visual ; tactile ; chemical ; electric
Great white sharks are rare throughout their range. This, coupled with their low reproductive rates and persecution by humans means that the IUCN considers them vulnerable. Hunting and bycatch in commercial fisheries exerts significant pressure on great white shark populations and newer estimates may suggest that great white sharks should be considered endangered.
US Federal List: no special status
CITES: appendix ii
State of Michigan List: no special status
IUCN Red List of Threatened Species: vulnerable
There is not a lot of information about the development of great white sharks. While great white sharks develop in the uterus of the mother shark they eat other embryos and unfertilized eggs (Burnie and Wilson, 2001). When great white sharks are born they are approximately 1 to 1.5 meters in length. Around the age of 10 years, male great white sharks have matured to a length of about 4 meters. Females, on the other hand, mature later, around the age of 15 years, at a length of 4 to 5 meters (MarineBio, 2009).
Great white sharks can be dangerous to humans partaking in aquatic activities in the ocean such as swimming, diving, surfing, kayaking and canoeing. Great white sharks tend to attack swiftly with a single bite and then retreat. If the bite is minimal, the individual may have a chance to seek safety. However, if the bite is critical, damaging large organs or appendages, death can result for the victim. A review of great white shark attacks off the western United States showed that about 7 percent of attacks were fatal, but data from other localities, such as South Africa, show fatality rates of more than 20 percent. Fatality rates as high as 60 percent have been recorded from attacks in the waters off Australia. Many researchers maintain that attacks on humans stem from the shark’s curiosity. Other authorities contend that these attacks may be the result of the shark mistaking humans for its natural prey, such as seals and sea lions. It is also possible that great white sharks intend to attack humans where their normal prey may be scarce (Long, 2009).
Negative Impacts: injures humans (bites or stings)
Humans hunt great white sharks primarily for sport and for body parts. Great white sharks have developed a reputation in the media as being aggressive and ferocious and as a result they have become a highly prized sport fish. A fully intact jaw of a great white shark can be sold for thousands of dollars. Great white sharks are never abundant because they are at the top of their food chain. In areas that contain great white sharks, boaters and dive operators can earn a living from “shark tourism”. This “shark tourism” allows visitors to see great white sharks up close from the safety of a steel cage suspended in the water (Long, 2009). Traded products that come from great white sharks include fins, jaws, teeth and meat, cartilage, and skin for leather. Liver oil is used in medicines, and the carcass can be used for fish-meal and fertilizer.The trade in shark fins is generally on the increase with records from the Food and Agriculture Organization (FAO) of the United Nations indicating that the international fin trade increased significantly between 1980 and 1990. The demand for shark fin escalated further during the 1990s, making it one of the most expensive fishery products. Jaws and teeth are the most valuable great white shark products in trade.
Positive Impacts: food ; body parts are source of valuable material; ecotourism ; source of medicine or drug ; produces fertilizer
Great white sharks are apex predators, meaning they have a large affect on the populations of their prey including elephant seals and sea lions. Great white sharks are hosts to parasites such as copepods (Pandarus sinuatus and Pandarus smithii).
Commensal/Parasitic Species:
Young great white sharks typically feed on smaller species such as squid and stingrays, as well as other small sharks (McGrouther, 2008). As these fish mature their appetites change. The diet of adults consists primarily of seals, sealions, dolphins, and whale carcasses (McGrouther, 2008). One of the most frequent prey animals of great white sharks are elephant seals (MarineBio, 2009). Sometimes they feed on turtles and various sea birds (McGrouther, 2008). Great white sharks may attack with different 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 (MarineBio, 2009). 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. Great white sharks have been reported to attack humans but there have been as few as 311 verified deaths from great white shark attacks (Burnie and Wilson, 2001).
Animal Foods: birds; mammals; reptiles; fish; mollusks; other marine invertebrates
Primary Diet: carnivore (Eats terrestrial vertebrates, Piscivore , Molluscivore )
The geographic range of great white sharks is extremely wide. From 60°N latitude to 60°S latitude, they can be found in all cold temperate and tropical coastal waters. Great white sharks can be found in coastal waters along central California and off the western cape of South Africa. They have also been reported in North American coastal waters from Newfoundland to Florida and from Alaska to Southern Mexico (MarineBio, 2009). According to National Geographic Society (2009), there are no reliable data on great white shark population numbers.
Biogeographic Regions: indian ocean (Native ); atlantic ocean (Native ); pacific ocean (Native )
Other Geographic Terms: cosmopolitan
Great white sharks are primarily a coastal and offshore inhabitant of insular and continental shelves (Aidan Martin, 2003). Great white sharks have been known to breach the surface and have also been found at depths of 1,875 meters (Dale, 2008). They seem to prefer waters with sea surface temperatures of 59 to 72°F (Aidan Martin, 2003). They can be found on the following coastlines: California to Alaska, the east coast of the United States, coastal Gulf of Mexico, Hawaii, coasts of South America, South Africa, Australia (except the north coast), New Zealand, Mediterranean Sea, West Africa to Scandinavia, Japan, and the eastern coastline of China to Russia (Dale, 2008).
Range depth: 0 to 1,875m m.
Habitat Regions: temperate ; tropical ; saltwater or marine
Aquatic Biomes: coastal
The age of great white sharks can be determined by counting the rings that form on the vertebra. It is believed that great white sharks breed between the ages of 9 and 23 years old and that their lifespan is approximately 30 years (Levine, 1998). Various research indicates that great white sharks live somewhere between 30 and 40 years (Shark Information, 2009).
Average lifespan
Status: wild: 30 years.
Average lifespan
Status: wild: 30 years.
These massive predators reach lengths of 6 m long and weigh up to 3000 kg (McGouther, 2008). Female great white sharks tend to be larger than male great white sharks, who only reach lengths of approximately 4 m (Compagno, Dando and Fowler, 2005). The massive bodies of great white sharks are streamlined and powerful to generate bursts of speed. Their snouts are narrowed and somewhat pointed, and their eyes are onyx in color. These white bellied sharks have crescent shaped tails with long, nearly-symmetrical upper and lower lobes. The color of the dorsal side varies, dark gray to light gray. Great white sharks have a caudal fin and paired dorsal and pectoral fins that help to propel them through the water. The mouths of great white sharks are 0.9 to 1.2 m wide and the upper and bottom teeth work together when handling prey with the bottom teeth keeping the prey in place while the upper teeth tear into the flesh. Great white sharks are endothermic, generating body heat through metabolism (MarineBio, 2009).
Range mass: 3000 (high) kg.
Range length: 4 to 7 m.
Other Physical Features: endothermic ; bilateral symmetry
Sexual Dimorphism: female larger
Great white sharks are apex predators; they are at the top of the food chain. Occasionally great white sharks will encounter a killer whale or another shark of comparable size (Martins and Knickle, 2009). These species pose a small threat to great white sharks.
Much about the mating behavior of great white sharks is still unknown. Some scientists believe that scarred individuals suggest male-male aggression or that a male’s gentle biting of females may precede mating. Bite marks observed on the dorsum, flanks, and particularly the pectoral fins of mature female great whites have been interpreted as the results of mating. It is most likely that the male bites the female during copulation. Great white sharks have also been known to propel two-thirds of their body out of the water and land flat against the surface, causing a large splash. This behavior is called a "pattern breach". This behavior might be used to attract a mate during courtship. Mating has yet to be fully documented in great white sharks, but it is assumed to be similar to internal fertilization in most sharks, where the male inserts his claspers into the cloaca of the female. Courtship behavior, if there is any, is unknown.
Mating System: polygynandrous (promiscuous)
Reproduction is ovoviviparous, that is, fertilized eggs are retained within the body and develop there. Prior to birth, the young in the womb may feed on undeveloped eggs and possibly their unborn siblings. Litters consist of 2 to 10 pups. Newborns are more than 1 meter (about 3 feet) in length. Gestation is thought to take about 12 months, and females are assumed to give birth in warm temperate and subtropical waters, but specific nursery areas are unknown. Females give birth to live young, unlike many other sharks who lay eggs. It is possible that individual females only reproduce biannually, mating soon after giving birth, but this remains to be confirmed. Male great white sharks reach sexual maturity at 3.5 to 4 meters (about 11.5 to 13 feet) in length and about 10 years of age, whereas females reach sexual maturity at 4.5 to 5 meters (about 15 to 16 feet) in length and 12 to 18 years of age.
Breeding interval: Female sharks may breed every two years.
Breeding season: The breeding season is unknown.
Range number of offspring: 2 to 14.
Average number of offspring: 7.
Average gestation period: 14 months.
Range age at sexual or reproductive maturity (female): 14 to 16 years.
Range age at sexual or reproductive maturity (male): 9 to 10 years.
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); ovoviviparous
Newborns get no help from their mothers after birth. As soon as they are born they swim away and are independent. A newborn is about 1.2 m long and grows 25 cm each year, reaching maturity at 10 years (Dale, 2008). Offspring are capable predators the moment they are born.
Parental Investment: no parental involvement; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female)
