Great white shark

Great white shark

Great white shark

The great white shark, Carcharodon carcharias, is one of the largest predatory fish in the world. Adults reach lengths of up to 20 feet (6 m), though most are smaller than 15 feet (5 m). They grow very slowly, taking about 30 years to reach maturity. Females mature slightly earlier than males. Their lifespan ranges from 60 to 80 years.

The great white shark is found worldwide in temperate, subtropical, and tropical waters. In the Atlantic Ocean it inhabits coastal regions from southern Canada southward along the east coast of North America to Brazil, including Bermuda and the Gulf of Mexico; in the Pacific Ocean it occurs from Japan to Chile. This species is known to migrate long distances seasonally, and individuals have been recorded migrating over thousands of kilometers.

Size and distribution

Over the past century, the average length of great whites measured off South Africa increased from approximately 10 meters to 14.7 meters (37 ft 0 in to 47 ft 4 in); however, there is some evidence that this trend might have reversed recently. Off New Zealand, mean sizes ranged from 12.1 to 13.2 metres (39 ft 9 in to 43 ft 8 in) from 1876 to 2001. A study published in 2010 reported an increase in size of 2.3% per decade since 1960, although others dispute this finding.

In Australia, the mean length of great whites caught in commercial fisheries has steadily increased from around 11.8 metres (38 ft 5 in) in 1950 to around 16.0 metres (51 ft 3 in) in 2004. However, this trend appears to have leveled off in recent years.

A survey conducted in the 1990s suggested that great white sharks could live to 50 years old or older. More recent studies suggest that maximum longevity is closer to 40 years, though the oldest confirmed individual lived to 72 years.

Reproduction of Great white shark

Great white sharks are viviparous: they give birth to litters of 1–10 pups every two years. Pregnancy lasts for 6 months, during which time the female gives birth to a single pup at intervals of 2–4 weeks. Gestation takes place between July and December, with births occurring between October and January. Litters typically consist of 7–9 pups, but may be as few as 5 or as many as 12. Litter size varies by location and year. For example, females born in the Southern Hemisphere tend to produce larger litters than those born in the Northern Hemisphere.

Off South Africa, the gestation period averages 6.5 months, ranging from 5.5 to 7.5 months, while the interval between births averaged 2.5 months, ranging between 2.0 and 3.0 months. Births occur throughout the year, but peak in late summer and early autumn. Off Western Australia, the gestation period was estimated to be 6.2 months, and the inter-birth interval was estimated to be 2.4 months.

Off California, the gestation period was calculated to be 6.0 months, and the interbirth interval was estimated to range from 2.5 to 3.0 months. Off Cape Cod, Massachusetts, the gestation period was 6.0 months, while the inter-birth interval averaged 2.5 months. Off the west coast of Ireland, the gestation period was 5.5 months, and the interpupal interval averaged 2.5 to 3 months. Off the west coasts of Scotland and England, the gestation period was also 5.5 months, while inter-birth intervals were estimated to be 2.5 to 3 years. Off the west coast and north of Spain, the gestation period was about 6 months, and the interlitter interval was about 2.5 months.

Classification

The great white shark is the sole recognized extant member of the genus Carcharocles, and it is one of five extant members of the family Lamnidae, along with the blacktip reef shark, blue shark, sandbar shark, and smoothhound shark. These sharks are characterized by having broad pectoral fins, long bodies, large heads, and small mouths. They range in size from about 4 feet (1.2 m) to over 20 feet (6 m). Their coloration varies greatly depending on age, sex, diet, geographic location, and season. Juveniles tend to be dark grayish brown or light brown, while adults are usually lighter in color. Some individuals exhibit a pale band running down their sides, and some have spots or stripes. Adults typically grow longer than 9 ft (3 m), although specimens up to 18 ft (5.4 m) have been recorded. Females mature faster than males, reaching sexual maturity around 10–12 years old; however, males reach full adulthood at 14–16 years old. The lifespan of the great white ranges from 30 to 50+ years, though most do not live beyond 40 years.

Etymology and naming history

“White shark” and “white pointer” are common names used for the great white shark. These terms originated from the shark’s distinctive appearance, particularly its white belly. In many parts of Australia, where the white pointer is found, this same area is known locally as the “shark bite zone.” This name is believed to have originated from the shark’s habit of biting off chunks of flesh from humans who venture too close to the shoreline.

In addition to being called “the white shark,” the great white is sometimes referred to as “Carcharodon carcharias” — the Latinized version of the Ancient Greek term karkharios (“jagged”). This term is commonly shortened to just “carcharodon” among scientists.

Fossil ancestry

– A study published in Nature Communications suggests that the evolution of the great white shark began with a group of sharks called the evolution of the great white shark began with a group the megatooth shark family, which consisted of three genera.

– The first genus ,which included the most recent ancestor of the great white shark, was Megalolamna. Megalolamna had a tooth shape similar to those found today in the great white shark. However, the teeth of the ancestors of the great white shark were much larger than those of the megatooth sharks.

– The second genus, which included the earliest ancestor of the great white, had a tooth shape similar to that of the ancestor of the great white. However, the teeth were smaller than those of the megatalamiens.

– The third genus, which includes the oldest ancestor of the great white sharks, was Carcharodus.Carcharodus had a tooth shape similar those found today in the great white shark. However,the teeth were smaller than those of the megatalamiens. A phylogenetic tree constructed from the fossil evidence suggested that the great white shark diverged from the ancestor of the megatalamienses about 50 million years ago.

– In addition, the researchers discovered a fossilized tooth belonging to an intermediate form that could represent a missing link between the Carcharodus and the great white shark.

– The researchers believe that the transition from a tooth shape resembling that of the ancestor of Carcharodus to one like that of the great white shark occurred gradually.

– They suggest that the ancestral form of the great white shark resembled that of the Carcharodus, and that the teeth became progressively longer and sharper during the course of its evolution.

Distribution and habitat

The distribution of the great white shark includes most of the world’s oceans except Antarctica. Its range extends from the temperate regions of the North Atlantic Ocean and Pacific Ocean to tropical latitudes of the Indian Ocean and western boundary current system. This species occurs in every major ocean basin except the Arctic Ocean and Antarctic Ocean.

Habitat preferences are variable, ranging from nearshore habitats close to continental shelves to pelagic habitats far offshore. Most great white sharks occur near shoreline areas where there is abundant prey availability, particularly during winter months.

Great whites prefer shallow inshore waters along coastlines and adjacent estuaries. They often move into deeper offshore waters during summer months, especially during the day.

In the North Atlantic Ocean, the greatest concentration of great whites appears to occur off southern New England, although some individuals may migrate northward during winter. Off Cape Cod, Massachusetts, the population density is highest; however, this region represents less than 10% of the total North Atlantic population.

In the Northeast Pacific Ocean, the largest aggregation of great whites occurs off central California, where several hundred individuals have been documented over the past three decades. A smaller number of animals are present off Oregon and Washington state, while few great whites are reported from Alaska.

In the Northwest Pacific Ocean, the greatest abundance of great whites occurs off southern China, Taiwan, Korea, and Japan. Lesser numbers are reported from the Yellow Sea, East China Sea, Bohai Gulf, and South China Sea.

In the Southwest Pacific Ocean, the greatest concentration appears to occur off southeastern Australia, where many hundreds of great whites have been sighted since the early 1980s. Smaller aggregations are reported off Western Australia, Tasmania, and Lord Howe Island.

Anatomy and appearance

The great white shark (Carcharodon carcharias) is the largest predatory fish in the world. It grows to about 20 feet long and weighs over 2,000 pounds. Great whites are known to travel in groups called “pods,” each consisting of several individuals. They hunt mainly in coastal areas near shorelines where there is plenty of food. In addition to eating marine mammals such as seals, sea lions, penguins, and dolphins, great whites also eat smaller sharks, rays, turtles, and even whales.

Great white sharks are often mistaken for killer whales due to their shape and behavior. However, unlike orcas, they do not kill humans. Although attacks on people are very uncommon, they occasionally bite swimmers while feeding.

Size

Great white shark size varies depending on where you live. In Australia, Great Whites tend to be smaller, measuring around 10 feet (3 meters) long. But in South Africa, Great Whites reach up to 18 feet (5.5 meters), making it one of the largest species of shark found anywhere.

The female Great White shark is usually bigger than the male. On average, mature females weigh about 1,150 pounds (544 kilograms), while males typically weigh about 750 pounds (340 kilograms). However, some mature females can weigh as much as 1,500 pounds (680 kilograms).

The great white shark (Carcharodon carcharias), commonly known as “white pointer”, “white devil”, “great white” or “shark”, is a large predatory fish belonging to the family Lamnidae within the suborder Selachimorpha. Great whites are apex predators in the open ocean, preying mainly upon marine mammals such as seals, sea lions, dolphins and porpoises, and occasionally smaller fishes and crustaceans. They are found worldwide in temperate and tropical oceans where there is sufficient food supply. Although usually solitary, adult males form loose groups called breeding aggregations during mating season. Females give birth to one pup every three to five years.

Great whites reach maturity at about seven years old and live up to 50 years in captivity. Males mature sexually at around 10 years old, and females at around 12 years old. Female great whites grow faster than male individuals, reaching sexual maturity at a younger age. However, the growth rates of both sexes decline steadily over time. Great whites have slow reproductive cycles compared to most other sharks. This makes it difficult to determine the exact lifespan of great whites in the wild because individuals do not reproduce continuously throughout their lives.

Hunting and diet

The white shark is one of the most feared predatory fish in the world. A highly adaptable predator, it has a mouth lined with hundreds of sharp, serrated teeth arranged in several rows. Its eyesight is excellent, and it has a keen sense of smell that enables it to track down food. White sharks feed primarily on large marine mammals such as seals, sea lions, and sea otters; however, they will eat anything else that fits into their jaws. At times, they even attack humans.

White sharks are known to hunt other sharks, including great whites, tiger sharks, bull sharks, hammerheads, blacktips, and lemon sharks. However, they rarely target smaller sharks because they lack the strength to subdue them. Instead, they prefer larger marine mammals, especially sea lion pups. In fact, some researchers believe that white sharks are actually hunting sea lions to help themselves grow faster.

A white shark will follow a seal or sea lion across open water for miles, waiting patiently for the opportunity to strike. Once it has found a suitable meal, it will swim toward the animal and clamp onto its body with its razor-sharp teeth. When the shark bites, it uses its powerful jaw muscles to tear off chunks of flesh. Although the bite itself does little harm, the force of the bite can cause internal injuries. As the shark feeds, it swallows the blood and tissue that flows out of the wound. This helps keep the wound clean and prevents infection.

Once the shark has finished eating, it usually leaves the carcass behind and continues swimming away. If the shark feels threatened, it will often emit a loud noise called a “strange call.” This sound originates in the larynx, located near the throat, and travels through air sacs in the head. These sounds are produced by rapidly vibrating vocal folds in the larynx. The frequency of the sound varies depending on the size of the shark. Smaller sharks produce lower frequencies while larger sharks make higher ones.

As a defense mechanism, white sharks can generate electric shocks along their bodies. Researchers speculate that this ability evolved as a way to deter potential attackers. However, it doesn’t seem to work very well against humans.

Shark attacks

Of the 100-plus annual reports of shark attacks worldwide, anywhere from one-third to half are attributed to great whites. But most of these are not fatal. In fact, according to research published recently in the journal PLOS ONE, most of these attacks are not even very serious.

The study found that while there have been about 300 fatalities since 1900, most of those deaths occurred before 1950. And even though many people die each year from shark bites, the majority of those victims could have survived had they sought medical attention earlier.

In addition, the researchers discovered that the number of lethal shark attacks has remained relatively stable over the past century. This suggests that the threat posed by great whites has not increased, despite growing populations of humans and seals along coastal areas.

So what explains the uptick in fatal shark attacks? Researchers don’t know for sure, but they suspect that some recent attacks might have involved a different species. For example, a few fatal incidents have been linked to tiger sharks, which tend to hunt in groups.Of the 100-plus annual reports of shark attacks worldwide, anywhere from one-third to half are attributed to great whites. But most of these are not fatal. In fact, according to research published recently in the journal PLOS ONE, most of these attacks are not even very serious.

The study found that while there have been about 300 fatalities since 1900, most of those deaths occurred before 1950. And even though many people die each year from shark bites, the majority of those victims could have survived had they sought medical attention earlier.

In addition, the researchers discovered that the number of lethal shark attacks has remained relatively stable over the past century. This suggests that the threat posed by great whites has not increased, despite growing populations of humans and seals along coastal areas.

So what explains the uptick in fatal shark attacks? Researchers don’t know for sure, but they suspect that some recent attacks might have involved a different species. For example, a few fatal incidents have been linked to tiger sharks, which tend to hunt in groups.

Population and conservation

There is no reliable population data on the great white shark, though experts agree that it is declining precipitously. Overfishing and getting caught in fishing nets are the two biggest threats to the species. They are classified as vulnerable—one level away from being considered endangered—by the International Union for the Conservation of Nature (IUCN).

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