Great White Shark

By Justin Affleck

Animal Species• The great white shark,

Carcharodon carcharias, also known as great white, white pointer, white shark, or white death, is an exceptionally large lamniform shark found in coastal surface waters in all major oceans.

Appearance• The great white shark has a robust large conical-

shaped snout. It has almost the same size upper and lower lobes on the tail fin.

• Great white sharks have a white underside and a grey dorsal area. These colours makes it difficult for prey to spot the shark. When viewed from above, the darker shade blends in with the sea and when seen from below it casts a minimal silhouette against the sunlight.

Teeth• Great white sharks have rows of teeth behind the

main ones, allowing any that break off to be rapidly replaced.

• A great white shark's teeth are serrated and when the shark bites it will shake its head side to side and the teeth will act as a saw and tear off large chunks of flesh.

• Great whites often swallow their own broken off teeth along with chunks of their prey's flesh.

• These teeth frequently cause damage to the great white's digestive tract, often resulting in death from infection and blood loss.

Size• A typical adult great white shark measures

4–4.8 metres and has a mass of 680–1,100 kilograms, females generally being larger than males. The great white shark's average size is about 6 m, with a average weight of about 1,900 kg.

• Although there was a 11 m great white captured in Southern Australian waters near Port Fairy in the 1870s, and a 11.3 m trapped in a herring weir in New Brunswick, Canada in the 1930s.

Diet• Great white sharks are carnivorous, and primarily

eat fish, rays, tuna, and smaller sharks, dolphins, porpoises, whale carcasses and pinnipeds such as seals, fur seals and sea lions and sometimes sea turtles.

• Sea otters and penguins are attacked at times although rarely, if ever, eaten.

• Great whites have also been known to eat objects that they are unable to digest.

• In great white sharks above 3.41 metres a diet consisting of a higher proportion of mammals has been observed.

Where it lives/Habitat• Coastal and offshore waters.

• Great white sharks live in almost all coastal and offshore waters which have a water temperature of between 12 °C and 24 °C , with greater concentrations off the southern coasts of Australia, off South Africa, California, Mexico's Isla Guadalupe and to a degree in the Central Mediterranean, Adriatic Seas and New Zealand, where they are a protected species.

• One of the densest known populations is found around Dyer Island, South Africa where much research on the shark is conducted.

• It can be also sometimes found in tropical waters like those of the Caribbean, and has been recorded off Mauritius, Madagascar, Kenya and the Seychelles.

Adaption's• To more successfully hunt fast moving and agile prey such

as sea lions, the great white shark has developed adaptations that allow it to maintain a body temperature warmer than the surrounding water.

• One of these adaptations is a "rete mirabile". 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 blood that has been warmed by the working muscles.

• This keeps parts like the brain at temperatures up to 14 °C above the surrounding water, while the heart and gills remain at sea-temperature.

• When conserving energy a great white shark can go weeks between meals.

Why does it migrate?• Traditional theories of white sharks being

coastal territorial predators has been disproved and opens up the possibility of interaction between white shark populations that were previously thought to be discrete from one another.

• It is still unknown why they migrate and what they do at their destination.

• It might be seasonal feeding or possibly a mating area.

When does it migrate?Where?

• In a recent study, great white sharks from California were shown to migrate to an area between Baja California and Hawaii known as White Shark Café, where they spend at least 100 days of the year before they migrate back to Baja.

• On the journey out, they swim slowly and dive down to around 900 m. After they arrive, they change behaviour and do short dives to about 300 m for up to 10 minutes.

• Another white shark tagged off the coast of South Africa swam to the southern coast of Australia and back within the space of a year.

How does it migrate?

• It swims.