The largest known great white sharks are 20-35 feet long. The adult female is usually bigger than the male and averages 15 feet in length. The adult male averages 11 feet in length. A great white shark never stops growing, so every year it gets a little longer and a little bigger. Sharks, like all other fish, are cold-blooded.

They weigh up to 9,500 pounds. They are not as large as the whale shark, which is the largest and longest shark. Great white shark's hearts are very large and weigh up to 10 pounds. But their brains are very small and are only about three inches long.

Great white sharks feel little pain compared with humans. Even when they are badly hurt, they do not feel the pain.

Great white sharks have a good sense of smell. Their nostrils are used for smelling only, not for breathing. The have gills for breathing. Most great white sharks have five very long gill slits. They do not have gill covers like other fish. As the sharks swim, water goes into their mouths, over their gills, and out their gill slits. This movement of water allows the great white sharks to breath oxygen from the water.

Great white sharks have cone-shaped snouts and medium sized black eyes that are good at seeing in both day and night. They also have two lobes of the same size that makes up their tail. They also have pectoral fins with black tips. These are two good way to identity great white sharks.

What are the teeth of great white sharks like?

Great white sharks have two rows of teeth. If they lose a tooth, the tooth will grow back soon because they have extra teeth in their gums. Their teeth are similar to prehistoric animals' teeth.

The teeth and jaws of great white sharks are of great value and people from all over the world try to find or purchase them. They are often made into bracelets, necklaces, and earrings. Years ago, Indians in Florida used their teeth as arrowheads.

The teeth of the great white shark are triangular and are notched like a saw. This makes them doubly sharp. These razor sharp teeth are up to three inches long. Great white shark have powerful jaws with the lower jaw being skinnier than the upper jaw. Check out these teeth.

What kinds of foods do great white sharks eat?

All great white sharks are carnivorous, which means flesh eating. Of all the fish, sharks are the best designed to hunt and kill their prey. However, fishermen are destroying much of the sharks' food sources.

Great white sharks eat gray sharks, tiger sharks, marlins, tunas, penguins, seals, sea lions, turtles, whales, porpoises, and many other fish. They can swallow an adult human whole. Two whole sea lions were found inside the body of a 16 foot great white shark. Great white sharks taste anything they think is edible. Many sharks have been found with tin cans, bicycle parts, tar paper, nails, and other unusual things in theri stomachs. Some great white sharks have even been found with horses or elephants in their stomachs.

Great white sharks use their eyes to find food. They can also sense the movement of other fish up to 800 feet away, using their ears and their distance touch. But they usually use their sense of smell to find food.

Great white sharks hunt the weak, the old, the young, and the crippled. When they small blood in the water, they go into a feeding frenzy and attack anything in sight, including other great white sharks. They often tear out fifteen pound chunks of their preys' flesh, and swallow them whole. The steps in attacking and feeding on prey are:

• they smell blood
• they swim toward the blood like a guided missile (Freedman, 1985)
• they circle their prey, moving quickly and without warning
• they do not bump or nudge their prey like other sharks
• they bite their prey
• they shake their heads and thrash, tearing flesh away from their prey
• they swallow their bite whole

How do great white sharks move in the water?
How do their fins help them swim?

Great white sharks swim very fast compared to other sharks. However, they swim slower than bony fish. Their usual swimming speed is 25 miles per hour.

Their minimum swimming speed is three to five miles per hour. They use this speed when looking for prey. When they sense food nearby, they speed up and swim as fast as 40 miles per hour. Their main swimming power comes from their tails. They can swim as fast under water as they swim on the surface. But they can't swim backwards.

Great white sharks must keep swimming at all times or they will die. They do not have a swimm bladder like other fish and will sink to the bottom if they stop swimming. They will rest, but never sleep like humans do.

Fins help great white sharks keep balanced whern they swim. They are also used for steering. Great white sharks are not able to turn quickly.

Where do great white sharks live?
Do they migrate?

Great white sharks usually live in warm water. They like to live south of the equator, but they are also found north of the equator. Many are found off the coast of California where they eat sea lions. They swim near the top of the sea looking for their prey.

Although many people think great white sharks like beachers and attacking humans, it is usually rare to see them swimming in shallow water. There are about 30 known great white shark attacks each year, but usually they leave humans alone.

The great white sharks that live in New England migrate south along the east coast of the United States to the Gulf of Mexico or the south Atlantic Ocean.

What are the friends and enemies of great white sharks?
How do they defend themselves?

The two fish that think of great white sharks as their friends are the remora fish and pilot fish. The remora fish uses its suckers to connect itself to the shark and get a free ride on the shark's body.

The pilot fish swims near the shark and is carried along by the movement of the water. Both fish eat the small bits of food left by the great white shark.

Great white sharks are cannibals. They fear nothing. Their only enemies are bigger great white sharks and man, who fishes for sharks all over the world. They use their teeth, their jaws, their speed, and sometimes their tails to defend themselves. In 1959 a fisherman caught a 2664 pound shark with a seal's liver as bait. Fishing companies catch thousands of shark each year.

Great white sharks do eat dolphins, but dolphins never eat great white sharks. Dolphins will attack and kill sharks so the sharks won't kill young dolphins, but dolphins will never eat the dead shark. When a mother dolphin was giving birth in a large aquarium, male dolphins in the school bumped, poked, and bashed the shark until the shark died.

How do scientists study great white sharks?

Scientists have metal cages that sharks usually cannot break open. White sharks often attack cages, bending the bars, tossing the cage around, and sometimes shattering them. But scientists also wear iron suits that protect them. These suits weight 12 - 16 pounds and are somewhat like the suits that knights wore in the Middle Ages.

Great white sharks are the most feared of all fish. Divers treat them with respect because they are unpredictabler. Scientists have found that they should not swim with an open wound, or great white sharks will smell the blood and hunt them down. When scientists find a dead shark, they freeze it and ship it to a lab for more study.

Scientists have tried to keep great white sharks in captivity so they can study them. But they have not been successful in keepingh great white sharks alive in captivity. One eight and a half foot shark lived only 35 hours in an aquarium at Marineland, Florida. Another four and a half foot great white shark lived only five days in Seaworld in California.

Great white sharks are seldom seen in groups of more than two. These sharks are hard to study because they are hard to find and not easy to keep up with. But, scientists think someday their study of sharks will help them cure human cancers. Sharks don't seem to have cancer like other fish and humans, so scientists hop sharks' cartilage and liver may help doctors cure cancer. In Japan, doctors use juices from sharks' livers to cure many diseases.

Little is known about whether great white sharks can communicate with other fish and dolphins. This is a mystery scientists are still trying to solve.

Credits:

Freedman, Russell. (1985). Sharks. New York:Holiday House.

Sattler, Helen. (1986). Sharks, the Super Fish. New York: Lothrop, Lee & Shepard.

Pictures from Shark.com, ExtremeScience, DiveAtlas.com,

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