Interesting Facts About The Great White Shark
The great white shark is the largest predatory fish in the ocean. Its name refers to both the animal's size and the color of its belly. The upper side of the shark is not actually white but a bluish-gray, brown or black color that blends in with the rocky ocean floor when viewed from above.
The great white can grow up to 20 feet long, although most are smaller. The record-holding shark was caught in 1993 off the coast of Prince Edward Island. The average adult is 15 feet long and weighs 1,150 to 1,700 pounds.
Great whites have hundreds of teeth in rows in their mouth. As the front teeth fall out, the ones in the rows behind move forward to replace them. The teeth of a great white are serrated and extremely sharp. Once they have bitten down on a prey animal, the shark will sometimes shake its head to increase the tearing action of its bite.
The great white is one of the fastest fish in the sea. It has a torpedo-shaped body and a strong tail fin that allows it to move up to 15 miles per hour. Great whites are also known to leap out of the water after their prey.
The liver of a great white shark can make up as much as 24 percent of its body weight. This can amount to 500 pounds or more. The liver is used to store energy in these animals, which enables them to go long periods of time without eating.
Great white sharks live all across the world. They can be found off the coast of every continent except Antarctica. There are at least two major populations that do not appear to mix, consisting of the sharks that live off of South Africa and Australia, and those that live in the North Pacific.
Great whites spend most of their time in temperate, coastal waters that range from 54 to 75 degrees F. They do make brief forays into both colder and warmer waters, though. Adult male sharks seem especially likely to range far afield, but both sexes can and will travel hundreds or even thousands of miles.
The majority of the great white's diet is made up of seals and sea lions. Adults eat almost exclusively marine mammals, including small whales and dolphins in addition to seals and sea lions. Younger sharks eat rays, smaller sharks and various fish.
A big shark can swallow a sea lion whole. It takes approximately 11 tons to feed an adult great white shark for a year. However, a big shark may only need one large meal every three months.
The adult great white has few natural predators. Orcas can and will eat great whites on occasion and other, larger sharks can be a hazard as well. Humans are a major cause of mortality in adult sharks, too, though accidental or intentional fishing catches.
Reproduction and Growth
The mating practices of Great White sharks are still largely unknown. There appear to be areas that the adults gather during the breeding season to mate but mating has never been observed. It is thought that females have a litter about every two years, but even this is unsubstantiated.
Female great white sharks carry their young internally. The gestation period is approximately 18 months. Once the young sharks, known as "pups," have hatched, they are fed on unfertilized eggs until they are born.
Litters consist of four to fourteen pups that are born at approximately 5 feet in length. Young great whites seem to be born in nursery areas where the water is warmer. They stay in these warmer waters until they are big enough to maintain their internal body temperature in colder climates.
It takes at least 9 years for a male great white to reach sexual maturity. Females take as long as 16 years. The average lifespan of the great white shark is only 25 years, which gives females time for only four or five litters in their life.
Great White Sharks and Humans
Humans are not on the menu for great whites, but this doesn't keep a few "accidental" bites from occurring each year. One thought is that the human silhouette looks like a seal to the shark. Another thought is that these big fish are curious, and occasionally investigate humans by taking a test bite. Although this doesn't exactly sound reassuring, most shark bites are not fatal.