About the World's Largest Sharks

They are the menacing creatures of the deep blue sea that instill fear in those brave enough to venture into murky ocean waters, especially after the release of Steven Spielberg's "Jaws." Despite their reputation for being vicious killers, the world's largest sharks, at least the two largest, are actually gentle giants of the sea. The third, however, has a fierce reputation, but is more likely to taste test you than actually kill you.

Type

Now extinct, the megalodon was the largest shark to ever exist. This ancient dominant marine predator roamed the ocean over 2 million years ago and grew up to 60 feet. The megalodon’s teeth were the size of a human hand enabling it to be a fierce predator of the deep.

Today, the largest shark in the world, the whale shark, only grows between 40 to 50 feet and is generally considered harmless to humans since it prefers feeding on phytoplankton, macro-algae, krill and small nektonic life over flesh.

Like the whale shark, the basking shark, the second largest shark, is a passive filter feeder that poses no direct threat to humans or larger marine life. The basking shark grows to about 40 feet long.

On the other side of the spectrum, the third largest shark in the world, the great white shark, made infamous by the movie "Jaws," prefers the fleshy taste of meat. This carnivorous shark grows up to 21 feet in length and is the shark most feared by humans.

Features

Flat wide heads with eyes located towards the front of the head characterize the immensely large whale shark whose mouth measures a whooping 5 feet wide. While the mouth can contain up to 350 rows of teeth, this passive shark feasts upon smaller marine animals. A whale sharks is mostly gray with a white patch on the belly and has three prominent ridges running along the side of its body.

Second in size, the basking shark, sometimes mistaken for the great white, has dark brown/black to blue coloration that fades to a dull white vertically. With a cavernous 3-foot-wide mouth, the basking shark has longer and more obvious gill slits, but smaller eyes than other sharks.

The feared great white shark, blue-gray to white in color, has specialized sensory organs called lamellae which detect odors, turning the shark into a swimming nose. With extremely acute and sensitive smell, a coloration made to camouflage, several rows of razor sharp teeth, and a large powerful body with a specially designed energy-bursting tail, the great white shark is a natural hunter.

Geography

Generally remaining offshore, the whale shark frequents tropical and warm-temperate oceans around locations like Belize, Western Australia, Madagascar, Honduras and the Philippines, but they find their safe zone in the Bay of La Pez. Basking sharks prefer any of the world’s temperate oceans from boreal to warm temperature waters, especially those located around continental shelves. Great whites predominantly reside off the coasts of Australia, South Africa and Guadalupe Island.

Risk Factors

While most sharks pose a potential threat to humans, whale sharks and basking sharks are more likely to playfully nudge a diver than take a bite of him. Unless provoked, both whale sharks and basking sharks are generally harmless.

Depicted as a "man-eater," great white sharks have an infamous reputation of mistakenly targeting humans for prey, especially surfers. Biologist Douglas Long contends that the great whites "role as a menace is exaggerated; more people are killed in the United States each year by dogs than have been killed by great whites in the last 100 years." While this statistic may prove true, taken into context, humans have far more interactions on a daily basis with canines than great whites, which may be a contributing factor to this statistic. However, less people die from great white attacks than it seems. Over the last two centuries, there were only 31 confirmed attacks by great whites in the Mediterranean Sea. Shark researchers believe there are not more human fatalities simply because of how a great white attacks. Great whites inflict a lethal bite to the head or trunk of its victim only to then swim away while the victim bleeds to death; and, with humans, this hunting technique provides escape room. Some researchers believe this hunting method decreases the amount of human fatalities. On the other hand, other shark experts theorize that great whites simply "test bite" humans in the same way they "test bite" other unfamiliar objects like buoys.

Expert Insight

Despite a bad reputation and prevalence for human attacks, sharks play an important role in the marine ecosystem. Great white sharks, for instance, eliminate the weak and sick and keep the seal and sea lion populations balanced. Due to overfishing, the great white shark population has plunged into near extinction, which has allowed for an increase in sea lion and seal populations, thereby resulting in a decline in the salmon population.

Basking sharks, a staple to fisheries with their slow swimming speed and non-aggressive nature, are on the verge of extinction. Exploited for centuries to supply the worldwide market demand, basking sharks were killed exclusively for their fins, flesh and organs to provide a vitamin A supplement, lubricant for machinery, tanning leather and lamp oil. Even the whale shark population has plunged by 40 percent over the past decade.

Humans have hunted sharks for sport, medicine, food and leather for centuries, with little regard for the health of shark populations. As a result, some shark species are on the verge of extinction, like the great white and basking, and this rapid decline in shark population is severely disrupting the fragile marine ecosystem. All three of the world’s largest sharks face extinction at the hands of humans, despite the whale shark's and basking shark's passive natures.