Biggest Shark
The biggest shark in the world is the whale shark. It lives in warm and tropical waters of the Atlantic, Pacific and Indian Oceans. Although it is the biggest shark, humans have nothing to fear from the whale shark as it primarily feeds on plankton. It is thought to grow to reach 20 meters long or 65.6 feet. The sharks may be half of their full adult size before they become sexually active. There is still much to learn about this shark, including how long it lives. Its lifespan is estimated to be approximately sixty years.
The upper body of a whale shark can be shades of blue, gray or brown with patterns consisting of stripes and spots that resemble a checkerboard. The stomach is white. The biggest shark has a very flat head that looks broad and recessed into a quite sleek-looking body. Its mouth is very large. A whale shark has two dorsal fins, with the front one much larger than the rear. The reason for a whale shark’s distinctive color pattern is not known--there is speculation that it is camouflage for protection or that it serves a purpose in attracting a mate.
A whale shark has three-hundred teeth in each jaw, but they are very small and not thought to be used at all in eating. In fact, the whale shark has an elaborate filtering system. It eats by opening its mouth and sucking in plankton and water. When the shark closes its mouth, the water is released back out through the gills. Denticles in the gills act like a sieve and catch anything larger than two or three millimeters (just over an inch), keeping it inside while the water is released. This suction system is unlike that of other sharks and can be described as similar to a vacuum cleaner moving through water. Plankton is the whale shark’s primary food but it also will eat meat in the form of schools of fish, crustaceans, squid or tuna.
Whale sharks are ovoviviparous, meaning that they reproduce by producing eggs but the eggs remain in the female’s body until they hatch. They are then delivered by live birth. This fact about the biggest whale was not discovered until 1995, when a pregnant female whale was harpooned near Taiwan. She was carrying three hundred babies that ranged in size from sixteen to twenty-two inches. The egg capsules from which the young sharks emerged were amber in color had a respiratory opening.
Every year approximately one hundred whale sharks are killed in Taiwan, mainly for their meat, which can sell at very high prices. They are also killed for meat in the Philippines. Whale sharks are sometimes caught in India, where oil from their livers is used for everything from waterproofing wood to shoe polish or for medicinal purposes. Shark fins are often sold in places like Hong Kong and command a very high price.
Overall, not much attention has been paid to whale sharks, but they are listed as vulnerable or threatened on the lists of several conservation organizations. In the Gulf of California, whale sharks do not have an “at risk” classification. There is some fear that as the world’s population increases, the world’s biggest shark might be killed more and more often to supply food for human consumption, especially areas of the world where people live in poverty.