Eric Brown, age 7, of Hutchinson, Kan., for his question:
HOW LARGE CAN A SHARK GROW?
One of the most feared animals of the sea is the shark. There are about 250 different kinds in all of the world's oceans. Most of the fish, however, are found in warm seas.
Largest shark of all is the whale shark who may grow to be 60 feet long. A whale shark may weigh up to 15 tons, which is more than twice as much as an African elephant. This shark is the largest of all fish.
The world's smallest shark measures only four inches long and weighs less than one ounce.
All sharks are carnivores, which means that they are meat eaters. Most of them eat live fish, including other sharks. A shark will eat his prey whole or tear off chunks of flesh.
A shark's only natural enemy is a larger shark.
Sharks have the reputation of being man eaters, but fewer than 100 shark attacks each year are reported throughout the entire world. about 25 species, of the 250 found in the oceans of the world, have been know to attack human beings.
Some sharks live in the deepest parts of the ocean while others are found near the surface. Some select the coastal waters while others choose to live far out at sea. A few kinds can even live in fresh water.
Sharks can travel with great bursts of speed. The blue shark has been clocked at speeds of 43 miles per hour.
Most sharks have a crescent shaped tail that gives them power for swimming. The upper part of the tail is longer than the lower part. Stiff pectoral fins on the sharks' side help lift and balance the front of the body.
Most fish have swim bladders. These are gas filled organs that help them remain at certain depths without sinking. Sharks do not have this organ. Instead, they have large livers filled with oil. This oil is lighter than water and it helps keep the shark from sinking.
Sharks have no bones. Their skeletons are made of a tough, elastic substance called cartilage.
The body of a newborn shark resembles that of an adult in almost every way except size. Sharks have fewer young at a time than most fish do. Some species give birth to 50 or 60 babies in a litter, but most have far fewer.
The parents of baby sharks do not take care of the young. In fact, many parents eat the babies that are not swift enough to escape.
Shark eggs, unlike those of most fish, are fertilized inside the female's body. The male shark has two organs called claspers, which release sperm into the female, where it fertilizes the eggs.
Among most species of sharks, the eggs hatch inside the female, and the babies are born live. A few species lay their eggs.
A shark's mouth is on the underside of the head among all species except whale sharks. The mouth of the whale shark is at the front of the head.