Vickie Young, age 10, of Birmingham, Ala., for her question:
WHERE DO DOLPHINS LIVE?
Dolphins are small, whalelike mammals whose snouts form beaks. They are swift and graceful swimmers that can be found in all the oceans of the world and in some rivers.
The two most common kinds of dolphins are the bottle nosed dolphins and the common dolphins.
The common dolphin is found in warm ocean waters. It grows to be about seven feet long and weighs up to about 150 pounds. Its beak is about six inches long and it has from 80 to 100 teeth.
Large shcools of common dolphins often leap around ships in apparent joy. For hundreds of years, many seamen have regarded these dolphins as a sign that their voyage will be smooth and happy. For this reason, sailors frequently refused to kill the dolphin, even though its meat is delicious.
The common dolphin has a black back and a white underside, and prominent gray and brown stripes on its sides.
The bottle nosed dolphin is the star performer that you often see in aquariums and zoos. This dolphin can be trained to leap high into the air to grab a fish from its keeper's hand. It can also be taught to jump through a hoop and to fetch a thrown ball.
The bottle nosed dolphin is found in coastal waters. It grows to be 12 feet long and can weigh as much as 800 pounds. Its beak is about three inches long and it has from 80 to 88 teeth. This dolphin is grayish in color and its back is darker than its underside.
Scientists consider the bottle nosed dolphin to be one of the most intelligent animals on earth. Some say its intelligence ranks between that of the chimpanzee and the dog.
The dolphins are often confused with the porpoises, which do not have beaks.
Dolphins communicate with one another by making sounds that include barks, clicks and whistles. Bottle nosed dolphins can even imitate some sounds of human speech.
A dolphin produces sounds by blowing air through the air passages it used for breathing. These passages lead to the blowhole, an opening at the top of the dolphin's head. The air passages and the blowhole have flaps of muscle that move to help make different sounds.
Because of the dolphin's high intelligence, some persons have believed that man could learn how to communicate with the animal. Many tests have been made but none have been successful.
Dolphins have a natural sonar system called echolocation that helps them locate underwater objects. A dolphin locates an object by making sounds and listening for echoes the sounds make when reflected by the object. The sounds originate in the animal's breathing system.
The sounds are sent out of the dolphin's body through an organ called the melon. This organ lies within a bulge at the top of the animal's head. The United States Navy is conducting research to learn more about the dolphin's use of echolocation.