Dolphins (海豚) are very beautiful and very nice animals. There are 17 different kinds of dolphins. Small dolphins, like Maui's dolphins, are only 1.2 meters long and 40 kilograms. The biggest dolphin, called an Orca, can be 9.5 meters long and 10 tons. It doesn't matter the size, though. All dolphins can talk. Maybe they cannot talk with words, but they can talk with sounds.
Dolphins like to swim beside each other. They travel in a group. We call a group of fish a "school". They do not study, but they travel together. Dolphins are mammals (哺乳动物), not fish, but they swim together in a school. Dolphins talk to the other dolphins in the school. They give information and they show their feelings. They tell when they are happy or sad or afraid. They say "Welcome" when a dolphin comes back to the school. They talk when they play.
They make few sounds above water. They come up out of the water because they need to breathe (呼吸) air. They make many more sounds under water. People cannot hear these sounds because the sounds are very, very high. Scientists make tapes of the sounds and study them.
Sometimes people catch dolphins for a large aquarium which is a zoo for fish. People can watch the dolphins in a show there. Dolphins do not like to be away from their school. They feel sad and lonely.
There are many stories about dolphins. They help people. Sometimes they save a person's life. Dolphins are very smart animals. They say that dolphins bring good luck. Many people believe this.
