Can dolphins talk? Maybe they can't talk with words, but they talk with sounds.

    Dolphins travel in a group. We call a group of fish a "school". They are not fish. Instead, they are mammals (哺乳动物), Dolphins talk to other dolphins in the school. They give information. They tell others when they are happy or sad or afraid. They say welcome when a dolphin comes back to school. They talk when they play.

    They make a few sounds above water. They make many more sounds under water. People can't hear these sounds because they are very high. Scientists make tapes of the sounds and study them.