A dog tag is a small metal or plastic piece that hangs from a collar worn by dogs. It contains important information about the dog, like its name, phone number, and address. This information is helpful in case the dog gets lost and someone finds it. If the dog has a tag, people can contact its owner and help return the dog home safely. Just like how we wear our name tags at school or work, dog tags help identify and keep track of our furry friends.