Although dog and cat are two lovely pets that people usually raise, but there are quite a few differences. If people do not know about these differences carefully, they will get in trouble to raise them. Thus, people should know and understand each characteristic well. First of all, dog and cat use different communication way. For example, when dogs wag tails, it means friendliness and happiness. On the other hand, cats wag their tails when they are afraid of something or angry.