The short and quick answer is that animals are all about energy and observation. Animals like dogs, cats, horses and other animals that have been domesticated have developed how to read our energy. It is a basic survival ability of theirs. If you are a person animals are attracted to take it as a huge compliment of your energy. Animals that live with us are watching and learning about our behaviors all the time. They learn from our patterns and how we live our daily lives. If an animal does not know a person, they will go by their learned ability to trust certain types of energy.