I think that the most interesting animal is dog. Although it is common, it is really smart and considered as human friend. There are many kinds of dogs in the world. Therefore, the shapes of dogs are different, depending on many factors, such as age, blood, even sex. Generally, they have for legs and a tail. The organs on their faces are similar to human, which means they have a nose, two eyes, two ears and a mouth on their faces. It is very acute. When I was a child, my family had a little dog named Candy, which means he brought our lives happiness. As he was not strong, he can live in a special wooden house in the garden. It is a white wooden house that my father and me made for him. the main reason why I think dogs are interesting animal is that children like to play with it and of cause, they never hurt children in common occasion. Therefore, parents believe they are more reliable than other animals. As for some special kinds of dogs, such as police dog, they can protect social safety.