Belongs to chordate phylum, vertebrate subphylum, mammals, eutherians, carnivores, split feet, canids. Also known as "dog" in Chinese, dogs are distributed all over the world. Dogs and horses, cattle, sheep, pigs and chickens are called the traditional "six animals". [13] Some scientists believe that dogs were domesticated from gray wolves by early humans, and the domestication time was 40,000 to 15,000 years ago. Known as "Man's Most Faithful Friend"