Dog is a domestic animal in the form of wolf. The term dog is used for both the pet and feral dogs. In the human history dog is one of the companion and working animal. More than 15,000 years dog became a domestic animal. Domestic dogs are selectively having many more breeds with different characters, behaviors, capability of sensors etc. Modern dogs showing many variations in colors, sizes, shapes, behaviors and many more. The dogs are mammals, the dogs having powerful muscles, strong bones, strong teeth for biting and tearing a long tail. The dogs may vary in weight and heights. The eyes of the dogs are having many dimensions, shapes, and retinas. the sound frequency of sound hearing in dogs are 40 Hz to 60,000 Hz. in modern tradition humans are placing a dogs shows also where the dogs used to wear cloths and make up. The dog collars are also made for all shapes and sizes of dogs.