According to fossil evidence, dogs were probably the first animals to be domesticated, at least ten thousand years ago. Domestic dogs developed from wolves that humans tamed and selectively bred for hunting, retrieving, and guard duties. Specific wolf traits appear in various dog breeds.
Domesticated dogs vary from small to large animals according to which breed or mix of breeds they represent, such as the tall wolfhounds, standing an average of ninety-nine centimeters (thirtynine inches) at the shoulder, the heavy St. Bernard weighing about 90 kilograms (200 pounds), and diminutive chihuahuas standing approximately thirteen centimeters (five inches) and weighing 2.7 kilograms (6 pounds). Each dog's skeleton has approximately 320 bones and varies according to tail length. Male dogs also have an additional bone, the os penis. Other exterior physical characteristics such as shape, color, and coat texture and length vary according to genetics. Puppies have twenty-eight temporary teeth, which they begin to shed around twelve weeks old, and adult dogs have an average of forty-two permanent teeth which emerge when they are six months old. Dogs have twelve small incisors, which they use to groom themselves and to carry objects. Four large, sharp cuspids, often called canines, are used to tear meat, the foundation of dogs' diets. A total of twenty-six premolars and molars chew food. Wild dogs hunt a variety of prey, mostly small mammals such as rabbits, squirrels, and rodents. Dogs have nonretractable claws and walk on their toes. They have five toes on their front paws and four toes on their hind feet, where occasionally there is a dewlap or extra toe. Because they cannot perspire, dogs pant with their tongues to cool their systems.
Thanks for description - Animal life club