Stud dog

Dog breeding is the practice of mating selected dogs with the intent to maintain or produce specific qualities and characteristics. When dogs reproduce without such human intervention, their offsprings' characteristics are determined by natural selection, while "dog breeding" refers specifically to the artificial selection of dogs, in which dogs are intentionally bred by their owners. A person who intentionally mates dogs to produce puppies is referred to as a dog breeder. Breeding relies on the science of genetics, so the breeder with a knowledge of canine genetics, health, and the intended use for the dogs attempts to breed suitable dogs.

Few hours old

Three days old

Few weeks old

Seven weeks old

Twelve weeks old

Humans have maintained populations of useful animals around their places of habitat since pre-historic times. Over these millennia, domesticated dogs have developed into distinct types, or groups, such as , hunting dogs, and sighthounds. Artificial selection in dog breeding has influenced behavior, shape, and size of dogs.

Some researchers believe that the evolution of dogs from wolves is an example of neoteny or paedomorphism selection, that results in a retention of juvenile physical characteristics. Compared to wolves, many adult dog breeds retain such juvenile characteristics as soft fuzzy fur, round torsos, large heads and eyes, ears that hang down rather than stand erect, etc.; characteristics which are shared by most juvenile mammals, and therefore generally elicit some degree of protective and nurturing behavior cross-species from most adult mammals, including humans, who term such characteristics "cute" or "appealing". It has been seen that these traits can even prompt an adult female wolf to act more defensively of dog puppies than of wolf puppies. The example of canine neoteny goes even further, in that the various dog breeds are differently neotenized according to the type of behavior that was selected. Other researchers believe that because this comparison is based on the gray wolf, which is not the ancestor of the dog, that this comparison is invalid. Further research indicates that the concept of neoteny as a means of distinguishing dogs from wolves is baseless.

...
Wikipedia