
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 livestock guardian dogs,
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...