Dog behavior is responses coordinated internally (actions or inactions) of the domestic dog (individuals or groups) to external or internal stimuli. As the oldest domesticated species, with estimates ranging from 9,000-30,000 years BC, the minds of dogs have inevitably been shaped by millennia of contact with humans. As a result of this physical and social evolution, dogs, more than any other species, have acquired the ability to understand and communicate with humans and only are in tune with our behaviors. Behavioral scientists have discovered a surprising set of social cognitive skills in the domestic dog otherwise humble. These skills are not owned by kin canine dog or by other highly intelligent mammals such as the great apes. Rather, these abilities parallel some cognitive social skills of human children.