The domestic dog originated from gray wolves and was the first species domesticated by humans. Through selective breeding over thousands of years, dogs have developed behaviors and physical traits suited to assisting humans. They live closely with people and rely on humans for food, though their social nature and ability to thrive on human-made diets allow them to be valued companions. As the most populous carnivore, dogs fill various roles from hunting to service work. Caring for a dog requires meeting their complex needs over a 12+ year commitment as their devoted caretakers.