Swedish researchers have an intriguing new theory on why dogs became the human pals they are today, as opposed to wolves: They developed the ability to digest starch, which allowed them to live off the refuse of our human ancestors at the dawn of agriculture, reports the Washington Post. Wolves remained carnivores, but the dog branch of the family could eat wheat, rice, potatoes, and the like. As it turns out, humans were undergoing a similar change about the same time.
“I think it is a striking case of co-evolution,” says a geneticist at Uppsala University. “The fact that we shared a similar environment in the last 10,000 years caused a similar adaptation. And the big change in the environment was the development of agriculture.” As one theory goes, dogs eventually grew to tolerate human contact and were brought into settlements to be guards and pets.