Long ago, some brazen wolves started hanging around human settlements, jump-starting events that ultimately led to today's domesticated dogs. Now geneticists say they have identified one of the key changes that turned wolves into the tame, tail-wagging creatures well-suited to living by our sides — the ability to digest carbohydrates with ease.
Comparing dog and wolf DNA, the authors pinpointed several changes in starch and sugar-processing genes that would have made early dogs better able to digest the scraps they scavenged from dumps in early farming villages, helping them to thrive as they gave up the independent life of the pack to entwine their lives with ours.
This means that at some point in dogs' evolutionary history, packs of wild canids struck up a mutually beneficial relationship with early humans, and learned to subsist on people food — stuff like wheat, barley, corn, rice, and potatoes. In exchange, man earned himself a loyal friend and fierce protector.