Here's something curious. The phrase "man's best friend" didn't appear in print, according to Google's n-grams, until after the year 1750. Here's something else that's curious: the owning of dogs as pets by anybody more than the "one percent" - the richest of the rich - is also a relatively new phenomenon, something unique to the last two hundred years or so.

If dogs' vaunted status as honorary members of our human families is a relatively recent development compared to their domestication some 15,000 years ago, then just what were they doing all that time? One possibility: eating our trash.

In my latest at Nautilus Magazine, I explore what canine researcher Clive Wynne calls the "dumpster diver" hypothesis for domestication: Love Your Dog? You Should Thank Garbage.