The intriguing question in the title comes from an inscription on the collar of a dog Alexander Pope gave to the Prince of Wales. When Pope wrote the famous couplet "I am his Highness' Dog at Kew, / Pray tell me Sir, whose Dog are You?" the question was received as an expression of loyalty. That was an era before there were dog breeds and, not coincidentally, before people were generally believed to develop affectionate bonds with dogs. This interdisciplinary...