A: Like many other things, Anglophilia is at the heart of the answer, as is Paul Fussell's must-read 1983 classic Class. While MB-dom and class is not a 1:1 correlation we think his observations on dogs are quite astute:
They are classier the more they allude to nonutilitarian hunting, and thus to England. The top dogs consequently are Labradors, golden retrievers, corgis, King Charles spaniels, and Afghan hounds. To be upper-class you should have a lot of them, and they should be named after the costliest liquors, like Brandy and Whiskey. The middle class goes in for Scotties and Irish setters, often giving them Scottish or Irish names, although it reserves "Sean" (sometimes spelled "Shawn" to make sure everyone gets it) for its own human issue. Proles, for their part, like breeds that can be conceived to furnish "protection": Doberman pinschers, German shepherds, or pit bulls. Or breeds useful in utilitarian outdoor pursuits, like beagles. The thinness of dogs is often a sign of their social class. "Upper-class dogs." says Jilly Cooper, "have only one meal a day and are therefore quite thin, like their owners."