The Null Device
The Washington Post's data-journalism blog has a piece on the relative popularity of cats and dogs, by US state and by country.
In summary, in the United States cat people tend to live around the coasts and in the north, adjacent to the Canadian border, though parts of the Midwest also lean cat; the South, meanwhile, leans dog (with the exception of Florida), with the southwest being most strongly dog. On a worldwide level, though, the US leans cat (albeit weakly) in aggregate, as do Canada, Russia and most of Europe (with the exceptions of Ireland, Poland, the Czech/Slovak republics and the Iberian peninsula, all weakly dog; Switzerland, meanwhile, is strongly cat). The Islamic countries tend to lean strongly cat (presumably for religious reasons, dogs being regarded as unclean). Meanwhile, Australia is weakly dog, as is Brazil; the Spanish-speaking Americas are strongly dog-leaning, as are China, India, Thailand and South Africa. (New Zealand, however, is strongly cat.)
The cat/dog dichotomy is, at least in places, partly political. In the US, the data approximates (albeit imprecisely) the red-state/blue-state divide between conservative- and liberal-leaning states; the most cat-favouring states tending to be the progressive strongholds of the coasts (notoriously liberal Massachusetts has a 2:1 cat:dog ratio, for example); meanwhile, the states most identified with conservative mindsets (open-carrying, convict-executing Texas, Sheriff Joe Arpaio's Arizona, Mississippi) lean most strongly towards dogs. (An exception is Florida, which narrowly favours cats.) This correlation between political identity and pet preference is borne out in surveys, which show that US liberals are more likely to be cat people (among other things). There are several possible explanations: one could be the correlation between population density and liberalism (city folks lean more liberal than rural/small-town people), and cats being more suitable for smaller living spaces than dogs. Another explanation ties to the theories recently floated by the likes of George Lakoff and Jonathan Haidt; in short, conservatives place more of a premium on loyalty, obedience and knowing one's place in a hierarchy; all of which are exemplary qualities of Canis familiaris. Cats, meanwhile, fail this test, and hence get little love from the right (with the possible exception of libertarians; it has been pointed out that both domestic cats and libertarians are highly dependent on their environments whilst imagining themselves to be wholly sovereign and autonomous). Meanwhile, this piece replicates the correlation between cat appreciation and liberalism (using Facebook likes s a proxy), adding that conservatives seem to be generally less fond of animals, with those liked getting an exception for their utility or symbolism (the animals most liked by self-identified conservatives on Facebook have been deer, eagles and, most of all, turkeys; liberals, meanwhile, like only bats and whales more than cats).
Worldwide, trends become murkier; Russia, styling itself as the core of a new “Conservative International”, is cat country by a 4:3 ratio. Spanish-speaking Latin America has dogs outnumbering cats by more than two to one (with Portuguese-speaking Brazil being slightly more equal); perhaps there's something in Hispanic culture which strongly favours dogs or deems cats inadequate as pets? And while Australia is dog country by an almost 3:2 ratio, New Zealand has twice as many pet cats as pet dogs. It is not clear whether that is a sign of Australia being a more intrinsically conservative country, and it would be interesting to see whether this ratio tracked (or was tracked by) changes of government and culture.