Cat and dog food, for thought

My friend Rhonda (@RKDrake) sends me to this pair of charts (in BusinessWeek). They are fun to look at, and ponder at. 

Here's the first chart:

 Should the countries be colored according to the distance from the Equator?

Is this implying that cats and dogs have different preferential habitats?

Is there a lurking variable that is correlated with distance from equator?

What is the relationship between cat and dog owners?

Is there any significance to countries sitting on that diagonal, whereby the porportion of households owning dogs is the same as that owning cats?

In particular, what proportion of these households have both dogs and cats?

If 20% of households have cats, and 20% of households have dogs, how much of these households are the same ones?

How are the countries selected?

Where does the data come from?

The data provider is named but is the data coming from surveys? Are those randomized surveys?

Are the criteria used to collect data the same across all these countries?

*** The other chart is about cat and dog food. Again, nice aesthetics, clean execution. Lots of questions but worth looking at. Enjoy.