Now, as far as I can remember in the United States dogs tend to lie down to sleep by effectively sitting. They lower themselves to the ground, but they still maintain the same general body posture as when standing. If this is wrong, I need to go play with some more pooches.
Argentine dogs are a different breed entirely (how's that for wordplay!?). In addition to there being an exorbitant amount of them around the streets of nearly every city (they lack years of Bob Barker reminding the world that spaying and neutering your critter is important), they lie down in a manner similar to a horse. Basically, they look like they've just fallen over on their side. This is fine and dandy, but the added effect is that, on a hot day, they look very much like they're dead.
I'll have to get some pictures and upload them soon. You know, after they fix my internet so that I can do more than write text...