San Miguel de Allende, Mexico - To wander among the working-class neighborhoods here is to think, at times, that the world is a cacophony of barking dogs. When the sun goes down, in the middle of the night and at first light, they bark. "How long can they keep it up?" I have often asked myself.

For the first few years I lived here, those sounds startled me. Now I find myself growing somewhat accustomed to them, inured, or maybe just plain resigned to their inescapable presence.

When I go to the local store, often accompanied by my lively little dog, Lola, we are often greeted by howling heads, thrust, jutted, skewed - peering down from rooftops, their bodies contorted, sometimes leaping in an almost comical abandon - or teeth bared and snarling, or at times crying aloft, like cartoon hounds. Meanwhile Lola darts to and fro, safe in the knowledge that if any danger exists, it is usually at least one or two stories above.

These roof dogs spend much of their lives up there, surveying their territory from an advantageous perch. But great as the views are and as much as their height adds to their sense of superiority, they are not there by choice. My friend and neighbor Pedro Moncada says the dogs are a kind of early warning system, a rooftop alarm. But that's not all: He believes that dogs somehow know things we don't. If someone nearby is going to die soon, he said, they bark throughout the night.

A local ironworker scoffed at the very thought and between hammer blows, he huffed that they were just there as a scare tactic. Either that or their owners were lazy, or just didn't have room in their cramped quarters.

Pedro says that he has three dogs, but that doesn't mean he understands their minds.

"All I am certain of," he said, "is that dogs are very mysterious."