And yet: can we live with even a tortoise? Put aside dreams of lions in Manitoba and elephants in Texas — a tortoise. From Truth or Consequences, I head south, Chihuahuan Desert all the way, to Torreón, Mexico, where more than a million people live in a dead desert lake bed. I arrive, fingers crossed for luck, hoping to see the bolson tortoise living free and wild.

The next morning is grey. This is good, says Efraín Rodríguez Téllez — a researcher with the Instituto de Ecología who pulls up in a four-by-four crew cab — because it will soften the scorching heat of the day. On the other hand, overcast skies often produce tolvaneras, dust storms common enough to have their own warning signs on the freeway north.

The sky begins to clear almost immediately. By the time we take the turnoff for the Zona del Silencio, onto a dirt road leading to an immense bottomland cradled by distant mesas, there is no patch of shade larger than those cast by the fat seed heads of yucca plants. We get lost, of course. Despite laws to protect the tortoise in what is now the Mapimí Biosphere Reserve, a local rancher has cleared a new road to push his cattle into the playa, and Rodríguez mistakes it for the rough track to the Instituto de Ecología. Everywhere I look, there are cow-pies and hoof ruts, the latter worn shin deep in places. One of the world’s most inhospitable landscapes is still slowly being conquered.

At last we pull up, finding the institute’s buildings and courtyard teeming with Mexican students on a field trip, electric with the strange excitement of the desert. Rodríguez leads me to the back, where two chicken-wire shelters house a handful of bolson tortoises. One of them wandered into town with a large hole in its shell; the flesh underneath has yellowed into a gristly callus. Bored locals sometimes throw rocks at the animals, Rodríguez explains.

“Pobrecito,” he says. Poor little guy.

We drive out into the Bolsón de Mapimí, the sandy belly of a desert that was once a spreading, shallow lake. We roll at a tractor’s pace, searching the sparse brush for burrows or, with luck, a tortoise. Rodríguez knows the area, and stops regularly to inspect the telltale craters. In one, the hole is almost sixty centimetres wide, suggesting a tortoise that would comfortably fill a wheelbarrow. Most of the burrows show signs of life, such as droppings, or worn paths to utterly desiccated patches of grass. None reveals its inhabitant. This farthest reach of the bolson is the most desolate place I have ever seen; even the rocks seem to cluster together against loneliness. Still, there is something appealing about the site, a subtle lushness, like the layered horizons of a watercolour. We have at last left the cowshit and poached roads behind, and now the desert is alive with eerie noises and corner-of-the-eye movements. In the distance, somewhere, there is always a fine-bore dust devil turning.

People still eat the tortoises, says Rodríguez. “You ask people in the villages if they eat them, and they say, ‘No, no, no.’ But I was talking to a guy who was a little crazy, and he said, ‘Oh, yeah, I eat lots of them.’ As we say in Mexico, los comen de a madre.” Rough translation: they eat them like they’re going out of style.

“We’ll go a little farther,” says Rodríguez, bashing the truck directly over a creosote bush that is attempting to reclaim the fading track, “and then eat a little lunch in the shade.” He waits for my puzzled look: shade? “No,” he says with a laugh, “there isn’t any.”

But there is a tortoise. It is moving determinedly, the way tortoises do, across a gap between tufts of bush. It’s like a boulder on the landscape, though I later learn it is on the small side for an adult specimen. Rodríguez kills the engine. We step out of the truck, and I realize we are stalking the wild animal silently, like hunters. At a certain point, the tortoise suddenly snaps tight. It is unbelievably closed, vanished into itself with only its armoured forelegs exposed, and those completely hide its head. The tortoise is a fortress; it is also a jewelled box. With Rodríguez’s encouragement, I pick up the animal, bending to lift with my legs. Its weight reminds me precisely of an infant’s. Warmed by the sun, the tortoise contains the same powerful sensation of life within.

There’s not much else to witness: a tortoise is not a hunting lion, after all, or a trumpeting elephant. We go back to the truck, open a cooler, begin to make sandwiches. The weather is changing once again. On the southern horizon, a tolvanera is quickly stacking up in the sky, turning the daylight ruddy orange. I glance back to the tortoise, and it is perched again on its front legs, one cosmic eye upon us. The dust storm is sweeping toward us all, casting whirlwinds off its leading edge, dry lightning popping in its heart. In Torreón, they see the approaching tolvanera and say the rain is coming — an earthen rain. And it’s coming.

The tortoise is gone. It has picked its moment and disappeared. I wander out to where it had stood, not twenty paces from the truck, and begin to walk outward in a searcher’s spiral. The tortoise is nowhere. It seems impossible. I check the largest shrubs, the grassy islands. Gone.

Then the storm is on us. We retreat. The tortoise abides.