Into thin air

THEY lived on the edge of the world, in the red mountains of the desert Southwest, in houses with T-shaped doorways tuned to arcane celestial events. They fashioned elaborate pottery, grew corn and beans in obdurate soil, built ceremonial chambers (kivas) dedicated to sun, stars and gods. By the 11th century, they were a highly evolved, technological society. And then, suddenly, they were gone. “Farming implements were left in the fields,” writes naturalist and desert ecologist Craig Childs in “House of Rain.” “Ceramic vessels remained neatly stowed in their quarters; ladles rested in bowls as if people had been swept from the land by an ill and sudden wind.”

Or so the story goes. As Childs explains it, no one really knows what happened to the ancestral tribes of the Southwestern canyons now lumped together as the Anasazi. Their disappearance has captivated modern explorers, professional and casual. It is a mystery pieced together from tree-ring patterns in fallen roof beams, pottery shards, human bone fragments unearthed by archeologists and hikers (one of them a Boy Scout whose flashlight fell down a hole). Any number of solutions to the mystery could be true.

In “House of Rain” (the title refers to the dwelling of an ancient god), Childs does not undertake to solve the mystery or referee among bickering archeologists. Instead, he sets out to ramble through the ancient canyons with their crumbling kivas, to linger over the pottery shards and human bones and to interview the archeologists who have devoted their lives to understanding these ancient people whose very name is in dispute. “The word ‘Anasazi’ was crafted by the Navajo, who in the 1800s were paid by white men to dig skeletons and pots out of the desert,” Childs writes. Long thought to mean “old ones,” it in fact translates as “enemy ancestors,” which naturally angers the Anasazi’s descendants, who include the Hopi and Zuni tribes. Midway through the book, Childs simply abandons the appellation, which, he explains, “had grown fainter with every mile I had traveled.”

Childs’ journey begins at Chaco Canyon, in northwestern New Mexico. From there, he treks to Utah and then south again, to the ancient northern Mexico town of Paquime (now Nuevo Casas Grandes), where a later civilization much like the Anasazi flourished. Sometimes, Childs travels with his wife and their baby son, allowing him to ruminate on the intricacies of tending to a toddler on the trail. Sometimes, he travels with friends, with whom he negotiates flash-flood channels and vaults over crevasses. It is a somberly focused, physical trip, and you learn at the outset just how precisely he will describe it. (“At the river I untied the canoe’s bowline, stepped in, and swept the paddle into the water, setting a wake across a mirror of stars.”)

You can open to almost any page in “House of Rain” and find an evocative line of prose. Every object is active and vivid: Tires “gobbled at paprika-colored sand”; flies land “to sip sweat off our forearms”; wind “scrapes and hisses across the red, bare earth.” Whether you savor such tactile accounts as Childs rousing himself from his sleeping bag or setting his baby’s “diaper-padded bottom” on the back of a truck depends on how much time you have and how badly you want to solve the puzzle of Anasazi history. But if you decide to hurry to the end of this lovely book looking for answers, you will be disappointed. Childs has done casual scholars of the prehistoric Southwest a great favor by compiling so much information so fluidly in a single volume; he has not, however, sorted it in a way that makes sense of the ancient peoples’ end.

What happened to the great civilizations of the Southwest that flowered so exquisitely and flickered out so abruptly? In addition to the Anasazi, there were the Hohokam, who built complex irrigation systems near what is now Phoenix. And then came the Salado, “a massive cultural convergence based in east-central Arizona, where migrants collided with numerous indigenous heritages that had been in place for centuries.” (Like “Anasazi,” the name refers to an epoch rather than a unified tribe.) At Paquime, a vibrant people kept birds for sport and food, built great houses and watered their fields. By the end of the 15th century, some 200 years after the disappearance of the Anasazi, all these indigenes were gone. When the Spanish arrived in the 16th century, they “probably met with only small, scattered populations, feeble resistance to thundering columns of conquistadors clad in leather and steel.”

Was the vanishing of these civilizations hastened by the consumption of too much corn, which is rich in fat and protein but disastrously low in the amino acid tryptophan, chemical precursor to the mood-stabilizing neurotransmitter serotonin? Did they destroy their forests too quickly and render their already restless climate too hot to inhabit, like an early version of an urban heat island? Or did they all simply move out of the frame where later cultures expected to find them -- the relatively small square of Southwestern land where most of their relics have been found?

And before any of that happened, were they all in some way related? It’s possible, Childs writes, that the Anasazi migrated through the centuries along a 400-mile line from Chaco down to northern Mexico. As the Anasazi culture began to destabilize, the people of Paquime arose, with dwellings that featured the Anasazi’s T-shaped doorways. Among the more fascinating characters in “House of Rain” is archeologist Steve Lekson, who tells Childs, as the two knock back a few beers, that the architecture of Paquime was no accident; one of his scholarly papers notes that “Chaco and Paquime have been the subject of sordid, tittering speculation for some years.” Childs later learns to use Lekson’s name sparingly in the presence of other archeologists but nevertheless insists that “his ideas seem to be pointing in the right direction.”

Lekson’s theory does not explain, however, where the Anasazi went, after their possible dalliance at Paquime, and that’s what we want to know -- now more than ever, at least in part because, in this time of weird weather patterns and war, we worry that what happened to them might happen to us. Historians and archeologists have long blamed bad environmental practices, but Childs proposes still another theory: Invading Salado hordes, with their too-colorful, thin-walled pottery (produced in Wal-Mart-like quantities, from poor clay), brought their “raving, polychrome ideologies” with them. They prayed too much, built too much, squandered cotton, water and goodwill. The last remnants of the Southwest’s ancient cultures bear Salado marks on their pottery, “painstakingly intricate bands painted around exterior bowl rims and jar necks, as if people were frantically squeezing their signatures onto what little unpainted space remained, making their last desperate claims in a time of social collapse.”

Childs does not mention some key theories -- such as UCLA geographer Jared Diamond’s contention, in “Collapse,” that deforestation and drought made the Anasazi vulnerable to interlopers, environmental collapse leading to the social kind. Nor does Childs, in the end, draw firm conclusions about the fall of the pre-Columbian Southwest. “House of Rain” is neither a political book nor a tendentious one. It is a book that sets the reader’s imagination to work on a problem that has confounded generations of archeologists and probably will continue to do so for many years to come. *