Ancient Places (20 page)

Any thatching ant mound is a key predatory factor on the insects within its sphere, and this supercolony provided researchers with an opportunity to gauge that influence on a very large scale. When biologists ran the numbers, they realized that the combined population of all the mounds could easily consume the number of spruce budworms required to defoliate a forest stand of comparable area. Subsequent surveys indicated that the acreage within the ant supercolony had sustained significantly less damage from the spruce budworm outbreak than surrounding forest tracts.

In an attempt to measure the density of the thatching ant population outside the study area, researchers walked transects through surrounding patches of defoliated and logged-over Blue Mountain forest. In all, their census covered one hundred miles of trails. Along that entire length, they did not find a single ant mound.

“That’s what I mean,” said Dr. Hansen, “when I say I don’t know anything about thatching ants.”

She reached up to lightly thump the top-side watering system, causing the bottle caps to sprinkle drops on top of the thatch. “They’re supposed to be in torpor, but a few always come up to meet the moisture.”

Sure enough, individual workers immediately began to emerge from the desiccated tunnel system to check out the fresh
water drops. As they skittered back and forth, one stumbled across a pile of dead ant bodies that lay heaped in a corner. “Oh, yes,” said Hansen. “Part of getting organized is separating out all the recent mortality. If you watch long enough, you’ll see some workers hauling up the day’s bodies.”

As she spoke those words, I thought of a story told by a man named Barnaby, a member of the Saint Mary’s band in the Kootenay region of southeastern British Columbia. More than a century ago, Barnaby recorded a long and complicated Raven tale for an anthropologist. As the story unspooled, Raven lost a son and a daughter in separate grisly accidents. Raven was recounting their fates to a village chief when Ant suddenly appeared to act as the designated gravedigger.
“Ant tightened his belt in order to bury the dead,” said Barnaby. “He almost cut himself in two, and was small in the waist after that.” Laurel Hansen and I looked at the ants in her glass case, both alive and dead, and I wondered what else Barnaby understood about them.

In 1810 French zoologist Pierre Huber observed that individual thatching ant mounds were cleverly engineered to present a favorable exposure to the sun. He realized that the amalgamation of materials on the outside of each mound provided protection against hard rain, wind, and extremes of temperature and humidity. Inside the structure, rich organic materials supplied insulation and food for the colony’s interconnected shafts, galleries, and egg chambers that reached just as far beneath the ground as the top of the mound rose above it. It was Huber who first suggested that the primary function of these mounds might be microclimatic regulation. His notion helped me lure Dr. Hansen into an August stroll through the same stretch of
piney woods where, earlier that spring, my group of students had gathered around a busy mound of thatching ants to watch them operate in the wild.

In the late summer’s sun, several of the older ponderosas showed the thick outer bark that glows like a ruddy sunburn and supposedly marks the passing of a tree’s first century. Bunchgrass filled the space between them, with a few late lupines and heavily scented yarrow plants standing out among the tussocks. The serviceberries had shrunk to tiny black raisins by this point in the season, but hawthorn berries were just beginning to come on.

Dr. Hansen stopped at a good-sized pine snag to pry on the fissures between its bark. Plates popped off like pieces of a jigsaw puzzle, filling the air with a vanilla scent. Before many moments had passed, she paused and drew her head back from the tree. Looking for big black carpenter ants, I leaned in but saw nothing. Then a smell like rotten coconut began to overtake the delicate vanilla of the pine. Following Hansen’s gaze, I spotted smaller ants, lots of them, traversing the freshly exposed layers of bark.

“Velvety tree ants,” she said. “Look how they’re running with their butts up in the air. They’re spraying a pheromone that makes that rotten smell.”

The ants were so small and quick that it took several more moments to see that each one had its abdomen tilted up at an awkward angle. Dr. Hansen snatched a single worker out of the mob and trained her lens on the soft abdominal hairs that inspired its name.

On the next tree we came to, the simple turn of a downed limb exposed a carnival dance of another small species of ants, and Dr. Hansen wandered over to appraise them. “We call these crazy ants. See how long their legs and antennae are
in proportion to their bodies? That’s what makes it look like they’re running crazy. They’re a tramp species, always hitching rides from one place to another. Customs agents see them all the time. No idea where they originally started from. No idea where they’re going.”

“But if these crazy ants rely on humans to move from one place to another,” I asked, “what are they doing out here in the woods?”

“Well,” replied Dr. Hansen, “maybe they know more than one way to live.”

It was late afternoon by the time we approached the lone pine with the thatching ants’ hill at its side. The fruits on the golden currant bush remained tasty, if a bit past their prime. We were able to step right up and pick them because the ant mound, which had swelled with a pulsating fury during my first encounter three months before, had somehow shrunk in size so much that for several minutes I thought we had come to the wrong place. At our feet, the great nest amounted to little more than a patch of scattered duff, with not a single ant in sight.

While I poked at the needle-strewn ground, trying to uncover a spark of activity, Dr. Hansen watched impassively. “What’s going on?” I asked, looking to her for help. “Do they settle in for winter this early?”

She shook her head. “I guess some do, but there’s more going on here than that. This mound has died. Ant colonies have a life span, just like anything else.”

Stretching my arms out like the schoolgirl did in May, I tried to demonstrate how large the tumulus had been then.

“All that energy inside, all that work and movement, combine to puff their material way up,” said Hansen. “If the colony is not alive, the duff flattens right back down. But don’t take
it personally. Next spring we can find as many new mounds as you want to puzzle over. I’m pretty sure thatching ants will be around long after we’re gone.”

The way it turned out, not more than a couple of weeks went by before a friend relayed a message to me from the Spokane Reservation. On a sandy bluff above the mouth of the river, she and her husband had found the biggest anthill anyone there had ever seen—as tall as a man and even larger across. The photograph they sent showed one of them standing next to it, holding up a walking stick for scale. Looking at that massive mound, it was hard not to compare it to a termite structure in Africa, one of those exotic hoodoos that Laurel Hansen used to dream about before she discovered an architecture just as interesting, much closer to home.

The thing about geology is that it never stops.
“No causes whatever have … ever acted, but those that are now acting,” wrote the pioneering Scottish geologist Charles Lyell, “and they never acted with different degrees of energy from that which they now exert.” According to Lyell’s insight, the earth has always turned, and will continue to turn, like a kaleidoscope of unfathomable scale. Massive floods will rearrange the landscape. Lava flows will ooze from volcanic vents. Deeply buried ocean sediments will return to the surface in reconstituted form. Although human existence spans only a tiny arc in the rotation of this spinning time machine, Lyell asserted that an observant person could make sense of all the constituents because the ongoing
processes have remained consistent. Visual clues lie in plain sight, like distinct glass shards that reappear in each new turn of the kaleidoscope.

Such clues are scattered across the Okanogan Highlands in what is now north central Washington State and adjacent British Columbia. Around a hundred million years ago, a crescent of volcanic islands that geologists call Quesnellia docked against primordial North America. During its initial contact, this terrane overrode the continental basement rock in a long slide that raised the elevation of the land between the Rockies and the Cascades several thousand feet above its present level. In effect, Quesnellia’s overthrust thickened a portion of the earth’s crust. It is a geological tenet that such disproportions tend to even out over time.

By the turn of the Eocene epoch, a fault beneath the margin of Quesnellia’s collision extended to the earth’s mantle. From that molten source, a batholith of magma filled the empty space, creating pressure and fractures within both the basement rock and the overthrust terrane. The magma funneled up through the cracks in a pulsating series of events known as the
Sanpoil Volcanics, which left igneous flows puddled over the top of the Quesnellia formations. Further batholithic forces fractured both the new and old horizons into a series of tangled uplifts. As the pressure abated, the earth’s crust was stretched and thinned. The more brittle upper crust cracked into fault blocks that slipped and slid against each other like books slumping across a loosely packed shelf. Depressions between the angled bookends filled with fresh water to form substantial lakes.

The timing of the Sanpoil Volcanics, a bit more than fifty million years ago, coincided with a warm, mild Eocene climate. After the geologic activity settled down, the conditions gave rise
to a temperate upland forest around the edge of one lake that touched the site of the modern town of Republic, Washington. Similar forests, surrounding similar lakes, arose within the thickened edges of overthrust islands that extended north and west all the way to Smithers, British Columbia. These Eocene forests and lakes supported roses and witch hazel, palm beetles and salmon, songbirds and crawdads.

Species lived, died, and sank to the bottoms of the scattered high lakes for thousands of years. Light volcanic ashfall and seasonal flood events introduced sediments that covered the detritus with just the right delicate velocity to preserve leaf surfaces, flower buds, spider bodies, and the tracery of horsefly wings. Over longer spans of time, the weight of these sediment layers pressed the organic images into fossils of exquisite detail.

Then, as the kaleidoscope began to turn again, the crust below the Okanogan Highlands slowly settled into the rolling domes and faulted exposures we see today. Those long-buried lakes remained remarkably undisturbed by the variety of geologic events that continued to shape the region. Even after commercial miners arrived to explore for veins of precious ore that had flowed close to the surface during the Sanpoil Volcanics, many components of the temperate Eocene forest slumbered on in their mudstone beds—each one a bright shard from the distant past, waiting to be revealed.

In the summer of 1977, a pair of volunteers from the University of Washington’s Burke Museum crossed the North Cascades for a weekend fossil hunt in the Okanogan Highlands. Teenaged Kirk Johnson served as chauffeur for Wes Wehr, a self-taught paleobotanist who, although he was pushing fifty, had never learned
to drive. Their first target was Republic, a small gold-mining town where leaf fossils had been collected haphazardly since the late nineteenth century. Most experts had assumed the imprints were associated with Miocene leaf fossils found in clay beds farther south and had moved along to other sites.

Wehr and Johnson wandered along a drainage ditch across the street from Republic’s city hall without finding anything and were close to getting back in the car when Johnson kicked a laminated rock. Before his foot had settled back to earth, the pair found themselves staring at
the clear imprint of a dawn redwood twig. Soon they discovered several more troves of fossil-rich shales exposed by roadcuts and former mining digs along the base of a knobby outcrop called Boot Hill. It took a little longer to establish that what they had stumbled upon was not a Miocene forest of the sort they knew from the Columbia Basin, but rather the bed of a much older Eocene lake. For Johnson, that lucky kick helped to shape a paleontological path that led from Boot Hill to the Denver Museum of Nature and Science, and on to the Smithsonian Institution. For Wehr, already well along on a serendipitous life journey, the incident provided a focus that drew on all his eclectic qualities.

Wes Wehr had been born on the west side of the Cascades in 1929, and from an early age his precocious intelligence led him to pursue both classical music and concrete connections to the composers he adored. A letter-writing campaign brought him the autographs of Arnold Schoenberg, Dmitry Shostakovich, Jean Sibelius, and Igor Stravinsky. Always one to look beyond the obvious, Wehr then began to diversify his signature cache until it included blues progenitor W. C. Handy, Henri Matisse, George Bernard Shaw, and Albert Einstein. As a teenage usher at a popular Seattle theater, Wehr reveled in the thrill of interviewing
luminaries ranging from Bela Lugosi to Paul Robeson for his high school newspaper.
He learned when to linger in the shadows backstage, and when to make a decisive introduction.