Analog SFF, November 2007

by Dell Magazine Authors

  Gorilla nappies.

  I'm afraid the road to the future will be more trying for the lord bishop of Exeter than even he imagines.

  Copyright (c) 2007 Barry B. Longyear

  (EDITOR'S NOTE: Jaggers and Shad appeared earlier in “The Good Kill" [November 2006] and “The Hangingstone Rat" [October 2007].)

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  IN TIMES TO COME

  Jean-Pierre Normand, the artist who captured an impressive four of the top five spots in last year's AnLab vote for Best Cover, has an original for our December issue, illustrating C. W. Johnson's novelette “Icarus Beach.” It's a challenging story to illustrate, about a challenging situation, to say the least: much of it takes place inside a star that's about to undergo, shall we say, a major shake-up. Might sound completely impossible, but then, the author is a trained professional (astrophysicist). Don't try this at home!

  Kevin Walsh's fact article, “Finding Planemos,” surveys the relatively new business of finding extrasolar planets and similar objects: what can now be done, what's been found so far, and the prospects ahead. We'll also have a variety of other items by familiar authors like Robert R. Chase, Jerry Oltion (an unusually thought-provoking seasonal piece), and Geoffrey A. Landis, as well as introducing a

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  THE SEARCH FOR THE WORLD'S FIRST EQUESTRIANS by RICHARD A. LOVETT

  Once, there was a boy. Or perhaps a girl, but in the cultures of the time, a boy was more likely. We'll call him Khan, although the language groups from which that name would arise wouldn't evolve for thousands of years.

  Khan was a hunter—perhaps a young one, still fresh with innovation. One day, as he, his father, uncles, and brothers stalked the thundering beasts of the plains, they cornered a mare in a box canyon, killing her with spears, arrows, and stones. But the mare had a foal that stood trembling nearby, torn between panic and the instinct to stay by its mother.

  There were plenty of men to butcher the mare and carry the meat home, and as they set to work, Khan watched the foal. There, he realized, was more meat: not that anyone needed it at the moment. But if he could get it home alive, and if it was old enough to survive, he could keep it until meat was again needed.

  Carefully, he fashioned strips of rawhide into a longer line. More carefully still, he approached the foal and wrapped the line around its neck, like he sometimes did with the dogs that lived in his village, sharing meat and fire and hunting with his clan. And slowly, cautiously, he led the foal home.

  The foal lived and grew. Hunting was good, and so it was allowed to live, through winter and into spring and on to the next year. By this time, it was a pet—a source of meat only in the direst of emergencies. Then, Khan had another idea. The foal had become large and strong: far larger than the dogs that, as a child, he'd tried to sit on so they could carry him, laughing, around the village until the elders said dogs weren't made to be sat on and besides, they would bite if you played too rough.

  The horse was bigger than the dogs.

  One day, Khan led it to a large rock. He climbed onto the rock, and from there, leapt to the horse's back. The animal flinched, but did not buck or try to run. And the course of humanity shifted forever.

  * * * *

  Okay, it probably didn't happen exactly like that. More likely, there were many Khans who independently made the same discovery, again and again. But someone had to be first, and the smart money says it probably happened on the Asian steppes, perhaps six thousand years ago.

  Trying to prove it, though, has kept archaeologists busy for years.

  Archaeology is one of the favorite fields of science fiction. It's perfect for adventure stories: rife with mystery and shadowy stories of origins—a realm of vanished civilizations and priceless treasures. But real archaeology isn't Indiana Jones. Yes, the occasional Incan or Egyptian treasure surfaces. In 2005, for example, a team of American and Italian Egyptologists found pieces of the world's oldest seafaring ship, along with a four-thousand-year-old cave on the Red Sea, where Egyptian sailors had created a supply base, then mothballed it. Inside, they found coils of rope and other supplies, neatly stacked for a return that never came.

  But such finds are headline-grabbing rarities. Rather than clambering around in teetering ruins, the real work of archaeology increasingly involves chemistry, remote sensing, and even laboratory experiments. Such in fact, is the case with the search for the first signs of horse domestication. This article focuses on horses, but if we ever find traces of vanished civilizations on other planets, the odds are that the work of piecing them together will have a lot more in common with this than with Tomb Raider.

  First of all, let's define what the horse researchers are looking for. Our friend Khan didn't domesticate anything. He caught a wild horse and tamed it. True domestication involves captive breeding.

  This turns out not to be easy. Horses are big, unruly animals, and stallions can be mean. Compared to raising a wild foal as a pet, breeding horses in captivity is a much more difficult task, says British researcher Marsha Levine of the McDonald Institute for Archaeology at the University of Cambridge.[1] In the early days, she argues, it would have been simpler just to capture foals and tame them on an as-needed basis. In fact, she notes, only a few hundred years ago the Plains Indians still preferred stealing horses or capturing wild ones to breeding their own.

  [FOOTNOTE 1: Levine's theories, presented in more detail on her web site, www.arch.cam.ac.uk/~ml12/index.html, inspired my own tale of Khan.]

  * * * *

  Clues in their Genes

  Obviously, there did come a time when horses were domesticated. One interesting line of evidence about the manner in which this came about can be found in the genes of modern horses (including today's “wild” ones, which are simply domestic escapees). A 2001 genetic study by biologists at UCLA and three Swedish universities, for example, examined their mitochondrial DNA, which is inherited from their mothers.[2] It found that modern horses are descended from a large number of wild mares, probably from diverse areas.

  [FOOTNOTE 2: Mitochondria are cellular powerhouses that help “burn” food to provide energy. To do this efficiently, they contain their own DNA. Mitochondria, with their DNA, are passed from mother to child via the protoplasm of egg cells, rather than from father to child via sperm. This has been used to determine that all humans appear to be descended from one great-to-the-nth grandmother, the so-called “mitochondrial Eve.” The work with horses is similar, but reaches a different conclusion.]

  Initially, that was taken to mean that horse domestication arose independently in a number of cultures. Then, a more recent study, published in 2004 in Nature Genetics, revealed that the male Y chromosomes came from a far more limited number of stallions. This may mean that horses were domesticated by one single clever tribe, and that as the idea spread, others captured additional wild mares but mated them with domestic stallions obtained from their neighbors. That certainly makes sense. Mares are easier to capture and tame, so if there are wild horses around, you might as well get your own, for free. But stallions are a different matter, and if domestic ones are already available, most people might rather trade for one than risk their lives trying to capture a wild one.

  Either way, Sandra Olsen, an archaeologist at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania, believes horses were first domesticated on the Eurasian steppes, that broad swath of grasslands that sweeps from Mongolia to Russia.

  For more than a decade, she has been excavating villages from the Botai culture of what is now northern Kazakhstan, looking for evidence that 5,600 years ago, they were already relying heavily on horses for meat, tools, and transportation. These villages are one of two sites vying for the honor of having the earliest signs of horse domestication. (The other is a similar-aged village called Dereivka, in Ukraine.)

  There is no doubt that horses played a major role among the Botai. In one village, Olsen's team has recovered more than 300,000 ani
mal-bone fragments. “Of those, over 99 percent are from horses,” she says.

  Nor has Olsen's team found any indications that the Botai engaged in agriculture. “It was a horse-centric society,” she says.

  Levine counters that the villagers may also have eaten fish. “We don't know that they were subsisting entirely on horses,” she says. “Fish bones don't preserve well, archaeologically."

  Still, horses were obviously important to the villagers. (The same is true for Dereivka, which also contains a startling number of horse bones.) Cut marks on the bones indicate that the horses were butchered for meat, and Olsen thinks there is no way the villagers could have killed that many horses simply by hunting. “You have to play Devil's advocate and imagine what conditions were like if they were hunting wild animals on foot,” she says. “The villages had 160 or more houses, so how would they sustain themselves and not deplete the herds immediately?"

  Levine, on the other hand, makes exactly the same argument against domestication. How, she asks, could the villagers graze that many horses nearby without depleting the grasslands?

  "There is a tendency among people who study horse bones to say there are lots of horses in this site, [so] that means they're domesticated,” she says. “But all it means is that lots of horses died and the bones were brought there.” In fact, she says, if you go to more recent sites where horses were known to be domesticated, you don't tend to find such large numbers of bones. “When you find large numbers, that tends to be an indirect indication that they're probably wild,” she argues.

  * * * *

  Indirect Evidence

  One might think it would be easy to figure out if the villagers were raising horses for slaughter, rather than hunting them. After all, domestic horses need equipment such as bridles, lead ropes, and hobbles.

  Unfortunately, all of these would have been made from leather thongs, which would long ago have rotted away.

  "Organic materials such as leather and wood are only very rarely recoverable from the archaeological record,” Levine writes on her web site. “Moreover, not only is it possible to ride a horse without the use of a saddle or bridle, but also, during the early stages of horse domestication, it is likely that they were usually ridden that way."

  Olsen concurs. If you look at classical Greek statues of people on horseback, she says, “they don't have saddles, horseshoes, or stirrups. And that's in 400 B.C."

  The earliest surviving pieces of horse tack were probably “cheekpieces” from bridles. These are fasteners used to help tie together the various thongs of the bridle, near the horse's cheek. Some archaeologists think that odd pieces of worked antler found at Dereivka are cheekpieces, but the artifacts are sufficiently nondescript that Levine dismisses any such identification as wishful thinking. They could be virtually anything, she says.

  The earliest unambiguous evidence of horse domestication doesn't come from much before 2000 B.C. From that era, archaeologists have found lots of clearly recognizable cheekpieces, as well as two-wheeled vehicles that look like chariots, buried not only with their wealthy human owners, but with the horses that presumably pulled them.

  Chariots, however, are an advanced technology. By the time they appeared, Olsen says, horse domestication is “a done deal. You know you're missing the boat."

  Levine concurs. Horses didn't instantly go from being wild to being buried in graves with chariots. “They have to have been domesticated at that stage for some period of time,” she says.

  With other domestic animals, like dogs and cats, one way to look for traces of domestication is in bone-structure changes resulting from domestic breeding. After all, a modern Chihuahua doesn't look much like the wolflike dogs that were its distant ancestors. But horse skeletons don't start to show much sign of this prior to 1200 B.C. “It's not until late that you start to see good evidence for formal breeds,” Olsen says.

  Another approach is by looking at ancient horse teeth for signs of bit wear or at the skeletons of aging horses for abnormalities associated with being ridden or worked in other ways.

  Unfortunately, such evidence is hard to find. Worse, says Levine, the studies are conducted by archaeologists, not veterinarians, and tend not to be rigorous enough to rule out alternative explanations. “They're interesting,” she says, “but I don't think they're very conclusive.” Lab tests are being planned, she adds, to find out exactly what type of pressure bareback riding places on a horse's spine, in an effort to better determine the kinds of bone abnormalities to look for in the Botai and Dereivka horses. “The study many not be conclusive, but it's worth giving a try,” she says.

  Levine herself has studied Botai horse bones for signs of abnormal stresses. But she found nothing. “And I looked for it,” she says. “I looked quite hard."

  "It's frustrating,” Olsen admits. “At the same time it's really fun: a great detective story."

  Currently, she is pursuing her ancient “cold case” at the Botai village of Krasnyi Yar, where her team has discovered a circular array of ancient postholes that looks suspiciously like a corral.

  That discovery is itself an example of modern archaeology in action. Rather than digging up wide swaths of land, archaeologists can now conduct surveys with ground-penetrating radar and other instruments designed to find subtle variations in the soil's electrical resistivity and magnetic properties. The techniques, collectively referred to as geophysical archaeology, have been used to survey everything from Roman bathhouses, Viking longhouses, and Native American burial mounds to German bunkers destroyed in the D-Day invasion of Normandy.

  At Krasnyi Yar, these techniques revealed 54 pit houses and dozens of postholes. Although the postholes had long ago refilled with dirt, they were visible to the imaging techniques because the fill has a different geophysical signature than the surrounding soil.

  It was these postholes that formed the suspicious corral-like arrangements.

  Olsen was thrilled. She believes that the best way to figure out how the ancients raised their horses is by watching how modern cultures do so in similar circumstances. In 1944, the Russians produced a golden opportunity for this by forcing the horse-herding Kazakhs onto communes: year-round villages not all that different from those inhabited by the Botai.

  "What they do is probably analogous to what they did in ancient Kazakhstan,” Olsen says.

  And what do the modern villagers do? They corral the horses near the villages at night, then take them out to pasture during the day. To do that, you need corrals: just like those found in Krasnyi Yar.

  * * * *

  Dung Heap

  Finding the circular structures was exciting enough. But then the scientists had the brainstorm of looking at the paddock soil for traces of ancient horse manure.

  What they found were phosphates, which are one of the primary nutrients contained in animal manure. At a 2006 meeting of the Geological Society of America, Andrew Stiff, a graduate student with the project, reported that phosphate levels in soil samples taken from within one of the paddocks were ten times higher than those in the adjacent soil.

  High phosphate levels, however, can also be created by cooking fires. To rule that out, the researchers examined another mineral, potassium, which should also have been elevated if hearth fires had been the cause. It wasn't, indicating that the find indeed represents manure.

  Phosphate isn't the only nutrient contained in manure. Manure is also high in nitrates—and these were not elevated within the paddock. But the absence of nitrates isn't actually bad news, says Rosemary Capo, a professor at the University of Pittsburgh who is also a member of the team. That's because nitrates easily leach out of soil in rainstorms or are decomposed by bacteria. Phosphates can remain for millennia.

  Thus, the lack of nitrates indicates that the phosphates aren't recent contaminants from a later corral built on the same site. “It suggests we've got old stuff,” Capo says.

  Other archaeological evidence indicates that the horses were raised in the village ra
ther than being hunted in the surrounding wildlands.

  One line of evidence comes from the fact that complete horse skeletons, including skulls and vertebrae, are found in the villages. Hunters, Olsen argues, wouldn't have bothered to bring back these heavy, useless bones. “We call it the ‘schlep effect,'” she says. Instead, they would have butchered their kills in the field and carried back only the parts they needed.

  Furthermore, the archaeologists haven't found many arrowheads at the site, something that should have been plentiful in a hunting culture. And when the scientists used the latest analytical tests to check the arrowheads for ancient blood residues, Olsen says, what blood they found was human.

  Also revealing are the ages of the animals that were slaughtered. “Between 30 and 50 percent were killed young, which indicates culling,” Olsen says. “That's standard in horse domestication."

  Levine has a different interpretation. The horses, she says, appear to have died at ages roughly proportional to what would be found in a living herd, “as if a catastrophe took down the whole herd at once. This is typical of random hunting or herd driving [in the hunt].... If you're raising them for meat, you kill them around age three or four."

  Perhaps, she says, the circular structure was a holding pen for wild animals, corralled for subsequent slaughter. “American Indians used to chase [wild] horses into a corral,” she says, although she notes that doing so in the middle of a village “might have been tricky."

  Or perhaps the corral was used for a few animals, which, like Khan's foal, were captured wild, then tamed. Among the vast numbers of horse bones found in the villages, it would be difficult to distinguish a few tame horses from thousands of wild ones.

  Similar concerns have been raised about the horse bones at Dereivka. There, Levine says, the most common age was seven to eight years. “That's not a time when you would butcher animals for meat,” she says. But if Dereivka's hunters were selectively stalking wild animals in their prime, that's exactly the type of age distribution you might expect.