Samuel Taylor, director of the Carnegie Museum of Natural History, calls Sandra Olsen, his curator of anthropology, "probably the most prominent woman in the world in science."

An exaggeration? Maybe, but probably not -- at least not when it comes to the fields of science studying the agricultural origins of man and especially not since publication earlier this month of the article the 56-year-old Mars resident co-authored on that very subject.

"The Earliest Horse Harnessing and Milking," published in the academic journal Science, moves up by about 500 years -- to about 5,500 years ago, or 3,500 B.C. -- the earliest known domestication of horses, by the Botai culture in what is now northern Kazakhstan. The evidence comes from archaeological digs of ancient villages directed by Dr. Olsen since 1993.

Earlier generations of scientists had believed horse domestication occurred about 4,000 B.C., but that eventually was discredited, leaving the question open for fascinated horse-lover Dr. Olsen and other interested zooarchaeologists to pursue and, it appears, to answer.

"They were all buzzing about Sandi Olsen's work," said the Smithsonian Institution's Melinda Zeder of a recent seminar in Mexico's Yucatan province that "involved archaeobotanists, archaeozoologists and archaeologists from all over the world studying agricultural origins in many different world regions.

"The reason her work is so interesting ... [is] it's a great example of the need to look at multiple lines of evidence for domestication and that our tendency to look for a single morphological marker in body size or plant form to mark domestication simply can't be justified. We have to look more broadly," added Dr. Zeder. She, like Dr. Olsen, is a zooarchaeologist whose official title at the Smithsonian is director, Archaeobiology Program, National Museum of Natural History.

The Science article, which includes co-authors from the United Kingdom, France, Russia and Kazakhstan in addition to Dr. Olsen, cites three new pieces of evidence that the Botai people are the oldest known culture to have domesticated horses:

• The horse cannon bones found at the sites were more slender than those of wild horses and therefore more similar to those of equines domesticated in later eras;

• Markings on the teeth of horse skulls indicated they had been bridled; and

• Isotope data from Botai pottery fragments identified fat as being from horse's milk, which is leaner than that of cow's milk and more like "1 percent," Dr. Olsen said. "That's a smoking gun," she added, "and the reason is, you can't imagine milking a wild mare."

But over the months Dr. Olsen spent with crews sifting slowly and meticulously through the dirt for bones and pottery shards and tools, she said she "had amassed a long list of things" supporting her theory about the Botai, whose main protein was horse meat.

The uncovering of a corral, she said, "was another smoking gun, and I had no chance to publish that one properly," though it is in the academic purview through earlier papers and presentations.

"We have [horse] manure used in roofing and large sedentary villages," Dr. Olsen added, "so now it becomes very hard to say they were hunting wild horses and nothing else and surviving with 400 to 1,000 people [living] year-round in a permanent village, because they would have quickly depleted herds and become nomadic."

Still another find, "secondary evidence" said Dr. Olsen, were numerous tools apparently used to make rawhide leather strips for bridles, lassos and hobbles.

"We also had one burial site with four humans and 14 horses that were sacrificed, a high number if they were wild animals."

And, finally, excavators found the kinds of big bones that would have been left behind if the horses had been killed a long way from the village.

"Her work was multiple lines of circumstantial evidence that horses were domesticated but she didn't have the smoking gun yet," Dr. Zeder said, "and to my mind, the milk was the smoking gun. That really seals it."

Dr. Olsen's work at the Kazakhstan sites, originally discovered by Kazakh scientists in the mid-1980s, was sparked when colleague David Anthony of Hartwick College in Oneonta, N.Y., invited her to work on his excavation in Russia. They made a side trip to see the Kazakh excavations and, she said, "I never got back to David's site. There was a question looming there and I had to go after that. I had to answer the question of horse domestication."

She also has done archaeological digs in France, Cyprus, Greece, the American Southwest and Kansas.

Though she grew up in Wichita, Kan., around aviation, Dr. Olsen says she fell in love with museums and archaeology as a third-grader and paleontology even earlier. Those loves blossomed when she visited the Denver Museum of Natural History [now the Denver Museum of Nature and Science] each summer with her parents. Meanwhile, she learned about modern horses visiting country cousins, including a red-haired Annie Oakley type who could shoot a rattlesnake from a full gallop. "She kind of inspired me," Dr. Olsen said.

She pursued her academic passions with bachelor's and master's degrees in anthropology from Wichita State University and the University of Arizona, respectively, and a doctorate from the Institute of Archaeology at the University of London.

"What got me started on horses in my career was Solutré" an ancient communal hunting kill site in France, once thought to be where they were driven off a cliff to their deaths. Dr. Olsen's research discredited that. Rather, she proved the horses were herded into a natural corral and butchered.

That equine research was just an appetizer to Dr. Olsen's main course of study at Kazakhstan, where the work didn't come easily.

"I started 18 months after the breakup of the Soviet Union [of which Kazakhstan was a republic]," said Dr. Olsen, "Even pens and bags and notebooks had to be brought from America," she said.

"We were always running out of gasoline. There are no filling stations anyway. We had cans of gas in the vehicles."

One time a man flagged their gas can-filled vehicle over. Good thing he did: three of four lug nuts on a wheel were missing and the axle was broken.

"One year, probably 1995, we had no bread because they couldn't get gas to power the harvester so there was no grain and bread is a staple there," Dr. Olsen said.

"Some things were always available -- vodka and chocolate and cigarettes. Those were always available and, surprisingly, always gladiolas." Urban-dwelling Kazakhs grow the latter on the little quarter-acre dachas given to them by the government.

The excavation work itself is painstaking and demanding -- Dr. Olsen says she can't ride horses much anymore because she has "archaeologist's back." The climate of Kazakhstan is harsh, particularly for someone camping. But Dr. Olsen is not complaining. Rather her eloquent reminiscences ring with romance and lyricism.

"Archaeology is kind of like 'CSI' with a very cold case," she said. "It's detective work. That's the way I view it: questions not answered. You pick one that excites you, that you can devote your time and energy to and go for it."

The rolling steppes of Kazakhstan remind her of Kansas, right down to the threat of tornadoes. "There's nothing better than camping out in Kazakhstan, watching the sunset, watching storms come from the west. We had [funnel clouds] come through the site. It's very windy, extrarordinarily windy. We get hail. ... Sleeping in a tent when it's very windy and lightning is a great experience," Dr. Olsen said.

"It is a little bit scary. We had a lot of grass fires one year, dry lightning. The heat lightning lights the whole sky. These bolts were hitting the grasses. Then we had a plague of locusts, followed by one of spiders. ...

"The other thing in Russia and Kazakhstan is ball lightning. It is balls of light that float around. They can come into the house and catch the house on fire. ...

"I camped out a lot in childhood. There's most severe weather there too, so I was conditioned in a way."

And then there is the sheer physical beautiful of the undulating forest steppes in Kazakhstan. "The vegetation looks like a sage velvet." she said. "There are gently rolling hills with a velvety cast to them. The forest is pine and birch and there are all kinds of wildflowers, beautiful wildflowers, lots of thistle." There are wild, safe-to-eat mushrooms, raspberries, strawberries and currants, too.

Dr. Zeder noted wryly: "She clearly enjoys that element of it, the romance of field work, the interaction with indigenous people. She's got the whole package of hard science as well as wanderlust and excitement of our field."

And Dr. Olsen, who is married to Chris Beard, the head of Vertebrate Paleontology at the Carnegie, can translate that "whole package" into entertaining, funny, witty stories when she comes home.

"Ask her sometime about being a diplomat for the organization and for her own work and being invited into a Kazakhstan home and being offered a fermented cup of mare's milk," Dr. Taylor said. "Fermented mare's milk is an acquired taste. It's not the kind of thing you'd pull out to relax with after work."

But it is the kind of thing Dr. Olsen would try to enrich her knowledge of the Kazakh culture.

Once she got interested in solving the question of when horses were domesticated, she set out to learn everything she could about horses, period.

The late Mary Littauer, of Syosset, N.Y., a self-taught, independently wealthy woman who was married to a former Russian cavalry officer and who had an equine library of 17,000 volumes, became Dr. Olsen's mentor for all things horses outside the domestication question. Mrs. Littauer taught her, among other things, about horses in antiquity, the development of packs and the history of bridles and saddles and harness.

"I started broadening my scope, with questions for equestrians, veterinarians, people in animal science who knew more about nutrition than I did," Dr. Olsen said. "I'm honest. I came through the back door."

But she made it to the front of the auditorium stage. When it came time for Ross MacPhee, curator of mammals for the American Museum of Natural History, to put together "The Horse," the traveling exhibition now at the Carnegie, he asked Dr. Olsen to be his co-curator.

"I immediately thought of Sandi; I knew we could work together, and felt sure the show would be brilliant if she were involved. Called that one right!

"I knew I could handle the more technical, biological aspects of the show, but I wanted it to emphasize not only 'how we made horses' (i.e., breeding and like topics), but also 'how horses made us' (i.e., our first animated machine, and how it changed history)," Dr. MacPhee said in an e-mail interview. "That meant I needed, as co-curator, someone who had a wider, culturally oriented perspective on the horse/human relationship."

Dr. MacPhee also called Dr. Olsen "a source of uncommon, interesting ideas," and Dr. Zeder said that "her creativity and willingness to think outside of the box" is the first thing she thinks of when she hears Dr. Olsen's name.

"The best example is her approach to the documentation of the domestication of horses," Dr. Zeder said.

Other animals changed dramatically physically as they were domesticated, but horses, she said, "are a real conundrum. We don't have a good idea of what the wild ancestors looked like ... so [Dr. Olsen] thought long and hard about what that interaction [between horses and humans] would have been and came up with a whole variety of creative tools to look at it ...

"A lot of people would have given up and said, 'Who knows?' " Dr. Zeder said. "Sandi didn't give up and for years kept at this particular topic, thinking of creative ways to overcome obstacles. That may be emblematic of her entire approach to her career and life."

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