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The Rat's Tale
For Louise Emmons, Discovering a New Species Is All in a Life's Work

By Ann Gerhart
Washington Post Staff Writer
Wednesday, March 29, 2000; Page C01

The giant rat was already dead when Louise Emmons found it.

She had been hunting for just such an oddity in the frosty Peruvian cloud forest, but a weasel had nabbed it first, with a cunning bite through the head.

The rat was still warm, and she loved it immediately, although love is the kind of imprecise word that a rigorous scientist like Emmons would scorn.

"It was sort of cuddly," she said.

What truly thrilled the field biologist was the recognition that she had discovered--there amid the forbidding, uninhabited mountains--not just a new species of tree rat, but a whole new genus. Later, she learned her rodent was a relative of the mysterious Incan tomb rats whose bones lay alongside human remains in the ancient city of Machu Picchu in Peru.

"I got lucky," said Emmons.

This is a characteristically modest self-appraisal. Luck like that is born of 30 years of obsessive patience and passionate focus, aching hours spent watching and waiting.

A Smithsonian-affiliated researcher, Emmons at 56 is one of the world's most respected experts on tropical forest mammals. Throw that superlative at her, in her crowded cubicle at the National Museum of Natural History, and she studies her fingernails, then demurs.

"She would be ashamed to claim that," said Robin Foster, a botanist at the Field Museum in Chicago who has been on several expeditions with Emmons. "But she has worked on all the continents, and she has the broadest experiences of anybody I know."

For the past 10 years, between doing her own research, Emmons, who lives in Falls Church, has tramped the world for the D.C.-based environmental group Conservation International, part of a team of biological guerrillas charged with cataloguing the species living in some of the most remote locales.

Emmons and her colleagues helicopter into a region, set up subsistence camps, eat rice and lentils for days, slog through muck and brush, and emerge after a few weeks with a quick-and-dirty inventory of flora and fauna. This data aids advocates seeking to preserve ecosystems and stave off oil and foresting conglomerates. The team's work in northern Bolivia led to the creation of the Madidi National Park.

It's dangerous work. Since CI founded its Rapid Assessment Program 10 years ago, three noted scientists have died, two in a plane crash in Ecuador and one in a boat accident in Peru. Louise Emmons has caught bubonic plague from the rodents in Borneo and a potentially fatal parasitic infection from the flies in Peru. Working alone in the deep night gloom of the forest, looking for her nocturnal creatures, she's been stalked by wild cats.

"You have to be driven to do it," said Emmons. "It is very hard. It seems glamorous to an outsider because you travel to all these exotic places. But it's day after day in the mud and rain and the mosquitoes, collecting the same data over and over."

Still, she says, "It's never dull. You never know when you're going to meet a jaguar."

Or find a new rat.

The rat is huge, way bigger than the snarling, skulking rodents that hug the dumpsters of Adams-Morgan. It's about a foot long from snout to rump, and has almost eight inches of thick, furry tail. It has prominent white fangs for shredding plant life. It has 18 sharp claws for climbing trees, four on each front foot, five on each of the back. ("Animals lose digits when they adapt for running," explained Emmons.) It has fetching, almost cartoonlike long whiskers and an endearing white stripe running up its head, which contrasts handsomely with its dove-gray fur.

And it may be as shy as Emmons herself, since it had revealed itself to no scientist until that day in 1997 when she happened upon it on the trail in the Vilcabamba, an area of mountains in south central Peru, between Andean peaks and the Amazon river basin.

There are about 5,000 known species of mammals on Earth, and researchers are finding more at the rate of about 14 a year, which far exceeds the extinction rate of about 120 species over the past 500 years, said Emmons. But it's rare to find such a big one as Cuscomys ashaninka, which Emmons named to denote the town of Cusco, Peru, and to honor the Ashaninka people who live nearby at lower elevations. And it's ever rarer to discover a new genus--a entire branch on the family tree of rodents.

At first, Emmons thought the tree rat might be a porcupine. "But the minute I bent down to pick it up, I knew it was something entirely different," she said.

"She carried it back into camp in her arms, and she was very excited," said Monica Romo, a bat expert from Peru who had volunteered to study with Emmons on the trip. "She does not jump up and down--she is not expressive like that--but we all knew we had never seen something like that."

And the scientists were hungry with hope. At the camp, nearly 10,000 feet into the sky, they were cold and wet all the time. When they slept at all, it was in tents pitched in standing water and multiplying moss. "We were waiting, waiting to find something new," she said.

In her makeshift laboratory in the biologists' camp, Emmons skinned her rat very carefully, stuffed the skin with cotton and put it in a box with mothballs. The bones were cleaned and dried; the remainder of the rat went into a vat filled with preservative. (Now that the studying is over, the giant rat, carefully stuffed and mounted, resides in Peru's national museum in Lima.)

Back in the States, Emmons speculated that her tree rat might be related to rodents whose bones were found in 16th-century Incan tombs. She began the long and painstaking process necessary for scientific certitude.

The rodents and other mammals had been placed with the dead Incans into the graves, anthropologists determined in 1916 when they dug up the graves at Machu Picchu in Peru. But the biologist on that expedition could not find any similar rats living in the wilds of Peru and concluded they were extinct.

After hours of careful examination of the cranial structure of her giant tree rat, Emmons went to Yale University's Peabody Museum and compared them with the skulls of the rats exhumed from the tombs. She determined that the tomb rats, Abrocoma oblativa, and the Cuscomys belong in the same genus. And she suspects that both species are thriving in the mountains of Peru.

"There's no reason for them to be extinct," Emmons said of the tomb rats. "There hasn't been anything that happened in the last 500 years. [The area is] steep, and hard to get into. I think they have just been overlooked, although it's speculation until we find one."

Her discovery may shed some light on a mystery that has puzzled anthropologists. Why did the Incans bury rats with humans? In a recently published paper, Emmons writes: "Because Cuscomys ashaninka is so large and attractive, the question arises whether C. oblativus may have been kept as a pet, or even domesticated for food or amusement. One complete animal had been placed in a ceramic pot beside the human body."

Like others with a single-minded passion, like artists or nuns, Louise Emmons sees the world quite differently from the general population.

She is most fond of rats and quick to defend against their poor reputation. For a species, "success is measured in population and diversity," she said. "And as the largest order of mammals, rats are very successful. They have many species worldwide, and they can occupy hundreds of ecological niches. Some are very specialized; they eat only earthworms. So they're very flexible."

Emmons was born this way--fascinated with rats, curious about squirrels, absorbed in the study of critters, said her older sister, Julia Emmons, who runs the Atlanta Track Club and is on the city council there. Their father, Arthur B. Emmons, was a diplomat and a famed mountain climber. Childhood was one long, exuberant trek--Montevideo, Uruguay, Spain, Australia.

"I was a nature girl, a tomboy," said Emmons, "and I had a very good teacher in high school, who turned me on to biology."

"From teeny-tiny babyhood on, she had this total laser-beam focus," said Julia Emmons. "It was not a learned quality. It was her. She was solitary; not lonely, but solitary. She would pick things up and look at them intently. When we lived on Macomb Street [in Northwest Washington], we had a little back yard. I remember sitting with her, and the squirrels were running around in the trees. She told me what they were saying to each other, how they twitched their noses and greeted each other. Now, I had never really looked at a squirrel in my life."

Louise Emmons was just as interested in English, and she majored in it at Sarah Lawrence College. While she has taken up ocean kayaking, reading literary fiction remains her chief hobby. Fluent in Spanish and French and "passable in Malay," she reads French literature--in French.

With a PhD in neurobiology and behavior from Cornell and authorship of many scientific papers, Emmons has the academic credentials to grease a tenure track. "The faculty rat race turned me off a bit. It's the reason I'm an independent researcher," she said. So she lives from grant to grant, eking out a living. "All of us [field biologists] are as poor as church mice," she said. "It doesn't really matter."

Her life remains a solitary one. Divorced, childless, Emmons's place in Virginia is mostly an address. She spent seven years on a houseboat in the Potomac. "I loved it," she said, "but a boat can sink, with all your books on it."

Home is in the field. Her stamina is legendary.

"She'll follow jaguars all night, tracking their radio collars. Or they'll follow her, and she'll just keep going, knowing that at any time, they could attack her," said Foster, the botanist. "I don't know anybody as tough as she is. The rest of us are candy-asses by comparison."

A small woman with a soft step, Emmons has perfected the art of walking very slowly through the night, say those who have accompanied her. She stops, listens, takes three more steps, stops, listens again. What she hears becomes the staple of scientific texts or, more rarely, the lyricism of a nature journal.

She once described the rain forest in Orion Nature Quarterly: "You can stand anywhere and be surrounded by hundreds of organisms that are all doing something, going about their living in countless interactions--ants carrying leaves, birds dancing, bats singing, giant blue wasps wrestling with giant tarantulas, caterpillars pretending they are bird droppings, and so on."

Her own meticulous field guide, "Neotropical Rainforest Mammals," has become indispensable for biologists in South America.

The more obscure and obstreperous the animal, the more Emmons seems to enjoy it. Her specialty is the tree shrew family, a collection of 16 species of tiny mouselike creatures--"all neurotic," Emmons once described them.

"They are so fast, you hardly see anything more than a flash. And from these little glimpses, she could detect so much," said nature photographer Frans Lanting, who watched her watching the shrews in Borneo.

"Now, the African brush-tailed porcupine--they were very difficult to work with. They are very hard to catch and put radio collars on," said Emmons. "I had some in a big enclosure, and I was trying to see their behavior and record their vocalization," and she is recalling yet another expedition, and the field work seems to be pulling at her again, out of the drab cubicle deep in the museum bowels, out of the ceaseless cycle of political Washington, drawing her back to the white fog of the Peruvian cloud forest, where the tomb rat may live with the giant rat, the dwarf deer, the rare frogs and the startling orchids.

"I would like to go back to this place," Emmons said. "We've only started to find what's up there."

© Copyright 2000 The Washington Post Company

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