Desert dreams: seeking the secret mammals of the salt pans

Natural History, Nov, 2003 by Michael A. Mares

My story might have ended here, if I had not been so persistent in convincing my colleagues to try our luck again. That was how, during our year 2000 field season, we had come to the Salinas Grandes, to begin a survey of that 3,200-square-mile area within the thorn forest of central Argentina known as the Gran Chaco. And so, after my anxiety dream about losing a trapped rodent, I was up at first light to check my Conibear traps. As I approached the end of the trapline, I still had caught nothing. Only two traps remained. Then I saw it. The next-to-the-last trap held an animal--a viscacha rat, unlike any I had ever seen. My nightmare notwithstanding, no predator had robbed me of it while I slept!

In the past, we had saved something special to celebrate the discovery of a new species. Usually it was a bottle of champagne or fine wine, but even a can of hearts of palm would suffice. For this trip I had splurged on a bottle of exceptionally good Argentine wine, which I packed with care and kept from freezing or overheating. In the several weeks we had been on the road, the rest of our wine supply had been depleted, but I had not allowed anyone to open this special bottle. "If you want to drink the wine, you have to catch the mammal," I would say.

As I returned to camp in the cold light of dawn, I hid the rodent behind my back, hanging it from my belt. Janet was already up, making coffee. I put on a dejected look. "Catch anything?" she asked. "Nothing" I said. Ruben and Monica emerged from their respective tents. "Nothing?" they asked. "Nothing" I said. The sun was peeking above the horizon, and the aroma of coffee and salt mingled in the damp air. I began to rum mage through the food boxes.

"What are you looking for?" Janet and Monica asked, knowing I can never find anything around camp. "I'm looking for that bottle of wine," I said. Everyone stopped and looked at me. They knew I had caught an animal, and that it had to be new to science: it would become a type specimen, the specimen that is needed for the first scientific description of any new species or genus.

"Get the wine!" I said.

We named the new genus Salinoctomys, "the octodontid rodent of the salt flat." The species name, loschalchalerosorum, honors the great Argentine folklore group, Los Chalchaleros, whose songs my crews had sung during thirty years of field research across Argentina. The musicians had announced they would retire in 2001, after singing together for fifty-two years. We felt that they had accompanied us on every trip; we even joked that some of their songs could be called "type locality" songs, because their lyrics mentioned so many places our field crews had collected type specimens. It seemed the most appropriate and permanent way for us to thank the musicians for all the enjoyment their music had given us.

We celebrated our good fortune by drinking that wonderful bottle of wine, but the joy of discovery was tinged with a hint of melancholy. Such a moment would likely never be repeated. We planned to explore other isolated valleys and equally isolated mountaintops--habitat islands at high and low elevations, each as ecologically distant from the others as the islands in a Pacific archipelago--but we doubted we would ever encounter such a pair of distinctively new animals again, much less deduce their existence beforehand using only inferences about the habitat.