Samples of everything from mammoth hair to bone marrow to tiny Pleistocene plants have been taken to laboratories around the world for analysis. Much of the material comes from the original 23-ton block that was airlifted to an ice cave in the town of Khatanga. Many more samples come from hundreds of bones, tusks and other items found during an extensive expedition to Siberia's Taimyr region last summer.
It still isn't clear how complete the Jarkov mammoth's remains are, as the gradual process of defrosting the giant chunk of permafrost continues. Scientists are using hair dryers in a frozen cave to thaw the block, millimeter by millimeter, and collect everything that doesn't melt. Only a small fraction of the block has been revealed, but mammoth bones, hair and other items have been found. It is still possible that meat or even organs lie farther down, but scientists have seen enough to determine that the mammoth is not as unbroken as they had originally hoped.
"No one ever claimed there was a complete, intact mammoth carcass in there," says scientific coordinator Dick Mol of the Netherlands. "Moreover, the project has never been just about a single mammoth; our intent has always been to learn about the animal in its environment, to find out about all the other fauna and flora that existed in the Pleistocene epoch in which it lived."
While no frozen meat has been found in the block, cartilage and tissue samples have been taken from another mammoth carcass out in the tundra. And the team plans to recover the rest of this second mammoth in April.
Biologist Ross MacPhee of the American Museum of Natural History in New York says results from more than 50 radiocarbon dates obtained from mammoth material (as well as remains of other ancient mammals, including horses, musk oxen, moose and even a Pleistocene wolf) indicate that mammoths lived in the Taimyr region for tens of thousands of years. However, during two periods (36,000 to 32,000 and 19,000 to 14,000 years ago), the dating record indicates that mammoths were either extremely rare or absent in places where their bones are most often found, such as lake margins or along riverbanks. Perhaps they moved to the south to get away from adverse conditions, such as the absence of suitable food or catastrophic flooding.
"We know that the mammoths lived through many different climatic periods, warm and cold," says MacPhee. "They were adaptable animals, resilient." MacPhee says this finding may cast some doubt on the prevailing theory that the mammoths died out — roughly 10,000 years ago — due to climate change. MacPhee is looking for evidence to support a counter theory: that a deadly virus introduced by humans killed the mammoth and other mega-fauna at the end of the last ice age.
Meanwhile at the University of Michigan, Daniel Fisher has analyzed material from the Jarkov's tusks, examining isotropic systems and "growth lines." Similar to tree rings, these can reveal seasonal differences in growth and metabolic rates based on diet. He says there are signs the mammoths may have migrated with the seasons, or as conditions changed due to food availability.
Bas van Geel, Jan Peter Gels and Guido van Reenen of the Netherlands have examined pollen, seeds and tiny plants found in the block and in the mammoth's hair. They say the remains point to grassy steppe vegetation and a dry climate, meaning there was probably little snow cover in the winters, unlike the extensive cold and snow of the Taimyr tundra today.
In essence, the giant block and other remains constitute a "slice of life" as it was 20,380 years ago, the age of the Jarkov mammoth as established by radiocarbon dating.
In all, 37 scientists are part of the Jarkov team in what Alexei Tikhonov, Russia's most noted mammoth expert, says is the largest, most extensive effort ever mounted to investigate these giants of the ice age. "Excavations used to be made during the summer thaw, often using water hoses to clear the dirt away from the remains," he says. In the process, much valuable material was lost.
Lifting the block of permafrost clear out of the ground allowed for new levels of scientific study. "For the first time the remains of an extinct mammal as large as a mammoth have been airlifted to a lab for more leisurely study than the Siberian summer usually allows," says geologist Larry Agenbroad of Northern Arizona University. "This is a multifaceted, ongoing project, and I think it only gets better."
