Solving a mystery of mammoth proportions
SMU archaeologist David Meltzer talks about a study that found dwindling freshwater sealed the demise of the St. Paul woolly mammoths, and could still pose a threat today.
By Rachel Nuwer
Until recently, Alaska's St. Paul Island was home to a mystery of mammoth proportions. Today the largest animals living on this 42-square mile speck of earth are a few reindeer, but once, St. Paul was woolly mammoth territory. For more than 4,000 years after the mainland mammoths of Asia and North American were wiped out by environmental change and human hunting, this barren turf served as one of the species’ last holdouts.
Only one group of mammoths lived longer than those of St. Paul: the mammoths of Wrangel Island, a 2,900-square mile island located in the Arctic Ocean, which managed to survive until about 4,000 years ago. In this case, scientists suspect we played a hand in the tenacious beasts’ demise. Archaeological evidence suggests that human hunters helped pushed already vulnerable populations over the edge.
But the mammoths of St. Paul never encountered humans, meaning they were shielded from one of the main destructive forces that likely killed their kin. So how did they meet their final end some 5,600 years ago?
Scientists finally think they have the answer. This week, an interdisciplinary team of researchers reported in Proceedings of the National Academy of Sciences that the mammoths essentially died of thirst. Using mammoth remains and radiocarbon dating, researchers found that dwindling freshwater due to climate change caused populations to dry up. Their results—which also show that the St. Paul mammoths persisted for longer than originally thought, until about 5,600 years ago—pinpoints a specific mechanism that may threaten other coastal and island populations facing climate change today.
Scientists had known previously that climate change must have played a role in the St. Paul mammoth extinction, but they had few clues as to the specifics. “This is an excellent piece of research, well-evidenced and well-argued,” says David Meltzer, an archaeologist at Southern Methodist University who was not involved in the study. “It’s just the sort of species- and region-specific work that needs to be done to fully understand the causes of extinction for this and other animals in the past.”