The death of the final mammoths

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A new study analyzing the potential scenarios that may have led to the last population of mammoths, a group on Wrangel Island in the Arctic Ocean that died out 4,000 years ago, going extinct has suggested that a combination of the isolation of the island, extreme weather events, and potentially the expansion of prehistoric humans led to their extinction. The study examined carbon, nitrogen, sulfur, and strontium isotopes from a set of mammoth bones from Northern Siberia, Alaska, the Yukon, and Wrangel Island, with ages ranging from 40,000 to 4,000 years ago, in order to determine wether or not there were possible changes in the mammoth's diet and their habitat that could suggest an environmental disturbance. The study found that the collagen carbon and nitrogen isotope compositions of the bones of the Wrangel Island mammoths did not change as the result of the climate warming, suggesting that they lived in stable living conditions for their species, in contrast to those populations from Siberia and Alaska, which showed significant changes that suggested environmental changes shortly before their extinction. The study also found that there was a difference between the carbonate carbon isotope values of the Wrangel Island and the Siberian populations, suggesting that their diets had different amounts of fats and carbohydrates, suggesting that the Wrangel Island mammoths did not need to rely on their fat stores to survive in a climate that was far milder than that of their fellow populations. Thus, the study suggests that more short-term effects were to blame for the final extinction of the mammoths. For example, the sulfur and strontium isotopes found in the bones suggest that bedrock weathering increased around the time of the extinction, which may have affected the quality of the mammoth's drinking water. Extreme weather, such as an icing event, could have also led to the extinction, as it would cover the ground with a thick layer of ice that would prevent the mammoths from finding enough food to survive. In addition, the study suggests that the arrival of prehistoric humans may also have contributed to the extinction, although the earliest known human artifacts on the island are only known from a few hundred years after the most recent mammoth bone. This study shows that isolated small populations of large animals are at risk of extinction due to extreme environmental influences and human behavior. Here is a link to the paper describing this study.

Paper (open access!): https://www.sciencedirect.com/science/article/pii/S0277379119301398?via%3Dihub