The extinction of the woolly mammoth has long been attributed to human overhunting, but recent evidence suggests that climate change was the primary driver. First, the timing of mammoth extinctions correlates with the end of the last Ice Age, when global temperatures rose sharply. Paleontological records show that mammoth populations declined most rapidly between 15,000 and 10,000 years ago, exactly when forests expanded and grasslands shrank. Second, mammoths were highly specialized grazers, relying on nutrient-rich grasses that thrived in cold, dry steppe environments. As the climate warmed, these grasslands were replaced by mossy tundra and dense forests, depriving mammoths of their primary food source. Third, human hunting pressure was likely too low to cause extinction. Archaeological evidence indicates that human populations in Siberia and North America were sparse, and mammoth kill sites are rare. Even where humans hunted mammoths, they likely took only a small number of animals, similar to modern subsistence hunters who do not drive prey to extinction. Therefore, the woolly mammoth’s demise was a natural consequence of post-Ice Age climate change, not human activity.
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The reading argues that climate change, not human hunting, killed the woolly mammoth. However, this view is flawed. First, while the timing of extinction overlaps with warming, climate shifts alone cannot explain why mammoths survived previous interglacial periods, which were equally warm. For example, the Eemian interglacial, 120,000 years ago, had temperatures similar to today, yet mammoths thrived. This suggests they could adapt to warmer conditions if not overhunted. Second, the dietary argument ignores that mammoths were not strictly restricted to grasses. Isotopic analyses of mammoth bones show they also consumed shrubs and herbs, which were present in forested areas. Thus, habitat change would not have caused starvation. Third, the claim that human hunting was negligible is contradicted by new archaeological finds. In Siberia, several sites show mass kills with stone spear points embedded in mammoth bones, and population models indicate that even low hunting rates can drive slow-reproducing species like mammoths to extinction over several centuries. Therefore, human predation, not climate, was the decisive factor.
📝 写作提示 Summarize the points made in the lecture, being sure to explain how they cast doubt on the specific points made in the reading passage.
