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 decline correlates closely with the rapid warming at the end of the last Ice Age, around 10,000 years ago. As temperatures rose, vast grasslands—the mammoth’s main food source—were replaced by forests and tundra, shrinking their habitat dramatically. Second, genetic studies of fossil remains show a severe population bottleneck occurring before the arrival of large-scale human hunting in many regions. This suggests that climate-induced habitat loss had already weakened the species, making them more vulnerable to extinction. Third, archaeological evidence indicates that early humans primarily hunted smaller, easier prey, such as deer and rabbits, rather than adult mammoths. Few kill sites with mammoth bones have been found, and those that exist are often associated with scavenging rather than active hunting. Therefore, while humans may have delivered a final blow to isolated populations, the overarching cause of woolly mammoth extinction was the dramatic climate shift that destroyed their ecosystem.
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The lecture challenges the argument that climate change alone drove woolly mammoths to extinction. First, while warming did alter habitats, similar warming events had occurred in previous interglacial periods, yet mammoths survived those changes. The key difference in their final extinction was the presence of advanced human hunters, who had not been present during earlier warm periods. Second, the genetic bottleneck mentioned in the reading actually occurred much earlier, around 50,000 years ago, long before the final extinction. Moreover, mammoth populations actually rebounded after that bottleneck, which indicates that climate stress was not permanently fatal. Third, the archaeological evidence is misleading. Recent excavations on Wrangel Island and in Siberia have uncovered numerous mammoth bones with clear cut marks from stone tools, and some sites show evidence of mass kills at water holes. These findings demonstrate that humans did actively hunt mammoths, especially when they were concentrated in shrinking habitats. Thus, the lecture concludes that human predation, not climate, was the decisive factor in the mammoth’s demise.
📝 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.
