TOEFL統合ライティング

📖 読解文章

The extinction of the woolly mammoth has long been attributed to overhunting by early humans. Proponents of this theory argue that human hunters, armed with advanced tools and cooperative strategies, systematically drove mammoth populations to collapse. First, archaeological sites across Eurasia and North America show a clear correlation between the arrival of human populations and the decline of mammoth remains, suggesting a direct causal link. Second, the mammoth’s slow reproductive rate—with a gestation period of nearly two years and long intervals between births—would have made it highly vulnerable to even modest levels of hunting pressure. Third, the discovery of spear points and butchering sites alongside mammoth bones indicates that humans actively targeted these animals for food and materials, supporting the idea that hunting was a primary driver of their extinction.

🎧 リスニング講義

The lecture challenges the overhunting hypothesis, presenting alternative explanations that better fit the evidence. First, the correlation between human arrival and mammoth decline is not universal; in some regions, mammoths persisted for thousands of years after humans appeared, while in others, they disappeared before human contact. This weakens the causal claim. Second, while the mammoth’s reproductive rate was indeed slow, this alone does not prove hunting was the cause. Climate change at the end of the Pleistocene drastically altered mammoth habitats, shrinking the grasslands they depended on and fragmenting populations. This environmental stress likely reduced fertility and increased calf mortality, making natural decline more plausible than human predation. Third, the presence of spear points and butchered bones does not necessarily indicate sustained hunting. Humans may have scavenged carcasses of animals that died from other causes, or hunted only occasionally. The archaeological record shows no evidence of mass kills or large-scale hunting drives, which would be expected if humans were the primary cause. Thus, the lecture argues that climate-driven habitat loss and other ecological factors, not human overhunting, were the main reasons for the mammoth’s extinction.