Escritura integrada TOEFL

📖 Texto de lectura

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 their decline correlates with the end of the last Ice Age, when global temperatures rose rapidly. As the climate warmed, the steppe-tundra habitat that mammoths depended on shrank dramatically, replaced by forests and wetlands. This habitat loss would have reduced food availability and fragmented populations, making them more vulnerable to extinction. Second, genetic studies of mammoth remains show a significant loss of genetic diversity before their final disappearance, indicating that populations were already stressed and declining long before humans could have exerted hunting pressure. This bottleneck suggests that environmental factors, not hunting, caused the population crash. Third, archaeological evidence from human settlements shows that mammoth bones were often used for building materials and tools, but these remains are rare compared to other game animals. If humans had hunted mammoths to extinction, we would expect to find many more kill sites and carcasses with butchering marks. Instead, humans likely scavenged mammoths that had already died from natural causes, implying that hunting was not a major factor in their extinction.

🎧 Conferencia de audio

The reading claims that climate change, not human hunting, drove the woolly mammoth to extinction. However, this argument is flawed. First, while habitat change did occur, mammoths were highly adaptable and had survived previous interglacial warm periods. During earlier warm phases, they coexisted with expanding forests by migrating to refuges, such as Arctic islands, where they persisted for thousands of years. The final extinction occurred only after humans arrived on those islands, suggesting that hunting, not climate, was the decisive factor. Second, the genetic diversity loss cited in the reading can be explained by natural population fluctuations, not necessarily climate stress. More importantly, human hunting can also cause genetic bottlenecks, as selective targeting of large individuals reduces population size and diversity. In fact, modern studies of elephants, which are similarly hunted, show rapid genetic declines. Third, the scarcity of mammoth kill sites is not surprising. Humans likely used only the most accessible parts of carcasses, such as tusks and hides, and transported meat to camps, leaving few butchering remains. In contrast, sites with clear evidence of mammoth hunting, such as the Clovis sites in North America, have been found, with projectile points embedded in bones. Thus, the lack of evidence is not evidence of lack of hunting. Overall, the reading underestimates the role of human predation in the mammoth's demise.