Escritura integrada TOEFL

📖 Texto de lectura

The extinction of the woolly mammoth has long been attributed to climate change at the end of the last Ice Age. However, a growing body of evidence suggests that human hunting was the primary driver. First, archaeological sites across North America and Eurasia show a clear temporal overlap between the arrival of human hunters and the decline of mammoth populations. For example, at the Clovis sites in North America, mammoth bones have been found alongside spear points, indicating active hunting. Second, mammoths were highly vulnerable to predation due to their slow reproductive rates. A female mammoth gave birth only once every five to seven years, and calves required long parental care, making population recovery slow even under moderate hunting pressure. Third, the climate hypothesis fails to explain why mammoths survived previous interglacial warm periods, such as the Eemian, which were warmer than the Holocene. If climate alone were responsible, mammoths would have gone extinct then. Instead, the unique combination of efficient human hunters and the mammoths' life history traits tipped the balance, leading to their rapid disappearance.

🎧 Conferencia de audio

The lecture challenges the idea that humans were the main cause of mammoth extinction. While the reading cites archaeological evidence, that evidence is actually sparse and inconclusive. Many of the so-called hunting sites show cut marks that could have been made by scavenging after natural death, not by active hunting. In fact, at several Clovis sites, the bones show no signs of butchering, and the associated spear points might have been used for self-defense or other purposes. Furthermore, the argument about slow reproduction is misleading. During the late Pleistocene, mammoth populations were already stressed by habitat fragmentation due to climate shifts, which reduced their genetic diversity and made them more susceptible to diseases and environmental changes. Human hunting, even if it occurred, was likely a minor additional stress. Finally, the reading overlooks a critical fact: the Eemian interglacial was not directly comparable to the Holocene because during the Eemian, the mammoths' range remained vast and connected, whereas at the end of the Pleistocene, rising sea levels and advancing forests shrank their habitat drastically. Thus, the real culprit was not human hunters but the rapid loss of suitable grassland environments, which the mammoths could not survive regardless of human activity.