The extinction of the dodo bird in the late 17th century is often attributed to human overhunting by sailors and settlers. However, a more comprehensive view suggests that the primary cause was the introduction of invasive species, particularly rats, pigs, and monkeys, which destroyed dodo nests and competed for food. First, historical records indicate that dodo populations on Mauritius declined rapidly after the arrival of these animals, even before significant hunting pressure occurred. For example, Dutch sailors reported that dodos were easy to catch, yet they also noted that many nests were found empty or destroyed, likely by rats and pigs. Second, the dodo’s ecological niche—ground-nesting and flightless—made it uniquely vulnerable to nest predators. Since dodos evolved without natural ground predators, they had no defensive behaviors against mammals, leading to high egg and chick mortality. Third, the rapid deforestation by settlers for agriculture and timber removed the dodo’s primary food sources, such as fruits and seeds, and destroyed its habitat, making recovery impossible even if hunting had ceased. Thus, while hunting contributed to the dodo’s demise, the introduction of invasive species and habitat loss were the decisive factors.
🎧 听力讲座
🎯 模拟考试环境：先点「播放讲座」听完内容，再作答。听力原文默认隐藏。
The lecture challenges the reading’s claim that invasive species and habitat loss were the primary causes of the dodo’s extinction. Instead, the professor argues that human hunting was the dominant factor. First, the reading overlooks that rats and pigs were not introduced in large numbers until after the dodo had already become rare. Historical records show that early Dutch settlers reported abundant dodos in 1598, but by 1638, when invasive species had become established, dodo numbers had already plummeted due to direct hunting. Second, the reading’s point about nest predation is exaggerated because dodos laid eggs in hidden burrows and showed some protective behaviors, such as mobbing small predators. Moreover, studies of similar flightless birds, like the moa in New Zealand, show that hunting alone can drive extinction even without invasive predators. Third, deforestation was not as extensive as the reading suggests; only coastal areas were cleared, while dodos inhabited the interior forests. In contrast, hunting was relentless and targeted adult birds, which had no natural fear of humans, making them easy to kill. The professor concludes that the rapid extinction timeline aligns more closely with hunting pressure, not the slower effects of invasives or habitat loss.
📝 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.
