托福听力

🎧 听力原文

Listen to part of a lecture in a biology class. The professor is discussing the behavior of a particular bird species. Professor: Today, we're going to talk about the Clark's nutcracker, a bird native to western North America. This bird has an extraordinary ability: it can remember the locations of thousands of hidden seeds for up to nine months. But how does it do this? Recent research has shown that the hippocampus, a brain region involved in spatial memory, is significantly larger in Clark's nutcrackers compared to other birds of similar size. This enlargement allows them to create a mental map of their environment. Interestingly, this ability is not just about memory; it's also about problem-solving. In experiments, these birds have been observed using complex strategies to retrieve seeds, such as remembering which caches have been depleted and avoiding them. However, there is a trade-off: this impressive memory comes at a cost. The energy required to maintain such a large brain area means the birds need to consume more food, especially during the winter. So, while their memory is a remarkable adaptation, it also imposes a significant metabolic burden.