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 certain birds. 'Today, we're going to talk about a fascinating behavior known as 'anting,' which is observed in some bird species. Anting involves birds intentionally rubbing ants on their feathers or allowing ants to crawl through their plumage. This behavior has puzzled scientists for years. There are several hypotheses to explain it. One hypothesis suggests that the formic acid secreted by ants acts as an insecticide, helping birds get rid of parasites like mites and lice. Another idea is that the ants help to soothe the birds' skin during molting, when new feathers are growing. A third, more recent theory proposes that anting might be a way for birds to supplement their diet, as they sometimes eat the ants, which are rich in protein. Interestingly, some birds even use other arthropods, like millipedes, which produce toxic secretions, possibly to repel predators. So, the exact function of anting remains unclear, and it might vary among species.'