Listen to part of a lecture in a biology class. The professor is discussing the behavior of certain birds.
Professor: Today, we're going to talk about a fascinating behavior known as 'anting' observed in some bird species. Anting is when birds deliberately rub ants on their feathers. Some birds even pick up ants and place them under their wings. Why would they do this? There are several theories. One is that the formic acid produced by ants helps control feather mites and other parasites. Another theory suggests that the ants' secretions soothe the skin during molting. But interestingly, some birds don't use live ants; they use other objects like citrus fruits or even burning cigarette butts, which are rich in chemicals. This behavior is called 'passive anting' or 'substitute anting.' Researchers have found that these alternative sources also contain antimicrobial properties. So, it's likely that the primary function is to maintain feather health and reduce the burden of parasites. The exact mechanism is still debated, but the evidence strongly points to a hygienic purpose.
❓ 题目 What is the main purpose of anting behavior according to the professor?