托福口语 Task 4

Today we're going to talk about a fascinating concept in behavioral ecology called 'alarm calls'—signals animals use to warn others of danger. The main point is that these calls are not just simple reactions; they are sophisticated communication systems shaped by survival needs and social structure. Let me give you two examples. First, consider the vervet monkey. When a predator like an eagle appears, they give a distinct 'eagle call,' which causes all monkeys to look up and hide under bushes. But when a leopard approaches, they use a different 'leopard call,' and the group runs up into trees. This shows that their calls are specific to the type of threat, increasing the group's chances of survival. Second, think about the domestic chicken. When a rooster finds food, he makes a 'food call' to attract hens, but he also makes a different 'alarm call' when a hawk flies overhead. Interestingly, hens respond more strongly to the alarm call if the rooster is a familiar companion, indicating that trust and social bonds influence how signals are received. So, alarm calls are not just automatic; they convey precise information and depend on social relationships.