Shhhh… Danger is Out There

Imagine yourself having a conversation with a friend, and he starts yawning. You think, “My friend is getting bored!” Immediately, you try to be more enthusiastic or … you shorten the conversation. Now imagine a bird in the wild that suddenly hears an alarm call from another bird. What does he do? Most likely, his reaction will be to quickly escape to a safe place. These types of situations, where one animal (including humans) uses the behavior of others to guide his or her own behavior, are constantly happening in our daily lives. Importantly, these behaviors provide a number of advantages that are crucial for survival, like protection against threats. But how do the defense behaviors displayed by one individual who directly detects a threat influence the defense behaviors of others who are unaware of it? And what kind of signals are being used? This is exactly what we are tackling here! And we found out that an important cue is … silence!