托福口语 Task 4

Today, we're going to talk about a fascinating concept in animal behavior called 'safety in numbers.' This idea suggests that animals often gather in large groups not just for social reasons, but primarily to reduce their individual risk of being attacked by predators. The main point is that by being part of a group, each animal increases its chances of survival, even if the group itself might attract more attention. Let me give you two clear examples. First, consider the behavior of schooling fish, like sardines. When a predator such as a tuna approaches, the school doesn't scatter randomly. Instead, they form a tight, swirling mass, often called a bait ball. This confuses the predator because it has so many moving targets. The predator may strike at the edge of the ball, but the odds of catching any single fish are greatly reduced. Each fish benefits because the predator's attention is divided among hundreds of individuals. Second, think about a herd of wildebeest on the African savanna. When lions attack, the herd stampedes. However, individual wildebeest that stay on the outskirts are more vulnerable. Those in the center of the herd are protected by the bodies of others. The lions typically target the weak or isolated ones, so being in the middle greatly reduces an individual's chance of being singled out. So, in both cases, the key is that grouping dilutes the risk for each member.