托福口语 Task 4

Today, we're going to talk about a fascinating behavior in the animal kingdom called 'biological altruism'—where animals act in ways that benefit others at a cost to themselves. One classic example is the meerkat. In meerkat groups, individuals take turns acting as sentinels, standing on high ground to watch for predators. While on duty, the sentinel is more exposed and cannot forage for food, which increases its risk of being attacked. But this behavior alerts the rest of the group to danger, allowing them to escape. Another example is the vampire bat. After a successful blood meal, a bat will often regurgitate blood to feed a fellow bat that failed to find food. This sharing is costly because the donor loses a meal, but it ensures the survival of its colony members. Importantly, these acts are not random—they tend to occur among related individuals or those who have previously helped each other, which suggests that altruism is reinforced by reciprocity and kin selection. So, the main point is that biological altruism, while seemingly selfless, actually promotes the long-term survival of the group and the altruist's own genes.