摘要
语篇导读 因为人类活动导致自然界环境的变化，狮子、老虎等许多哺乳动物为了避免与人类接触，可能会减少活动或迁移到偏远地方，或通过夜间不眠的方式警惕可能受到的袭击，并且减少觅食的时间。
Lions, tigers and other mammals are staying awake at night to avoid hu- man beings, a new study finds. Scientists have long known that human activities can lead to changes in nature. Many mammals may move around less or travel to distant places to avoid contact with people. By being awake at night, mammals can also be on guard against possible attackers and spend less time looking for food.
