As the vegetation in one place begins to run out 当一个地方的植物即将吃光时
which tell others in the group that they must move on. 提醒蝗群中的其它成员它们应该动身了
Eggs that have remained in the ground for 20 years begin to hatch. 在地下埋藏了20年的虫卵开始孵化
The periods of boom in Death Valley are short. 死亡谷中的花期很短
but these are the short moments that make it possible to live in deserts the year round. 但就是这些短暂的日子使它们 得以全年在沙漠中生活
Elsewhere in Africa elephants drink every day, 非洲其它地方的大象每天都会喝水
This water fell as rain in mountains more than a hundred miles away. 这些水来自100英里之外的山地降雨
It's the sort of behaviour that can make all the difference in a place of serious shortages. 这一举措在这个资源 严重匮乏的地方显得极为重要
Yet all this can change in an instant. 然而所有这一切即刻就将发生改变
In savanah country huge herds of games support prides containing 20 lions or more. 热带大草原的竞争促使鼎盛的 狮群数量达到20只 甚至更多