They appear after rains, 它们在雨后出现

157. This is what they've been heading for...
     这里就是它们的目的地
158. ...A rare water hole.
     一个珍贵的水坑
159. In deserts, most water holes are short lived.
     沙漠里的大部分水坑都转瞬即逝
160. They appear after rains,
     它们在雨后出现
161. but then vanish almost as quickly as they came.
     但以几乎同样的速度消失
162. Animals have come here from many miles around.
     动物长途跋涉来到这里
163. Yet this can be a dangerous place in which to linger.
     但在此地逗留可能会有危险

来自《行星地球 第二季 第四集 Planet Earth S02E04 沙漠》第 160 行