And while they're up here 它们高悬在洞穴上方时

71. The bats roost high on the walls and ceilings
    这些蝙蝠倒挂在洞壁和天顶上
72. where they're well protected from the outside elements
    它们在此完全不受外界因素的干扰
73. and safe from predators.
    还能躲开天敌
74. And while they're up here
    它们高悬在洞穴上方时
75. the bats produce something very important.
    会产生一种非常重要的东西
76. This hundred metre high mound is made entirely of bat droppings -
    这堆100多米高的东西 全都是蝙蝠的排泄物
77. guano.
    粪便

来自《行星地球 第一季 第四集 Planet Earth S01E04 洞穴》第 74 行