As the saliva dries it has to be replaced 唾液干了之后还得重新抹上

98. and, as the saliva evaporates, their blood is cooled.
    因此 当唾液蒸发时 血液也能得到冷却
99. This thermal image shows just how effective the process is.
    这幅热影像能证明这种方法非常有效
100. The blue areas on the body are the cooler parts.
     身上蓝色的部分是较冷的部位
101. As the saliva dries it has to be replaced
     唾液干了之后还得重新抹上
102. and this is a real drain on the kangaroo's body fluids.
     袋鼠真正排放出去的体液也就是这些
103. Even in the shade the earth is baking hot
     即使是在树荫下 土地照样被烤得火热
104. so the kangaroos dig away the warmed topsoil
     于是袋鼠刨去灼烫的表层沙土

来自《行星地球 第一季 第五集 Planet Earth S01E05 沙漠》第 101 行