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Any kangaroo out in the open is in serious danger of overheating.
任何一只呆在外面的袋鼠都將面臨中暑的威脅
In the full sun, the temperature on the ground soars to 70 degrees.
待到陽光最毒辣之時，地面溫度已升高至70℃
By midday, the radiation is so intense they must take shelter.
到了正午，太陽的炙焰迫使它們不得不尋找庇蔭處
In the shade, they are shielded from much of the sun's energy
在樹蔭下，它們雖然避開了太陽的能量
but their body temperature can still rise.
但它們的體溫仍在升高
So they lick saliva onto their forearms
所以它們將唾液抹在前臂上
where there is a network of blood vessels close to the surface of the skin,
那里的血管網比較貼近皮膚表層
and as the saliva evaporates, their blood is cooled.
因此，當唾液蒸發時，血液也能得到冷卻
This thermal image shows just how effective the process is.
這幅熱影像能證明這種方法非常有效
The blue areas on the body are the cooler parts.
身上藍色的部分是較冷的部位
As the saliva dries, it has to be replaced.
唾液干了之后還得重新抹上
And this is a real drain on the kangaroo's body fluids.
袋鼠真正排放出去的體液也就是這些
Even in the shade, the earth is baking hot.
即使是在樹蔭下，土地照樣被烤得火熱
So the kangaroos dig away the warmed topsoil to get at the cooler ground beneath.
于是袋鼠刨去灼燙的表層沙土，貼近下面較冷的地面。
