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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将面临中暑的威胁
In the full sun, the temperature on the ground soars to 70 degrees.
待到阳光最毒辣之时，地面温度已升高至70℃
By midday, the radiation is so intense they must take shelter.
到了正午，太阳的炙焰迫使它们不得不寻找庇荫处
In the shade, they are shielded from much of the sun's energy
在树荫下，它们虽然避开了太阳的能量
but their body temperature can still rise.
但它们的体温仍在升高
So they lick saliva onto their forearms
所以它们将唾液抹在前臂上
where there is a network of blood vessels close to the surface of the skin,
那里的血管网比较贴近皮肤表层
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
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
The blue areas on the body are the cooler parts.
身上蓝色的部分是较冷的部位
As the saliva dries, it has to be replaced.
唾液干了之后还得重新抹上
And this is a real drain on the kangaroo's body fluids.
袋鼠真正排放出去的体液也就是这些
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
So the kangaroos dig away the warmed topsoil to get at the cooler ground beneath.
于是袋鼠刨去灼烫的表层沙土，贴近下面较冷的地面。
