纪录片《我们的地球》 第264期 壮丽山脉(09)（在线收听）

There are now around 30 bears in this one valley.

这个山谷中大约有三十只熊。

As they rub, each leaves an individual and recognisable scent.

每只熊摩擦时都会留下易于辨认的独特气味。

So the tree soon carries a list of who's around,

所以树上很快会留有附近灰熊的气味，

which might help individuals to avoid a fight.

或许可以避免个体之间的争斗。

To best spread their scent, they really have to put their back into it.

为了更好地散布自己的气味，他们得用后背好好地蹭一蹭。

But summer is short. Itches satisfactorily scratched, it's time to eat.

但是夏天很短暂。痒痒挠满意之后，是时候该进食了。

In a couple of months, they will have to return to their dens to hibernate,

几个月后，他们就要回自己的窝里冬眠，

so now they must put on as much weight as they can.

所以现在必须尽可能地增重。

Winter in the mountains returns fast and hits hard.

山里的冬天来得迅猛。

Temperatures in the Rockies will drop to -54 degrees,

落基山脉地区的温度会降至零下54度，

so cold that moisture in the air freezes into tiny crystals called diamond dust.

以至于空气中的水分会直接凝结成冰晶，俗称钻石尘。