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Transcript
High in the trees, one mammal gets about without touching the ground: the Siberian squirrel. It can glide.
A furry membrane stretches from its wrists to its ankles. There could hardly be a more efficient way of travelling.
At this time of the year, the female squirrels are not only feeding for themselves. They're also raising families. A disused woodpecker's nest hole protects the young squirrels from the sub-zero temperature. Their mother's precious milk must sustain them throughout the winter.
Five weeks later, the warmth of spring has transformed the forests. It's time for the young squirrels to leave the shelter of their nest. But first flights are somewhat daunting.
One of the youngsters seems keen, and one, not quite so confident. The first climbs up the tree while the other watches. The higher up they go, the further they will glide.
And then … lift-off!
Made it.
But the other seems to have pre-flight nerves. Perhaps he'll try … tomorrow.
© BBC