大象传媒

David Attenborough watches free-tailed bats in a cave in Texas. At over a month old, the babies get ready to accompany the adult females when they return to the males in Mexico. But they're far from expert fliers and for several days they've been setting out on short practice flights within the cave. Now, some accompany the females out into the open and it's soon clear that not all bats will make it. One has crashed in a bush just outside the cave and David sets it off on its journey again. One in a hundred babies dies in the cave, where it's relatively safe. Out in the open there are many dangers and of the million bats born just five weeks earlier in the cave, around three quarters will perish on the journey. The trials of their lives are just beginning.