With the struggle for survival on the ground being fierce, bats took to the skies. But this is the sovereign territory of the birds, so they adopted an even better strategy and chose to go out at night when there is less competition.
地面生活競爭激烈，蝙蝠不畏萬難，「飛」上朗朗青天，但鳥族掌握了白晝的領空權，它們只好另謀策略，選擇競爭對手較少的黑夜活動。