In fact, most small desert creatures are nocturnal. 事实上 大多数小型沙漠动物 都是夜行动物

122. It's only now that they can leave shelter.
     所以只有到了晚上它们才能离开庇护所
123. The same is true for scorpions,
     蝎子也是同样的情况
124. even though their shells are actually watertight.
     尽管它们的外壳其实并不透水
125. In fact, most small desert creatures are nocturnal.
     事实上 大多数小型沙漠动物 都是夜行动物
126. so it's only now that you can judge just how much life there can be in the desert.
     所以只有此时你才能判断 沙漠中究竟有多少生物
127. But moisture, lost even at night, has to be replaced sometime somehow
     可是水分在晚上也会损耗 必须在什么时候想办法补充
128. and that problem dominates the lives of all desert dwellers.
     这一问题支配着所有沙漠动物的生活

来自《行星地球 第一季 第五集 Planet Earth S01E05 沙漠》第 125 行