PLANET EARTH Deserts
All sorts of creatures now appear including some really unexpected ones. Toads have permeable（有渗透性的） skins and would quickly die from desiccation（siccation本身就有干燥的意思，desiccation表示使干燥） out in the daytime heat. It's only now that they can leave shelter. The same is true for scorpions（蝎子）, even though their shells are actually watertight. In fact, most small desert creatures are nocturnal（夜行）. so it's only now that you can judge just how much life there can be in the desert. But moisture, lost even at night, has to be replaced sometime somehow and that problem dominates the lives of all desert dwellers.
The Atacama（阿塔卡玛） in Chile（智利）. This is the driest desert in the world. Some parts may not see rain for fifty years and with such a record you'd expect the place to be completely barren（荒芜）. These are South America's camels, guanacos. They're very good at conserving moisture but they nonetheless need a regular supply of water. They get it partly from cactus（仙人掌） flowers but that explanation raises another question.
