Start with the animal the words actually name: a small creature that gets by in a place where almost nothing does. It lives in a hole, comes out when the ground cools, knows exactly where everything is, and needs very little. Every other use of desert rat takes that small tough survivor and hangs it on a person who has lived in the desert long enough to be like one.
One branch
被這樣叫的人
把那隻小生物的形象——在沙漠裡活得下來、熟門熟路——拿來當人的綽號。這是比喻上的借用，不是說這些人的名字從動物「演變」而來。
noun · C1
A nickname for a soldier who served in the desert of North Africa in the Second World War, in the British 7th Armoured Division; the sources also count Australian soldiers who served with them.
沙漠之鼠（二戰北非英軍）