The Mongol conqueror, Genghis Khan is said to have used dogs in his military campaigns that took his conquering hordes from the steppes of Mongolia, south to China and west across Russia to the frontiers of Europe.
狗的嗅覺能力超過人類二百倍。只要與一件東西接觸幾秒鐘，就能記住它的味道。幾天之後，將這個東西和其他物件混在一起，它仍能嗅得出來。