Excerpted from "What Do Dogs Know?":

Whether dogs know it or not, they often rely more upon instinct than upon knowledge or education. During World War II, the Nazis stationed along the Maginot Line used dogs as messengers. The French soidiers tied to shoot these dogs, but they were difficult to hit because they moved so quickly and silently.

One French dog handler then tried an experiment, releasing a small female French messenger dog who had just gone into heat. As she had been taught, the French dog returned to her post later that evening.Trailing behind her were nearly a doren normally obedient German Army dogs who had discovered something much more powerful than their milItary training.