Origin of Phrases - S
Smell a Rat
For centuries, it was common practice to give rat-hunting dogs free run of palaces. In the course of a quiet evening, it wasn't unusual for an animal to spring into action without an obvious cause. If no triggering effect could be found, the dog's behavior would be shrugged off as being caused by a potential rat in the area. This occurred so frequently that when an event triggers automatic suspicion in a person, that person is said to have smelled a rat.