In the 1960s, two Siamese cats were asleep in the study of Henri Helb, the Dutch ambassador to Russia. Suddenly, they bounced up, arched their backs and started scratching the wall.
This was because the cats had heard the sound of the mics being turned on; a sound imperceptible to humans. Thanks to the cats, they found 30 other microphones around the embassy.
Instead of complaining to the Russians, they used the microphones to their advantage. For example, they once grumbled about how long it had taken to repair an embassy sewer. It was fixed the next morning.