Acoustic Kitty was a CIA project launched in the 1960s attempting to use cats in spy missions. A battery and a microphone were implanted into a cat and an antenna into its tail. Due to problems with distraction, the cat's sense of hunger had to be removed in another operation. Surgical and training expenses are thought to have amounted to over 10 million British pounds.
The first cat mission was eavesdropping on two men in a park outside the Soviet compound on Wisconsin Avenue in Washington, D.C.. The cat was released nearby, but was hit and killed by a taxi almost immediately. Shortly thereafter the project was considered a failure and decided to be a total loss. (more)