In The 1960s, The CIA Turned Cats Into Bionic Spies
io9 has an excerpt from Emily Anthes's new book, Frankenstein's Cat: Cuddling Up to Biotech's Brave New Beasts, in which she details the experiments:
In the 1960s, the Central Intelligence Agency recruited an unusual field agent: a cat. In an hour-long procedure, a veterinary surgeon transformed the furry feline into an elite spy, implanting a microphone in her ear canal and a small radio transmitter at the base of her skull, and weaving a thin wire antenna into her long gray-and-white fur. This was Operation Acoustic Kitty, a top-secret plan to turn a cat into a living, walking surveillance machine. The leaders of the project hoped that by training the feline to go sit near foreign officials, they could eavesdrop on private conversations.
Turns out the cats weren't interested in participating. During their first outing their suicidal subject wandered in front of a taxi.