美CIA基本上就是把麦克风，发射器植入猫耳，头部和皮肤下，再送入莫斯科和苏联大使馆进行监听。 6park.com
Acoustic Kitty
 was a CIA project launched by the Central Intelligence Agency Directorate of Science & Technology, which in the 1960s intended to use cats to spy on the Kremlin and Soviet
 embassies. In an hour-long procedure a veterinary surgeon implanted a 
microphone in the cat's ear canal, a small radio transmitter at the base
 of its skull and a thin wire into its fur.[1]
 This would allow the cat to innocuously record and transmit sound from 
its surroundings. Due to problems with distraction, the cat's sense of 
hunger had to be addressed in another operation.[2] Victor Marchetti, a former CIA officer, said Project Acoustic Kitty cost about $20 million.[3]
 6park.com
https://en.wikipedia.org/wiki/Acoustic_Kitty