Dolphins weren't the half of it. In the 1960s, the United States military began training dolphins as undersea agents, using them to seek out mines and covert swimmers. It's a well-known piece of military history, and fiction has embellished that in the decades since. In William Gibson's Johnny Mnemonic, the cybernetically-enhanced dolphin Jones was a skilled Navy-trained hacker. In the video game Command & Conquer: Red Alert, dolphins equipped with sonar weaponry fought for the Allied Navy. But the reality of military animal training is just as wild as the fiction; outside of dolphins, it turns out that all sorts of animals, from ravens to house cats, were specially trained as spies during the Cold War.
While dolphins were trained by the Navy, it was actually the CIA that trained animals to be covert Cold War spies. And the CIA had help from an amazing source, as detailed in Smithsonian Mag's feature on the history of animal spies: the animal trainers behind a zoo in Arkansas that was open from 1955 to 1990. The IQ Zoo showed animals performing an amazing variety of tricks, from birds riding bicycles to pigs playing (or at least attempting to play) pianos.
The I.Q. Zoo was founded by Keller and Marian Breland, who were former graduate students of B.F. Skinner. Skinner, whose name you may recognize from the idea of the Skinner box, was a pioneer in psychology and conditioning. The Brelands learned animal conditioning from Skinner and applied that knowledge to a variety of practices--training animals for TV commercials and zoos and theme parks--before eventually opening the I.Q. Zoo. Soon they were invited to help the Navy in its research into training dolphins. In the end, one of the Navy's experts, Bob Bailey, joined up with the Brelands, and soon the CIA came knocking.
The CIA wanted help training animals for espionage work. Birds, for example.
"When Bailey describes the Western raven, he sounds as if he’s talking about Jason Bourne."
Smithsonian Mag writes: "When Bailey describes the Western raven, he sounds as if he’s talking about Jason Bourne. 'It operates alone, and it does very well alone,' he says. Western ravens are adept at pattern recognition. 'They could learn to respond to classes of objects,' he says. 'If you’ve got a big desk and a little desk, you could train it to always go to the small one.' They can also carry quite a load. 'These things could pick up weights, heavy packages, even file folders,' he says. 'It was incredible to watch these ravens carry a load in their beaks that would have defeated an ordinary bird.' They also, he says, could be trained to open file drawers."
Cats, too, were trained by Bailey and the CIA, though classified documents make it hard to know how successful they ever were. "In what has come to be called the 'acoustic kitty' project, the CIA’s Directorate of Science and Technology proposed using a cat as a listening device," writes Smithsonian Mag. "Working with Robin Michelson, a California otolaryngologist and one of the inventors of the human cochlear implant, the team turned the cat into a transmitter—with, says Bailey, a wire running from the cat’s inner ear to a battery and instrument cluster implanted in its rib cage. The cat’s movements could be directed—left, right, straight ahead—with ultrasonic sound."
Ravens were used to drop listening devices in specific locations. Pigeons were trained to fly ahead of troops and land if they spotted enemy soldiers, acting as a warning mechanism. If they didn't spot troops, though, they just kept flying...and never came back.
Bailey told Smithsonian Mag that the CIA's animal spies did indeed see some real world use, but much of the research was just that--research. Still, it's a fascinating era of espionage that made up for limited technology with ingenious psychology. The rest of Smithsonian Mag's story goes into detail on how the animals were trained both inside and outside the intelligence community. Give it a read, if only to figure out how the chickens at I.Q. Zoo always won at tic-tac-toe, and how Bailey even used psychological conditioning on bugs to test how far training could go.