Reportedly, highly intelligent and adaptable ravens were trained for military intelligence operations, especially during the Cold War.

According to some experts, ravens are among the most intelligent birds with large brains functioning at a level similar to a small monkey, and with many human-like characteristics.Reportedly, these adaptable creatures were trained for military intelligence operations, especially during the Cold War.

U.S. Government agencies have tried training everything from dolphins and bugs to cats and pigeons. But 76-year-old Bob Bailey – who trained animals for the military during the 1960s and 1970s - calls out ravens first as among those successfully used in real-life scenarios.

Experts John Marzluff and Tony Angell say ravens along with other corvids like crows "assume characteristics that were once ascribed only to humans, including self-recognition, insight, revenge, tool use, mental time travel, deceit, murder, language, play, calculated risk taking, social learning and traditions."

Largely solitary but common among people, ravens can go unnoticed even when vocal. They can recognize patterns and certain types of objects; carry extremely heavy objects in their beaks or open drawers; use sword-like weapons and in the case of a New Caledonian crow - even bend wires into hooks.

Ravens were allegedly trained to place or retrieve a camouflaged audio device when directed to a specific window sill but it is not clear they were ever used in reality. A more impressive but unverified approach included the raven pressing a camera in its beak on the window with enough force to snap a picture.

Today, using animals for spy purposes is largely obsolete due to technology so we can assume ravens aren’t spying on us anymore. Or are they?