Reduced exposure to microwave radiation by rats: frequency specific effects.
D'Andrea JA, DeWitt JR, Portuguez LM, Gandhi OP. · 1988
Rats given the choice consistently moved away from microwave radiation when it was turned on. They avoided certain frequencies more strongly than others, demonstrating that animals can sense and actively avoid microwave exposure at levels as low as 2.1-2.8 watts per kilogram.