A deterrent apparatus for small chewing mammals having open root incisor teeth that continually grow is provided. The apparatus includes an array of green light emitting diodes, a power supply, and control circuitry. The control circuitry includes power conversion circuitry coupled between the array of diodes and the power supply to regulate and control operation of the diodes. The control circuitry is configured to intermittently illuminate and deluminate the array of green light diodes. The control circuitry is configured to drive the LEDs to generate a visual output of luminous energy having reciprocity between visual intensity (I) and time of stimulus duration (T) to impart a disturbing psychophysical response via photoreceptors of a small chewing mammal that realize a constant photoreceptor effect from 0.00173 to 0.0518 seconds. A method is also provided.
