Here’s an article about bunny vision:
http://www.bio.miami.edu/hare/vision.html
“What about color vision? In general, vertebrates have two different types of photoreceptor cells in their retinas: rods and cones. Cones confer high resolution, and, if more than one cone type is present, they also confer the ability to perceive various wavelengths of light as distinct colors. For example, we humans have three different categories of cone–their maximum sensitivities in the red, blue and green regions of the spectrum. The differing sensitivities of each cone type enable us to perceive different (visible) wavelengths of light as the colors of the rainbow.
Behavioral studies published in the early 1970’s indicate that rabbits do have a limited ability to discriminate between some wavelengths of light, perceiving them as different colors. Evidently, they can discriminate between the wavelengths we call “green” and “blue.” Although rabbits may not perceive green and blue the way we do, they *can* tell them apart. This means they have limited color vision, probably conferred by two different categories of cone cells (blue and green).”