Rabbits Can’t See Red

Rabbits only have photoreceptors for seeing blue and green light, yet they are not entirely color-blind. Red, green, and blue are the three categories of color receptors that humans have in their eyes, but since rabbits lack red light receptors, these wavelengths are likely to appear to the rabbit as grayscale or as different shades of green and blue.

Rods and cones are used by the retinas of animal eyes to detect color and light. Animals' ability to discern fine details and various color wavelengths means that their world is not entirely black and white. Rabbits lack the category of cones that can detect red wavelengths of light, and have significantly fewer cones than humans.

It is thought that humans developed strong color perception because it enables us to distinguish between the hues of various fruits and berries while foraging. Although rabbits can eat berries, historically they have mostly consumed grasses, leaves, and roots. Red vision wouldn't have had much of an impact on their survival, even though color vision on the green and blue spectrums had some advantages.