Fertebrate Observation

The rods and the cones are both types of photoreceptors that are found in vertebrate eyes. The rods, which are far more numerous than cones, help seeing in the dark (low-light) settings, and they are not responsible for color vision. On the other hand, cones help see color. These are two main differences, but they also differ in shape. While cones are short, rods are long.
I would expect nocturnal animals to have mostly rods, since those are needed for better vision in low-light setting such as during night. On the other hand, I would expect animals that spend more time active during the daylight to have mostly cones, since those are needed in brighter settings such as during the day, and they are needed to see
colors.