When it comes to the wild, animals and insects cover an exhaustive field of biological diversity. The majority of spiders have eight eyes and poor vision, while flies have hundreds of tiny lenses and near-360-degree vision. Eagles can spot a mouse from over one mile high or 1.6 km, while a sloth has trouble seeing any animal that isn’t moving. Considering this vast diversity, whether or not animals see in color is a question that must be taken species by species.
In humans, rods and cones in the eye’s retina detect light and color, respectively. Rods allow us to see shapes in dim light and make our way down the hall in the middle of the night. Cones, which detect color, require more light to activate. For this reason you might notice that you don’t see color in the dark; instead, everything appears in shades of gray. Flip on a light, and the retina’s cones activate, relaying color information to the brain.