Have you ever really given thought to what animals and insects can really see through their lenses? Probably not too much. The reason for that is that we are generally quite aware of our slightly superior visual acuity, which is not far from the truth, however, there is another side to it. Animals and insects can see things that the naked human eye couldn’t dream of seeing. In short, there is, in fact, an entire world right in front of us that we will never see.
Let’s take a quick look at how colour vision works. As mentioned in a previous article “What is Colour Vision”, every surface of an object emits a certain number of wavelengths. These wavelengths of reflected light determine what colour you see. The light waves reflect off the object and hit the light-sensitive retina at the back of your eye. At the back of the eye, the light wave reaches what are known as cones. These cones are a type of photoreceptor. Not all the cones are receptive to the same colour. However, there are three main colour receptors, red, blue and green.
How we see colour works the same for all living things, however, the cones are receptive to different colours for animals and insects. Now that we understand how it works let’s have a closer look at some examples of animal visual acuity.
Bumblebees are receptive to yellows, blues, and ultraviolet. Meaning they can see the mixes of yellow and blue. These are not colours that the human eye is susceptible to at all, meaning they see wavelengths we cannot. The UV information of the flower nectar helps guide them to the nectar of the flowers as flowers have patterns in the UV range that we can’t see.
Contrary to popular belief, dogs can see in colour. However, they possess blue, and yellow cones but not red. Although their vision is much blurrier than ours, they can pick up motion from a further distance much better than we can. Dogs are also able to see better in dimmer lighting.
Birds have at least four types of cones: UV, blue, red, and yellow. There is talk that they have even more cones. It’s almost impossible to imagine what birds can see through their lenses.
Moral of the story, don’t judge an animal by its eyesight. They may not have the visual acuity you, and I possess, however, they see the world through different eyes.