Our eyes are easily the most complex sensory organs we have.
Our ability to see the world around us in clear, precise images is frankly incredible. But since we are a diurnal (awake during the daytime) species, our night vision is nowhere near as powerful as that of many animals.
Human Vision Tag-Team: Rods and Cones
Two of the most important types of cells involved in making vision possible are rods and cones. Cones, in human eyes, come in three varieties: red, green, and blue light sensitive. These cells are what allow us to see sharp, detailed images full of color. The reason some people are colorblind is that they’re missing one of the types of cones, which limits the range of colors they can perceive.
The biggest weakness of cones is that they only work with a lot of light. Any darker than about the brightness of the night of a half moon and the cones can’t function. That’s where the rods come in. Rods can function in much dimmer light, but they can’t detect the different wavelengths (or colors), and the overall picture they generate is far less sharp or detailed.
You may have noticed that you can see objects better in the dark when you aren’t looking directly at them. That’s because we have more rods around the edges of our retinas, while the center (the macula) is densely packed with cones.
The Animals With The Best Night Vision
Which animals would you think have the best night vision in the animal kingdom? Owls? Cats? While both do have exceptionally good night vision, the answer is actually frogs. Based on current research, frogs (and toads) are the only animals that can see in color in almost total darkness. This is because their rods come in two different sensitivities, like the way our cones come in three.