The title of this article is a bit misleading: no animals can actually see in complete darkness. Animals with so-called “night vision” take a small amount of light and maximize it through evolutionary and physical advantages to see in dark conditions. While we may look outside and see nothing but pitch black, the animals on this list have learned how to travel, hunt, and live with just a little light. Let’s dive into the list of 5 animals that can see in the dark!
1. The Walleye
The Walleye is a fish that has excellent night vision, despite living in incredibly murky, low-light conditions. The Walleye (and other fish that live in dark environments) actually has a greater number of rod cells than cone cells to make the most of whatever light penetrates its home. It is estimated that, in ideal night conditions, a Walleye could see prey up to 50 feet away. Interestingly, although the Walleye can see in the dark, their vision is not detailed.
Both rod cells and cone cells are in the retina. Rod cells are suited to low light and provide us with black and white vision (and shades of gray, technically). Conversely, cone cells provide us with color vision and are more suited to bright light. The concentration of rod and cone cells varies across animals, but many of the most common nocturnal animals have visual adaptations such as this one.
2. Owls
Owls have incredible night vision. It’s estimated that they can see anywhere from 10 to 100 times better than humans in the dark and low-light conditions. There are several features owls have for great eyesight, but the primary cause is their higher concentration of rods. Owls also have concave facial discs which actually helps funnel light toward their eyes.
Like some of the other animals on this list, owls need some sort of light to see in the dark (even if it’s a tiny amount). But owls can maximize their use of light for great night vision by independently dilating their eyes. Unlike humans and other animals, owls have complete control over the degree of dilation for each eye. This means that they can make their eyes dilate more in extremely low-light conditions and scale back the dilation on clear or bright nights. This dilation is made even more effective by how large an owl’s eyes are: approx. 3% of their total body weight and size.
3. Aardvarks
The aardvark is a study in visual contradictions. Aardvarks are colorblind but still have great night vision; aardvarks have poor visual acuity but are still far-sighted. In fact, aardvarks are one of the only animals that exclusively have rods in their eyes and no cones at all. (Note: despite common mix-ups, aardvarks are different from anteaters.)
Aardvarks also use their eyesight to remain agile and avoid predators. Though aardvarks often move slowly, they can run up to 30 miles per hour when necessary and can even jump up to four feet high. This higher level of activity is seen most often when aardvarks first leave their burrow in the evenings. Aardvarks will charge out of the burrow and jump around to assess whether predators are nearby.
4. Raccoons
Raccoons are known for being night bandits and their stealth is significantly aided by their excellent night vision. (As a reminder, their nocturnal habits are just one reason why raccoons don’t make good pets.) Key to their nighttime success is a tapetum lucidum, which is a crystalized, reflective layer behind the retina that effectively doubles the amount of light a raccoon can see.
The tapetum lucidum acts as a mirror: when light passes through the retina, the tapetum lucidum bounces the light right back to the retina’s photoreceptors. In other animals, the light is absorbed by the photoreceptors (e.g., the rods and cones). Pro tip: If you’re unsure about whether an animal has this reflective layer, check their eyes in the dark. Shining eyes means that they have a tapetum lucidum. You can also use a flashlight or camera to get this effect.
5. The Aye-Aye
The aye-aye is the largest nocturnal primate in the world, so it’s only natural that it would make an appearance on this list. The aye-aye’s powerful eyesight is matched only by its extremely sensitive hearing. And in an interesting twist, the aye-aye relies more on its hearing for tracking prey. Their great eyesight seems to be primarily used for navigating the dozens of miles that their territories stretch across.
But aye-ayes aren’t just unique for their saucer-like eyes and ears (and weird, twig-like middle fingers): despite being a nocturnal primate, their color vision has not degraded over time. Prior to studying aye-ayes, the prevailing evolutional theory for nocturnal primates was that color vision was redundant, so the genes controlling this have faded over time (“use it or lose it,” if you will). Researchers now believe that the aye-aye’s color vision may be completely intact and are in the process of running further tests.
