Snakes have been around for centuries, yet much about them remains unknown. Snakes have a unique way of sensing the world around them, and you might have heard different stories about a snake’s eyesight. Some likely left you wondering if snakes even have eyes.
Snakes have eyes but rely on heat and vibrations to sense their surroundings. They collect air molecules with their tongue and interpret them to detect and locate prey. They can also detect vibrations in the earth and air and sense infrared radiation emitted by body heat.
In this article, I explore the most commonly asked questions about snake eyesight. You’ll learn how this fascinating reptile can see and why scientists believe they have supersight.
Are Snakes Blind?
There are hundreds of blind snake species, but even they have eyes. During their embryonic development, the eyes of blind snakes reduce in size. This leaves them with incredibly poor eyesight when they hatch, making them blind.
A blind snake’s eyes don’t have any purpose. The best explanation for this is that both blind snakes and those that can see have the same ancestors.
Due to evolution, the eyes of blind snakes change during their development. If logical predictions are correct, blind snakes may be born without eyes in the future. Over time, they will keep evolving to a point where the development of eyes is unnecessary.
Blind snakes don’t need to see. Most of these species live underground and only resurface after heavy rainfall. They use their excellent sense of smell to detect the trail of their prey. This helps them “see” where to go.
You won’t be able to tell a snake is blind by quickly passing by it. Smaller eyes could be a giveaway, but this isn’t always accurate. Clouded eyes are also a sign of other issues.
Your snake can go blind for various reasons. If you suspect it is, seeking help from a specialized vet is your best bet.
How Snake Vision Works?
Snakes have eyes, but they don’t see as we do.
Human eyes have three cones, each reacting to a different light wavelength: red, green, and blue. This gives us trichromatic vision. Meanwhile, snake eyes have only two cones, which means they have dichromatic vision. You can imagine it as seeing the world in black and white.
However, there is a lot of variety among the eyes of different snake species.
The eyes of nocturnal snakes are very sensitive to UV light, allowing them to see in low-light conditions. Meanwhile, UV light can impair vision during the day, which is why the eyes of diurnal snakes have a coating that filters out UV light. This is what gives a yellow appearance to the eyes of some snakes.
Arboreal snakes have larger eyes and better vision than terrestrial snakes. They have developed horizontal pupils that allow them to detect movement extremely well and jump from one branch to another with great precision.
Aquatic snakes have better color vision compared to snakes not living underwater. Moreover, the vision of aquatic snakes has diversified at a faster rate than that of ground-dwelling snakes. Researchers have determined that these species have been refining their vision since entering the waters more than 15 million years ago.
Ground-dwelling and burrowing snakes can do well with little to no vision. And as I already mentioned, some snakes that live underground have foregone their vision entirely.
What makes snake eyes even more remarkable is how they continue to evolve. Snake eyes constantly adapt to their surroundings, and the diversity in their eyesight is remarkably high.
How Do Snakes See Humans?
Snakes see humans as shapes with no details during the day. During the night, they can sense humans thanks to their infrared detection and see them in more detail.
As I explained above, snakes don’t see the world as we do. We can perceive myriad colors, but their color perception is very limited. Luckily, snakes have other ways to detect humans, especially if it’s someone they know.
Although snake vision varies from species to species, most snakes will see us a bit differently depending on how much light they have to work with:
- Daytime eyesight: During the day, snakes see two colors. Most species have trouble seeing when it’s bright outside, so their sensitive eyes filter most of it out. Snakes that can see during the day mostly see humans as shapes with no details.
- Nighttime eyesight: Snakes detect infrared radiation during the night. They have pit organs on their faces that convert heat into electrical signals that help them “see” humans and prey. At night, they can easily locate a nearby human and might be able to perceive more detail.
How Snakes Use Their Eyes To Hunt
Snakes that hunt in daylight have lenses before their eyes that block UV light, allowing them to see their target in more detail. At night, a snake’s eyes allow more UV light in to help them see better in the dark.
Nonetheless, most snakes have poor eyesight. They identify the silhouettes of animals and objects well enough, but they don’t perceive color and can’t see their prey from a distance. This might be a little surprising when you consider how competent snakes are as hunters, but the truth is that they rely on their other senses to stalk and kill.
Snakes can detect vibrations to help them hunt. Once their body picks these vibrations up, they know where to focus their eyes. Moving animals make vibrations, and snakes interpret these in a similar way that we interpret sound waves.
Snakes use their body surface to detect the tiny “ripples” made by an animal moving in the sand with great precision. They can also sense airborne vibrations with their skulls, but this mechanism isn’t entirely understood.
Snakes that hunt at night use infrared “vision,” but this isn’t done by their eyes. Certain snakes, such as vipers and pythons, have little holes in their faces called pit organs. These pits detect the infrared radiation emitted by the body heat of their prey.
Snakes’ infrared vision has a range of about one meter, so it doesn’t let them locate their prey at a distance. However, it does allow them to deliver accurate strikes even when there’s little to no light.
Snakes Have Poor Vision
It should be clear by now that snakes don’t have the best vision in the animal kingdom. They still use their eyes in conjunction with their other senses to find prey, but it’s not their main tool for navigating the wild.
Humans use their eyes to see where to go or what to do, but snake vision becomes more useful once they have that information. They first detect vibrations, heat, or chemicals and then use their vision to aid them in looking for prey. Imagine if our eyesight and other senses were so in sync!
Can Snakes Close Their Eyes?
Snakes can’t close their eyes because they don’t have eyelids. Instead, they have a transparent membrane covering their eyes. These are called brilles or spectacles and protect a snake’s eye from drying out. The spectacles are attached to their skin and can’t move.
A sleeping snake has its eyes wide open. The best way to guess if a snake is sleeping is by seeing how still it is. Sleeping snakes typically stay in one position for hours. They also won’t move if there’s activity around them.
Pet snakes adapt to sleeping for longer periods. If you encounter a still stake in the wild, moving slowly and away from it is best. Snakes can sleep up to 20 hours daily, but they’re always dimly aware of their surroundings. Snakes will awake when they detect movement, and they feel especially threatened while asleep.
Do Snakes See With Their Tongue?
Snakes don’t see with their tongues, but they use this organ to better understand which direction they should go.
A snake’s tongue collects particles from its environment. These are transferred to their Jacobson’s organ, where it’s interpreted.
Jacobson’s organ is located on the roof of a snake’s mouth. Once its tongue collects chemicals from the air, ground, or water around it, a rapid exchange takes place. The receptors in the Jacobson’s organ send a message to the snake’s brain once it receives the chemical compounds.
A snake’s tongue and Jacobson’s organ help it accurately locate its prey. In fact, they rely more on this sense than on their eyes when hunting.
Final Thoughts
Snakes rely on all of their senses to navigate the world and find prey.
They are able to taste the chemicals in the air with their Jacobson’s organ, which allows them to locate animals. They can sense infrared radiation, which means they can detect the body heat of prey within a short range. Snakes can also sense their environment through vibrations.
It’s easy to see why snakes fascinate the scientific world. We may never understand how it feels to see the world as a snake, but what we can determine provides valuable insight.