Geckos are fascinating creatures. Their eyes may be the strangest and most intriguing part of them. It’s hard to not notice how large and colorful these eyes are.
But how do geckos see? The story behind such captivating eyes dates centuries back. Read on for more about the shape, abilities, and qualities of the geckos’ eyes.
Tracing the evolution of geckos can help us understand the uniqueness of their eyes. A typical mammal’s eye consists of two photoreceptors: rods and cones. While rods receive colors in dim lights, cones are for day vision.
Geckos descend from lizards, which are day animals. In addition, those lizards are unique as they didn’t possess rods (eye structures for low-light vision). After all, they didn’t need them at all.
Yet, over many years, geckos evolved into nocturnal animals. As part of their adaptation, their eyes gained ultra-sensitive rods. Thus, their eyes acquired new enhanced abilities. In other words, geckos can see colors vividly at night.
Geckos are active during the night. They do most of their hunting and socializing in the moonlight. Thus, they need to be able to see clearly in dim light. With their enhanced color receptors, geckos’ eyes can distinguish colors even in the moonlight.
To determine these abilities, Swedish scientists have conducted an experiment. They trained helmet geckos to prefer crickets that come with a blue tag over those with a grey tag. The geckos simply learned that blue means good, and grey means bad.
The researchers placed the geckos in low-light conditions that resemble moonlight. Under such light, the human eye couldn’t tell the difference between the two colors. However, geckos’ could.
The geckos chose the blue tags even in the dim lights. These results show that geckos can distinguish colors at night. Such enhanced vision allows geckos to navigate, hunt, and escape predators.
What Do Geckos’ Eyes Look Like?
If you’ve ever noticed, geckos have interestingly large eyes. They usually have metallic colors and detailed patterns.
Geckos also have vertical pupils that are mostly split. They can expand and contract those eyes depending on the time of day.
Narrowing their eyes to little slits can protect them from sun rays and dust, but what about expanding them?
Since most geckos are more active in the dark, they do most of their hunting at night and sleep during the day. That’s why they contract their eyes during sleep for protection and expand them at night for enhanced vision.
In simpler terms, the size of the pupils determines the amount of light the eye captures. Geckos expand their eyes at night to capture every bit of light they can. The more light the eyes take in, the better they see. That’s why geckos’ eyes look huge at night.
Eyelids are another interesting feature of the geckos’ eyes. Most geckos around the world don’t possess eyelids. Out of 1500 species of geckos, around 43 have eyelids.
Interestingly, most domesticated geckos don’t have eyelids. Instead, their eyes are covered by a transparent film called spectacle. Its primary function is to protect the eyes against dust and debris.
On the other hand, some geckos have eyelids. However, they’re a bit different from those of other mammals. Although they have upper and lower eyelids, the lower one is usually stronger and larger. Even the ones with eyelids still have a spectacle.
Lacking eyelids comes at a cost. Having no eyelids to protect their eyes means:
- Geckos need to keep their eyes moist to prevent them from drying out.
- Eyelid geckos have to find an alternative to closing their eyes while sleeping. That’s why they narrow their eyes significantly.
- Geckos have to clean their eyes regularly to prevent infections.
Eublepharidae is the only gecko family that has moveable eyelids. Now, why do these geckos have eyelids?
There’s no clear answer to this question. However, there’s a theory that these geckos need eyelids to adapt to their habitat.
Although they’re spread across the world, they mostly live in sandy areas, where they need eyelids for protection.
If you keep a gecko as a pet, you must have seen it licking its eyes with its tongue. Why does this happen?
Geckos have flexible tongues that are usually sticky and moist. That’s why they use them to clean their eyes and keep them moist.
In addition, most geckos prefer warm, arid habitats. Licking their eyes can raise their temperature and keep them warm when the cold strikes.
The eye-licking habit also gives them better vision and protects them against several eye problems.
Think about it. How would geckos blink if they have no eyelids? The answer to this question depends on the species.
Only geckos with moveable eyelids can blink. However, the majority of gecko species don’t have eyelids to allow them to blink.
Yes, geckos have super strong eyesight. It can be up to 350 times stronger than that of humans.
Geckos have three types of cone cells. This variety allows them to see all colors, even those within the ultraviolet range of the light spectrum.
Another fantastic feature is the geckos’ multifocal abilities. This ability is inherited directly from their ancestors, the lizards.
With multi-focal vision, geckos can see several objects at different distances at the same time. Thanks to their large vertical eyes, geckos have outstanding eyesight.
Geckos can move their eyes separately, allowing them to see in all directions. Some species of geckos see up to 360 degrees around them.
Using their profound eyesight, geckos can see objects at all ranges. They see both close-up and distant objects.
If you have a pet gecko with eyelids, you might have noticed that it closes only one eye sometimes.
The most basic explanation is that the gecko is sleeping, especially if this happens during the day. Some geckos keep one eye open as they sleep to avoid predators.
Closing one eye can also be due to several other reasons, including:
- Eye injury: it can be due to a bruise or a scratch in or around the eye.
- Shedding problem: geckos shed their skin regularly. Perhaps, a piece of shed skin is stuck in the eye.
- Dry eye: geckos can also suffer from dry eyes. This can be a result of low humidity or low moisture levels.
- Debris: this can range from dust particles to large materials that can get stuck in the eyes of your gecko.
- Parasites: different types of parasites can get into your gecko’s eyes. If this happens, look closely to see if anything is swimming around in the eyeballs.
- Vitamin Deficiency: it might mean that your gecko needs more vitamin A.
- Infections: geckos can develop fungal, bacterial, or viral infections.
- Subcutaneous abscess: that’s a soft lump under the skin around the eye.
- Wrong light conditions: if you keep a gecko in your tank, you should provide the right amount of light. Remember that their eyes are super sensitive, so additional light may cause them to shut an eye.
How do geckos see? They see 350 times better than us. Thanks to their sensitive color receptors, geckos’ eyes can distinguish colors, even at night.
Geckos have interesting eyes with unique shapes, patterns, and colors. Most gecko species don’t have eyelids. Instead, they use their tongues to keep their eyes clean and moist.
Geckos are incredible animals that would certainly impress you with their eyes’ abilities.
I have a bachelor’s degree in Film/Video/Media Studies, as well as an associates degree in Communications. I began producing videos and musical recordings nearly 15 years ago. I am a guitarist and bassist in Southwest MI and have been in a few different bands since 2009, and in 2012 I began building custom guitars and basses in my home workshop as well. When I’m home, I love spending time with my three pets (a dog, cat, and snake) and gardening in my backyard. I also like photographing wild birds, especially birds of prey.