Axolotls are unique aquatic salamanders that have recently grown in popularity as pets. With their wide, staring eyes, it’s natural to wonder – can axolotls see? In this comprehensive guide, we’ll take an in-depth look at the eyesight and visual capabilities of these fascinating creatures.
If you’re short on time, here’s a quick answer: Yes, axolotls do have eyesight, but it is relatively poor compared to humans. Their vision is optimized for detecting motion and shape in murky water rather than seeing fine details.
The Anatomy of an Axolotl’s Eyes
Lack of Eyelids
One of the most unique aspects of axolotls is their lack of eyelids. Unlike most vertebrates, axolotls do not have eyelids to protect their eyes or keep them moist. Their eyes are instead constantly open and exposed to the water around them.
This gives axolotls a permanently surprised or interested look on their faces!
Without eyelids, axolotls are unable to blink or close their eyes. Their eyes are always wide open. To compensate for the lack of eyelids, axolotls have a third eyelid called a nictitating membrane that helps keep their eyes lubricated and protected.
Nictitating Membrane
The nictitating membrane is a thin, transparent inner eyelid that axolotls can draw across their eyes to help keep them moist and remove debris. It works similarly to the way humans blink, helping lubricate and protect the surface of the eye.
When axolotls are underwater, their nictitating membranes move horizontally across their eyes. Above water, the membranes move vertically. This membrane gives axolotls a way to clear their eyes and keep them functioning properly despite the lack of outer eyelids.
Limited Motion
Another unique aspect of axolotl eyes is their limited range of motion. Axolotls have eyes on the sides of their heads, like fish, allowing them to see predators and prey approaching. However, their eyes have very limited mobility within their sockets.
Axolotls are unable to look up or down without moving their entire head. Their eyes only have around 11-15 degrees of rotation. This is likely because axolotls spend most of their time looking straight ahead underwater hunting for food.
The limited motion of their eyes means axolotls rely heavily on their sense of smell to detect food and predators. Their eyesight plays a secondary role in detecting movement and shapes in their immediate vicinity.
How Well Can Axolotls See?
Poor Visual Acuity
Axolotls are not known for having great eyesight. In fact, their visual acuity is quite poor compared to many other animals. According to studies, axolotls can only distinguish clear shapes and silhouettes when objects are about 30 cm away or less (source).
Anything further than that likely appears blurry or indistinguishable to them.
There are a few reasons why axolotls have such poor eyesight. For one, they lack a focusing lens which allows other animals to see fine details. Their eyes are also quite small relative to their large heads. Additionally, axolotls spend most of their time underwater, where visibility is more limited.
Light refracts and distorts as it passes through water, making objects appear blurry.
Motion Detection
What axolotls lack in visual clarity, they make up for in motion detection. Their eyes contain a high density of rod cells, which are excellent at picking up movement (source). This allows them to spot prey easily as it swims by.
Their sideways-facing eyes give them wide peripheral vision spanning nearly 360 degrees around their head.
So while stationary objects likely appear indistinct, anything that moves catches their attention right away. This makes axolotls formidable hunters able to snap up worms, small crustaceans, insect larvae, and other passing morsels with ease.
Color Vision
Scientists are still studying the extent of color vision in axolotls. Like most amphibians, they possess rods for detecting light/dark contrasts and motion, as well as cones for discerning some degree of color (source).
However, axolotls have far fewer cones than rods, suggesting color plays a lesser role in their vision.
Nonetheless, axolotls likely utilize more color information when viewing things up close, where visual clarity improves. Research shows axolotls have trichromatic vision, meaning they can detect three color channels: blue, green and red (source).
This is an upgrade from ancestral amphibians that could only distinguish blue and green hues.
How Do Axolotls Use Their Vision?
Finding Food
Axolotls rely heavily on their sense of smell to locate food, but their eyesight also plays an important role during feeding. When an axolotl detects food such as worms, insect larvae, or small fish with its nose, its eyes help it pinpoint the exact location of the prey.
Once the prey is spotted visually, the axolotl will quickly snap it up with its jaws.
Axolotls have lidless eyes, so they are always on the lookout for food sources. Their eyes allow them to spot prey moving nearby and striking when the moment is right. Their vision is especially critical for identifying food floating in the water above them or swimming in front of them.
It allows them to accurately judge distances and angles to determine when and how to attack.
Avoiding Predators
In the wild, axolotls share habitat with potential predators like large fish, birds, and small mammals. Their eyes give them strong visual awareness to recognize threats and take evasive action. For example, if a heron is spotted flying above, the axolotl can dart under rocks or vegetation to hide.
Or if a fish gets too close, the axolotl may swim away or puff itself up to look bigger.
Their wide-set eyes also give axolotls nearly 360-degree vision around their heads. This allows them to constantly monitor all directions for any predators sneaking up on them. And if attacked, their eyes help guide precise evasive movements to dodge grasps and bites from predators.
Mating Displays
Vision plays a key role in axolotl mating behaviors. When interested in a potential mate, a male axolotl will swim around the female and perform an elaborate dance routine involving flexing motions and tail fanning.
The female watches him closely with her eyes, either signaling acceptance or rejection of his advances.
The male also uses his eyes to follow the female’s movements and align his body with hers. Visual cues help him stay close as they courtship. And when the time comes, the male relies on his eyesight to correctly position himself to fertilize the female’s eggs as they are deposited.
Signs of Vision Problems in Axolotls
Cloudy Eyes
One of the most common indications of a vision issue in axolotls is cloudy eyes. This can signify the development of cataracts, which cause the lens to become opaque and hazy. As cataracts progress, axolotls often exhibit disorientation and have difficulty perceiving objects around them.
In severe cases, cataracts can lead to complete blindness if left untreated.
Other possible causes of cloudy eye include bacterial infections, poor water quality, or injuries. Axolotls rely heavily on scent rather than eyesight for hunting and navigation, but cloudy eyes nonetheless impede crucial visual cues.
Quick diagnosis and treatment from an exotic veterinarian is imperative to resolve the underlying problem and restore clear vision.
Bumps on the Eyes
Abnormal lumps or bumps around the eyes may indicate more serious conditions such as eye tumors or abscesses. Both can obstruct vision significantly or progress to rupture the eye altogether.
Eye tumors often initially resemble a small, reddish mass behind the retina. As the tumor grows in size, it can visibly protrude from the eyeball and take on a whitish appearance. Axolotls with eye tumors may bump into tank walls, have difficulty locating food, or swim in tight circles aimlessly.
Eye abscesses also cause reddish swellings around the eyes. In addition to vision loss, abscesses lead to obvious swelling, lethargy and appetite changes. Quick veterinary attention is imperative since eye abscesses can rapidly spread infection to the brain if left untreated.
Swimming in Circles
Repetitive circular swimming, especially in just one direction, often signals a neurological or inner ear condition affecting balance and coordination. Since axolotls utilize scent over sight when navigating, swimming problems tend to manifest once there is complete blindness or severe impairment.
The onset of cataracts, eye injuries, or strokes can all instigate episodes of repetitive circular swimming if vision loss occurs.
Infections, malnutrition, or water quality issues can also impact the central nervous system and trigger circular swimming. Axolotls exhibiting this behavior are likely fully or partially blind and require prompt veterinary assessment.
With appropriate diagnosis and ongoing supportive care, most underlying medical issues leading to blindness can often be well-managed to prolong quality of life.
Caring for an Axolotl with Impaired Vision
Provide Plenty of Hiding Spots
Axolotls rely heavily on their sense of smell and feel most comfortable when they have places to hide. If your axolotl’s eyesight deteriorates, be sure to provide plenty of plants, caves, and other hiding spots around the tank.
This allows the axolotl to feel secure and avoid accidentally bumping into tank walls or decor. Popular hiding options are live or silk plants, stacked rocks creating little caves, and hollow log ornaments. Spread these out so your axolotl can easily navigate from one end of the tank to the other.
Monitor Water Quality
With impaired vision, an axolotl may have trouble finding food or notice when water conditions decline. Test the water weekly with a liquid test kit and perform partial water changes as needed to maintain excellent water quality. Target parameters are:
- Temperature: 60-68°F
- pH: 7.4-7.6
- Ammonia and nitrites: 0 ppm
- Nitrates: < 10 ppm
Poor water quality can cause additional stress for an axolotl with vision problems. Stay on top of tank maintenance to remove waste and replenish minerals axolotls need for good health.
Hand Feed When Needed
Axolotls primarily use scent to locate food. But with limited eyesight, your pet may have trouble finding food dropped into the tank. Try hand feeding daily using tweezers or tongs. Hold the food right in front of your axolotl’s face so it can smell and strike.
Target foods like earthworms, bloodworms, brine shrimp, and axolotl pellets. This ensures your salamander is getting proper nutrition. You can also use floating rings to corral food in one spot.
Caring for an axolotl with vision problems takes some adjustments but is very manageable. With a few habitat tweaks and close monitoring, an axolotl with impaired eyesight can continue to thrive and live a long, healthy life!
Conclusion
In summary, axolotls do have functional eyes and the ability to see, albeit with some limitations compared to human vision. Their eyes are adapted to detect motion and shapes in the low-light conditions of their aquatic habitat.
While axolotls won’t be reading any books soon, their eyesight allows them to hunt for food, avoid predators, and interact with potential mates. With proper care and habitat setup, even axolotls with impaired vision can continue to thrive.
