For centuries, bats have been shrouded in folklore, mystery and myths. One of the most enduring misconceptions is the idea that bats are blind. This myth is so pervasive that it has seeped into language and given rise to phrases like ‘blind as a bat’. This misunderstood fact has perpetuated myths about bats for centuries leading to a fascinating intersection of biological, cultural and scientific misconceptions.

When someone utters the phrase ‘blind as a bat’ they likely intend to describe a state of disorientation or poor vision. However, the phrase is not only misleading but also entirely inaccurate. However, contrary to that popular belief, bats are not blind. In fact, depending on the species, bats can see with their eyes and quite well! Their vision plays a crucial role in their survival.

This stamp from Moldova in 1999 has bat images due to folklore

In this blog post, we will delve into the fascinating world of bat vision and go exploring how they use their eyes alongside echolocation to navigate in their environment. We will read about how bats use their vision, why the myth of blindness persists and the extraordinary adaptations that make bats one of the most remarkable creatures on Earth. Let us even have some amusing anecdotes and captivating stories to keep things lively.

The myth’s origins

The misconception that bats are blind likely stems from their nocturnal habits and reliance on echolocation. Observers noted their ability to navigate in complete darkness and assumed their eyes were ineffective or vestigial. This assumption was compounded by the small size of bat eyes in many species leading people to believe their vision was negligible. Additionally, bats' erratic flight patterns contributed to the belief that they were flying blindly. Their flight patterns can seem unpredictable to the human eye. These factors, coupled with cultural folklore and language idioms, buried the myth into public consciousness.

Vampire bite is taken from vampire bats biting cattle for drawing nutrition from their blood

Because they are rarely seen during the day and often use high-frequency sounds to find their way in the dark, it’s easy to assume their vision is redundant. However, this could not be further from the truth. Some stories in folklore painted bats as mysterious and even sinister creatures. For instance, in certain European legends, bats were associated with witches and considered omens of darkness. These tales, while entertaining, didn’t help bats’ PR when it came to their visual capabilities. Bats have become a misunderstood creature due to all these factors at play.

**Dispelling the "blind as a bat" myth**

The phrase ‘blind as a bat’ couldn’t be more misleading! Bats have evolved over millions of years to become masters of nocturnal navigation and their vision plays an integral role in their procreation and survival. It’s important to appreciate the sophisticated adaptations that allow these creatures to thrive in their respective habitats. Here are some quick facts to highlight their visual capabilities…

Fruit bats have colour vision similar to humans which helps them locate nectar-rich flowers and ripe fruits.

Microbats can detect ultraviolet light which helps them in recognising reflective surfaces and subtle changes in their environment.

Bats are not dependent on light alone and they seamlessly switch between echolocation and vision depending on convenience and environmental conditions.

Debunking other myths about bats

The myth of blindness is just one of many misconceptions about bats. Here are a few others that deserve clarification…

Bats can get tangled in hair – Bats are highly agile flyers and have excellent spatial awareness. They are unlikely to accidentally collide with humans let alone get tangled in your hair. The idea of a bat intentionally targeting someone’s coiffure is the stuff of slapstick comedy and not actual biology.

All bats drink blood – Only three species of bats are vampire bats and they feed primarily on the blood of animals like cattle or livestock. The vast majority of bats are frugivorous, insectivorous or nectarivorous. Vampire bats (while infamous) are just a tiny fraction of the bat family.

Upclose face of a vampire bat

Bats are dangerous or dirty – While bats can carry diseases like rabies, they play a vital role in ecosystems by pollinating plants, controlling insect populations and dispersing seeds. Proper education and precautions can help mitigate such risks without demonising these creatures.

Why do bats need good vision anyway?

Foraging – Certain bats, especially fruit bats, rely on their vision to locate their food. Their ability to discern colours and shapes helps them identify blooming flowers or ripe fruits which may not be easily detectable through echolocation alone. Imagine a bat named Barry on a mission to find a mango tree. With his sharp eyes scanning for the golden glow of ripe fruit and his echolocation guiding him through dense branches, Barry is an unstoppable until he strips the tree of all it’s mangoes.

Navigation – Bats often travel long distances between feeding grounds and roosting sites. Visual cues such as familiar landscape features or the position of the moon, play a crucial role in navigation especially for species that migrate.

Social interaction – Vision is also essential for recognising other bats within a colony. In species where social behaviour is complex such as in flying foxes, visual recognition helps maintain group cohesion and hierarchical structures. Picture a bat reunion where they’re not just using sound but giving each other approving glances.

Bats have formed a social colony inside Puthia Rajburi which is a historial palace in Bangladesh

Facts about bat vision – The anatomy

The eyes of all bats are actually functional. Bats are like all mammals. All bats, regardless of species, have eyes that they use for vision. While their eyes may not be as large or prominent as those of some other mammals, they are by no means ineffective. They have eyes that are adapted to their specific needs. In fact, many bats have eyes adapted to their specific ecological needs that allows them to see well in their natural environments. Their eyes may vary in size depending on the species. Bats are an incredibly diverse group with over 1,400 species divided into two main suborders…

Megabats (fruit bats or flying foxes) – Also known as fruit bats or flying foxes, megabats rely primarily on their vision rather than echolocation. These bats tend to have larger eyes that are well-suited for daylight and low-light conditions. They have large forward-facing eyes with excellent colour vision and depth perception are their vision is similar to primates. This is essential for locating fruit and navigating through dense foliage during the day or twilight hours. They rely on their vision to find fruits and nectar.

A grey-headed flying fox is a good example of megabats

Microbats (insectivorous bats) – These smaller bats typically have smaller eyes but are still capable of seeing. Their vision is adapted to low-light environments which helps them detect movement and objects even under the faintest starlight. They primarily rely on echolocation to hunt for insects in the dark. While their eyes are typically less developed than those of megabats, they are still functional. Some microbats have evolved a degree of colour vision and sensitivity to dim light.

Small fruit bats are examples of microbats

Retinal structure – Most bats are crepuscular or nocturnal, meaning they are active during twilight or nighttime. The retina in a bat's eye contains a high density of rod cells which are highly sensitive to dim light. Rod cells are photoreceptor cells in the retina that detect light intensity and motion. This adaptation allows bats to see in low-light conditions and makes them excellent at navigating during twilight or moonlit nights. However, the amount of cone cells which are responsible for colour vision, varies among species. Some bats can see in colour while others rely more heavily on shades of grey…albeit in shades of grey rather than vibrant colours.

Ultraviolet sensitivity – Some bats can see ultraviolet (UV) light which enhances their ability to detect flowers, fruits or other food sources that emit UV patterns. This adaptation is particularly useful for species that feed on nectar or ripe fruit. UV vision is like having a hidden treasure map glowing before their eyes.

Here’s an amusing titbit – A bat’s eyes are so well-suited to it’s environment that some species might actually scoff at us humans for our reliance on contact lenses and glasses. Imagine a bat holding a tiny optometrist’s chart “Can you see the E? Good, now spot that moth at 50 metres!” Imagine you’re a bat that’s swooping through a moonlit forest. While humans would be tripping over tree roots, you’d effortlessly glide between branches spotting a ripe fruit hanging delicately from a tree – a midnight snack served by Mother Nature herself, huh?

How good is the bat vision?

Bats’ vision is not only functional but exceptionally sharp in some cases. Research has shown that certain species of bats (particularly fruit bats) have visual acuity comparable to humans in daylight. Some bats are also thought to have UV-sensitive vision which helps them detect flowers and fruits that reflect ultraviolet light outwards.

For insectivorous bats that hunt at night, their eyesight is not as sharp as that of daytime animals but it is also perfectly built for detecting shadows, shapes and movement in dim light. This visual ability complements their echolocation by providing a dual system for navigating their environment.

Echolocation + vision – A powerful duo of complementary tools

One of the most remarkable features of bats is their ability to combine or switch between echolocation and vision. While echolocation is their primary tool for avoiding obstacles in complete darkness and hunting, their eyes provide critical supplementary information.

When do bats rely on vision? Bats use their vision extensively during moonlit nights and twilight when there is enough light to navigate visually. Fruit bats, which do not echolocate, rely entirely on their vision to avoid predators and find food.

How do bats integrate both senses? For microbats, echolocation and vision work in tandem. Echolocation gives them detailed three-dimensional information about their surroundings while their eyes help them gauge distances and recognise landmarks. This dual capability is particularly important during long migrations or when navigating through complex landscapes.

How bat's echolocation works

A common misconception is that bats use echolocation instead of vision. In reality, bats use both senses, often complementing each other depending on the situation.

Echolocation – This is a sophisticated biological sonar that involves emitting high-frequency sound waves and interpreting the returning echoes to detect objects, obstacles and prey. Echolocation is highly effective in complete darkness or complex environments. Think of it as their built-in GPS.

Vision – While echolocation is precise, it has limitations esp. in detecting stationary objects or over long distances. Vision fills these gaps by enabling bats to identify food sources during moonlight or twilight, orient themselves and recognise landmarks.

Fun fact – Some bats’ echolocation is so precise they can detect a tiny insect’s wing flutter from metres away. Combine this with sharp vision and you have a creature that’s practically a superhero of the animal kingdom.

Appreciation, conservation and understanding of bat vision

Understanding the truth about bats’ vision is crucial for their conservation. Many bat species face threats from climate change, habitat loss and human activities. Dispelling myths can foster a greater appreciation for their ecological importance and encourage efforts to protect them. Understanding bat vision is not just a matter of correcting a myth but it has real-world implications for conservation. As humans encroach on natural habitats and introduce artificial lighting, bats face significant challenges. Excessive light pollution can disorient bats and disrupt their natural behaviours including breeding and hunting.

For instance, bats play a critical role in agriculture by controlling pest populations and pollinating crops like agave (used to make tequila), bananas and mangoes. Recognising their contributions helps shift the narrative from fear to fascination. By knowing that bats rely on both their echolocation and vision, conservationists can take steps to mitigate the impact of artificial lighting. For example, using bat-friendly lighting or preserving dark corridors in urban areas can help ensure that bats continue to thrive.

Conclusion | Final thoughts

The notion that bats are blind is a myth that has persisted far too long. Bats are extraordinary creatures with a unique blend of senses that allow them to hunt, navigate and survive in diverse environments. Their vision is far from being redundant. From echolocation to low-light vision and UV sensitivity, these creatures have evolved to thrive in their environments with unparalleled efficiency. It is a vital part of their sensory toolkit. By dispelling the myth of bat blindness, we can foster a deeper appreciation for these fascinating mammals. As we learn more about bats, it becomes evident that they are not only fascinating but also essential to the balance of nature. By debunking myths and embracing the science, we can pave the way for a future where bats are celebrated rather than misunderstood.

We ought to encourage the efforts to protect their habitats. So, the next time you hear someone say ‘blind as a bat’ feel free to confidently set the record straight that...