Apotheosis episode 29: How to see like a bat. We don't actually see the world as it is, but rather we see an image of the world generated by our brains.

Episode 29: How to see like a bat

Ryan D Thompson Biology, Complexity, Modern, Neuroscience, Skills

Key ideas

Every organism occupies its own unique sensory world, arising from the combination of sensory apparatuses it possesses. We can never truly know what it’s like to perceive the world through the “eyes” of another being.

  • Imagine being in the depths of a cave. You can hear the water dripping, feel slippery rock under your feet, and smell the guano. But you can’t see a thing. Your eyes can’t gather information in the total darkness of the cave. Where you suffer, though, other animals thrive.
  • In this same environment, cave-dwelling bats, spiders, salamanders, snails, and crickets have an entirely different experience. Their sensory apparatuses allow them to perceive details we cannot. These unique sensory experiences demonstrate a concept in biology called “umwelt.”
  • All sentient beings have an individual, subjective experience of their environment. You, me, and other humans – along with every cat, dog, snail, lizard, fish, or any other sentient being, for that matter – we are all subjects, the protagonists in our own stories. Our umwelt.
  • Each living being (or at least every human) sees its own reality as the “right” view. But this is just a mental bias. Just because we have a picture of the world in our brains, that doesn’t mean we have the most accurate picture of our environment. What might we be missing?


You wake up in the dark, hanging by your feet. You hear and feel the twitching of leathery wings all around you. Water drips slowly from the roof, each drip echoing off rocky walls, every echo forming a map of the cave. Driven by hunger, you spread your wings and take flight, following a trail of bats out into the night sky. You see movement ahead, the fluttering of tiny wings. Click, click, click click click. You send out sonar to zero in on your prey’s location. Click click clickclickclick in increasing frequency, and then, gulp! A delicious moth for dinner.

As fun as this thought experiment was, the fact is that we can’t ever know what it’s truly like to see the world through the eyes – and ears – of a bat. Except for some visually impaired humans who have learned the art of echolocation, most of us will never be able to comprehend what it’s like to quote-unquote see with sonar. We lack the sensory apparatus for experiencing the world in this way.

Despite occupying the same space, every creature in that space enjoys a distinct and unique experience of its environment. The same air, the same light, temperature, and configuration of molecules, the same gathering of species. But each creature – including us humans – sees, hears, tastes, feels, and otherwise senses the world around them differently. 

This episode will explore this unique sensory world that all creatures occupy, looking at a concept from biology called “umwelt.” By looking at the myriad ways of experiencing the world, we can hopefully gain insight into how we can see the world in a whole new light – or no light.

Nearly a century ago, a German biologist named Jakob von Uexküll applied the term “umwelt,” which means “environment” or “surroundings,” to describe how organisms perceive the world – their unique sensory world. Umwelt is often described as the “self-centered world.” In other words, all beings have an individual, subjective experience of their environment. You, me, and other humans – along with every cat, dog, snail, lizard, fish, or any other sentient being, for that matter – we are all subjects, the protagonists in our own stories. “Me, myself, and I” interacting with the world outside. 

Exactly how we experience the world depends on the sensory apparatuses we have. Each creature perceives its environment through the combination of visual, auditory, tactile, electromagnetic, or other sensory inputs wired into its brain (or whatever nervous system it possesses).

And many of these sensory perceptions are beyond our comprehension. We might imagine what it’s like to use echolocation like a bat, but we’ll never know. We can’t know what it’s like to use infrared detectors to stalk prey like a pit viper. Or to sense electrical fields like a shark uses as it zeroes in on a kill. We lack sensory apparatus to detect the earth’s magnetic fields, so we can’t understand the world of the honeybee, which uses geomagnetic signals to find its way home. As anyone with a dog knows, we miss out on a wide range of sounds, perhaps for the better, so we’re not constantly barking at the window. Likewise, we can’t know what it’s like to experience the vastly expanded world of smell that dogs use to track what’s happening around them. Also, for the better, since dogs tend to shove their sniffers in places we humans prefer not to smell.

Even within the realm of human perception, we can see different umwelt. For example, I’m one of the 1 in 12 men who are colorblind. For me, it’s mostly brown, red, and green that tend to throw me off. I see some browns as reds or as greens. Which made for all kinds of trouble picking out clothes when I was growing up. So that’s one umwelt: if you’ve never seen through colorblind eyes, nothing I can tell you can make you experience color blindness. Just like I have no idea what it’s like to see color through your eyes.

Now, on the flip side, some women can see millions more colors than the average human. Like in some cases, around 99 million more colors. These women (and only women so far as I understand), called “tetrachromats,” have an additional color receptor in their eyes. So just as you were rejoicing in your ability to see more color than I can, here comes someone else who can see even more color.

So on one end of the spectrum, we have people like me with deficient color perception. On the other end, women with vastly greater color perception. And then somewhere in the middle, you. We all see color the way we see it – and can’t comprehend what it’s like to see color any other way.

This case points to another interesting concept related to umwelt – the idea of objective reality. Since we’re the subject of our self-centered story, we see and tell that story through our own eyes. Thus we favor our perceptions as being the “right” ones. But this is just a mental bias. Just because we have a picture of the world in our brains, that doesn’t mean we have the most accurate or helpful picture all the time. 

For example, humans lack the ability to smell underwater. Sharks, however, can smell blood molecules from several miles away. So if you happen to be in the water with a few drops of blood floating nearby, you would have no idea – meanwhile, some sharks are just cruising their fins right over your way. Or another example, during the massive tsunami that hit Asia in 2004, animals were reported to flee for high ground well before humans had any idea what was coming. Theories I’ve read suggest that the animals detected vibrational waves from the epicenter of the quake causing the tsunami.

I find this to be an absolutely fascinating concept. We trust in the evidence of our senses, believing without question that what we see is the objective reality. But we’re looking through a lens of our limited sensory apparatuses. What would happen if we swapped out our eyes, ears, and nose for antennae or electroreceptors? Would we still think, feel, and believe the same as we do now?

Let’s add another layer to this story. The traditional idea of umwelt refers to sensory perception of the environment. However, at least with humans, there would seem to be another step in the process of perception. Take a moment to look around at the space you’re in. You’re seeing the world, right? Not quite. Light waves hit your eyes and send a signal to your brain, producing an image based on what it interprets from those light waves. Along the way, those signals are passed back and forth to various brain regions to assess the information – is it a threat? Is it food? Anything of value? This process calls on past memories, knowledge, and beliefs. 

Thus, the image you believe is a snapshot of the “real” world is actually seen through a filter of your unique life experiences. Think about that for a moment: we don’t actually see the world as it is, but rather we see an image of the world generated by our brains. Our own subjective world.

This at least partially explains how miscommunication can happen – how a group of people can be in the same room and experience the same event – but then each person walks away with a totally different understanding of what happened. We see, hear, and feel the world through our own lens.

Contemplating this idea of a distinct umwelt for every human – or every sentient being – certainly has the potential to help us soften our views. It can help us to expand our understanding of what is “right” or “true” in a given situation. Recognizing that our perceptions arise from the sensory apparatuses available to us and are further colored by experience, we can take a more objective view of the world. We can ask ourselves: What am I missing? How can I find out?

Understanding umwelt also helps give us a greater respect for the subjective experience of other humans and the entire living world. Every living being has its own umwelt. Each of those unique experiences provides a different view of the world. What an awe-inspiring concept: like a kaleidoscope of consciousness, with each being creating a tapestry of perception.

Well, that’s all for now. I hope you enjoy your unique sensory world this week. In the meantime, I have a favor to ask. If you can leave a review or a rating for this podcast on Apple Podcasts or Spotify, that would really help me reach more people with these ideas. And this week marks one year since I launched the podcast, so I’ll be putting together some content to review some highlights of things I’ve learned. Connect with me on LinkedIn or check the Project Indra website for more info. Until the next time, be well!

Further reading:

Podcast soundtrack credit:

Our Story Begins Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0 License