A World of Sensory Bubbles

While recent developments in artificial intelligence are leading to projections of a future in which human beings will be more and more altered by technology, some natural scientists have been trying to understand more about other sentient beings with whom we share the planet.  Their discoveries offer hope that our species might yet find an alternative to the trajectory that seems almost certain to lead us into extinction.

Ed Yong, a science writer, described some of this exciting work in An Immense World – How Animal Senses Reveal the Hidden Realms Around Us (2022). Yong aims to understand how animals other than humans perceive their immediate environment.

He explains:

Earth teems with sights and textures, sounds and vibrations, smells and tastes, electric and magnetic fields. But every animal can only tap into a small fraction of reality’s fullness. Each is enclosed in its own sensory bubble, perceiving but a tiny sliver of an immense world.

That bubble is an animal’s perceptual world, its Umwelt. While the word Umwelt generally means  “environment” in German, it was defined in 1909 by Jakob von Uexkuell, a Baltic German biologist, as a living being’s surroundings as perceived through its senses. He pointed out that the small, wingless tick, for example, has no eyes, it’s blind. It finds its way to its food source, the blood of warm-blooded animals, through its sensitivity to light and temperature. It may wait for a long time on a tree branch for a warm-blooded animal (such as a mouse, dog, or human, for example) to pass below. When it does, the tick drops down on the animal.

We humans navigate mostly on sight. Our sensory bubble does not include the tick’s sensitivity to  butyric acid, which emanates from warm-blooded animals. We also can’t hear the ultrasonic calls of mice or hummingbirds, or sense magnetic fields as turtles do.

Yong seeks to understand what it is like to be these animals. To experience that is surely impossible, we are limited by our own sensory bubble,  but Yong describes  research on a wide variety of animals, ranging from the most familiar to the wildly exotic, that reveals how they make their way in our shared world.

Take the dog. Everyone knows that dogs have an acute sense of smell, far better than we humans do, and that they detect odors through their nostrils, as we do. But a dog’s olfactory system is far more developed. When we humans exhale, we release the smells we inhaled, while in dogs odorants that entered the nose tend to stay there, replenished by every sniff. As dogs exhale, side-facing slits in their nostrils allow more smells to waft into their noses. We lack such slits. Dogs are constantly exploring what interests them, although we may think they are randomly wandering. What the human calls a walk is a sniffing expedition for the dog. A dog-walker who does not allow sniffing is depriving that dog of an essential experience. That’s useful information if you want a good relationship with a dog.

While a dog relies on the sense of smell, and vision is the dominant sense of perception for humans, Yong writes, animals perceive their Umwelten in many other ways. The star-nosed mole, a truly bizarre-looking creature (from my human perspective), that lives in tunnels it digs in bogs and swamps, and navigates by means of the sense of touch. Star-nosed mole  habitat includes the eastern part of North America, including densely populated areas, but it is seldom seen, Yong reports, because it’s mostly underground.

Yong describes it as  roughly the size of a hamster, with silky fur and a rat-like tail, and, on its snout, eleven pairs of “pink, hairless, finger-like appendages arranged in a ring around its nostrils.” Under a microscope, bumps can be seen on these appendages. The animal presses the bumps rapidly  as it moves along, feeling its way as human beings might use their hands to find their way through a dark house. One pair the appendages, smaller than the rest, is used exclusively for taking in food.

Even as many species have perished because of habitat destruction and pollution, more continue to be discovered. Scientists continue to be surprised by animals we thought we knew. Chimpanzees watch sunsets and waterfalls, apparently entranced. Just recently, I read of research that indicates that elephants may call each other by name. After an elephant dies, family members gather for a ceremony. More and more, we discover how we are kin with other animals, different but related. At some point, we will have to acknowledge the others also have a right to exist.

An estimated two million species live in the largely unknown world of the oceans, but only ten percent of these have been identified. The darkness in the deep ocean is home to the giant squid, which has eyes the size of a soccer ball, twice that of a blue whale. Why? As eyes get bigger, the gain in vision yields diminishing returns. Well, those huge eyes can detect a sperm whale—not the whale itself but the flashes of bioluminescent small jellyfish and crustaceans, which reveal the presence of the sperm whale, which preys on the giant squid.

Research of the kind Yong describes expands our awareness of ourselves in context of the planetary community. This research is not anthropocentric, unlike studies that aim to show that other animals can be taught to do what humans do—chimpanzees to play cards, for example. Rather than trying to prove whether certain animals are intelligent (whatever that may mean) in comparison to us humans, some scientists are now trying to get to know other animals as they experience their lives. Even as we, the  humans species, are driving ourselves toward a dead end by our inventions, progress is being made toward a humbler understanding of our life on this planet as one of uncounted beings, all here together in different perceptual worlds.