Even the most familiar of settings can feel newly unfamiliar through the senses of other creatures. I walk my dog — Typo, a corgi — three times a day, passing the same streets and buildings that I’ve seen thousands of times. But though this urban landscape seems boring and stagnant to my eyes, its smellscape is constantly fascinating to Typo’s nose. He sniffs constantly, his nasal anatomy allowing him to continuously draw in odors even while exhaling. He sniffs the individual leaves of emergent springtime plants with utmost delicacy. He sniffs patches of dried urine left behind by the neighborhood dogs — the equivalent of a human scrolling through a social media feed. On every walk, there’ll be at least one moment when Typo grinds to a halt and excitedly explores a patch of sidewalk that looks nondescript but is clearly bursting with enthralling odors. By watching him, I feel less inured to my own life, more aware of the perpetually changing environment around me. Such awareness is a gift, which Typo gives to me daily.
These sensory worlds can be difficult, and sometimes impossible, for nature documentaries to capture (although some, like Netflix’s “Night on Earth,” make a valiant effort). No special effects can truly convey the wraparound nature of bird vision to the front-facing eyes of a human viewer or translate the wide spectrum of colors visible to a bird into the much narrower set that our eyes can see. Nonvisual senses are even harder for a visual medium to capture. You can play recordings of a whale’s song, but that doesn’t show what it means for whales to hear each other across oceanic distances. You can depict the magnetic field that envelops the planet, but that can’t begin to capture the experience of a robin using that field to fly across a continent.
In his classic 1974 essay, “What Is It Like to Be a Bat?” the philosopher Thomas Nagel wrote that the conscious experiences of other animals are inherently subjective and hard to describe. You could envision yourself with webbing on your arms or insects in your mouth, but you’d still be creating a mental caricature of you as a bat. “I want to know what it is like for a bat to be a bat,” Dr. Nagel wrote. Most bat species perceive the world through sonar, sensing their surroundings by listening for the echoes of their own ultrasonic calls. “Yet if I try to imagine this, I am restricted to the resources of my own mind, and those resources are inadequate to the task,” Dr. Nagel wrote.
Our own senses constrain us, creating a permanent divide between our Umwelt and another animal’s. Technology can help to bridge that chasm, but there will always be a gap. Crossing it requires what the psychologist Alexandra Horowitz calls “an informed imaginative leap.” You cannot be shown what another Umwelt is like; you must work to imagine it.
Watching modern nature documentaries has almost become too easy, as if I am being passively swept away by the torrent of vivid imagery — eyes open, jaw agape, but brain relaxed. By contrast, when I think about other Umwelten, I feel my mind flexing and the joy of an impossible task nevertheless attempted. In these small acts of empathy, I understand other animals more deeply — not as fuzzy, feathered proxies for my life, but as wondrous and unique entities of their own, and as the keys to grasping the true immensity of the world.