An Immense World: How Animal Senses Reveal the Hidden Realms Around Us

by Ed Yong

The senses transform the coursing chaos of the world into perceptions and experiences—things we can react to and act upon. They allow biology to tame physics. They turn stimuli into information. They pull relevance from randomness, and weave meaning from miscellany. They connect animals to their surroundings. And they connect animals to each other via expressions, displays, gestures, calls, and currents.

Nothing can sense everything, and nothing needs to. That is why Umwelten exist at all. It is also why the act of contemplating the Umwelt of another creature is so deeply human and so utterly profound. Our senses filter in what we need. We must choose to learn about the rest.

Perhaps people who experience the world in ways that are considered atypical have an intuitive feeling for the limits of typicality.

The Umwelt concept can feel constrictive because it implies that every creature is trapped within the house of its senses. But to me, the idea is wonderfully expansive. It tells us that all is not as it seems and that everything we experience is but a filtered version of everything that we could experience. It reminds us that there is light in darkness, noise in silence, richness in nothingness. It hints at flickers of the unfamiliar in the familiar, of the extraordinary in the everyday, of magnificence in mundanity. It shows us that clipping a microphone onto a plant can be an intrepid act of exploration.

We should be skeptical of any claim that pits one animal’s sense of smell against another’s. I have repeatedly read that an elephant’s sense of smell is five times more sensitive than a bloodhound’s, but that’s an utterly meaningless statement. Does that mean the elephant detects five times more chemicals? Does it sense certain chemicals at a fifth the concentration, or from five times the distance? Does it remember smells for five times as long? Such comparisons will always be flawed because smell is diverse and often unquantifiable.

The sun periodically throws cosmic tantrums and produces solar storms—streams of radiation and charged particles that affect Earth’s magnetic field. Such storms could conceivably mess up the compasses of magnetically sensitive whales, and if these animals are close to a shoreline, even a small navigational error might send them aground. To test this idea, Granger collated 33 years’ worth of records of healthy, uninjured gray whales inexplicably stranding themselves. She compared the timing of these incidents to data on solar activity, wrangled by her astronomer colleague Lucianne Walkowicz. A striking pattern emerged: On days with the most intense solar storms, gray whales were four times more likely to beach themselves.[*5]

How can we possibly know what it is like to be an octopus? Its unusual senses challenge our imagination, but so does the way it brings those senses together. Its component threads are unfamiliar, the weave is exotic, and the tapestry that results is utterly alien.