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

by Ed Yong

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. Stepping between Umwelten, or at least trying to, is like setting foot upon an alien planet. Uexküll

Senses that seem paranormal to us only appear this way because we are so limited and so painfully unaware of our limitations.

through the strange senses that animals use to detect the electric and magnetic fields that we cannot.

But, some pplcan

why sentience is: It’s the process of sorting perceptual experiences into self-generated and other-generated.”

Some scientists have suggested that schizophrenia is fundamentally a disorder of corollary discharges. People with the condition might experience hallucinations and delusions because they can’t distinguish their own inner speech from the voices around them. A failure to sort self from other might also explain some of schizophrenia’s stranger symptoms, like the ability to tickle yourself. Might there be schizophrenic elephantfish that can’t tell their own discharges from those of other fish? “It’s certainly possible,” Carlson tells me. “I would expect dramatically disrupted behavior.” *10 In humans, the central nervous system includes everything in the brain and spine, while the peripheral nervous system includes the nerves in our limbs, organs, and other body parts. But in the octopus, this distinction breaks down. The nerves in the brachial and sucker ganglia are very much part of the central nervous system, even though they exist in the arms. *11 Between them, each sucker ganglion and its corresponding brachial ganglion contain around 10,000 neurons. That’s roughly as many as in an entire leech or sea slug. A single octopus arm contains roughly as many neurons as a lobster. *12 In the 1950s and 1960s, Martin Wells removed large parts of the brain from some octopuses and showed that these “decerebrate” animals could still use their suckers to manipulate objects, open

In 2016, when the team updated their atlas, they found that the problem was even worse. By then, around 83 percent of people—and more than 99 percent of Americans and Europeans—were living under light-polluted skies. Every year, the proportion of the planet covered by artificial light gets 2 percent bigger and 2 percent brighter. A luminous fog now smothers a quarter of Earth’s surface and is thick enough in many places to blot out the stars. Over a third of humanity, and almost 80 percent of North Americans, can no longer see the Milky Way. “The thought of light traveling billions of years from distant galaxies only to be washed out in the last billionth of a second by the glow from the nearest strip mall depresses me no end,” vision scientist Sonke Johnsen once wrote.

almost 7 million birds a year die in the United States and Canada after flying into communication towers.[*2]

œWe too quickly forget that we don’t perceive the world in the same way as other species, and consequently, we ignore impacts that we shouldn’t,”

Many of the other planetary changes we have wrought have natural counterparts: Modern climate change is unquestionably the result of human influence, but the planet’s climate does change naturally over much slower timescales. Light at night, however, is a uniquely anthropogenic force. The daily and seasonal rhythms of bright and dark remained inviolate throughout all of evolutionary time—a 4-billion-year streak that began to falter in the nineteenth century. Astronomers and physicists were among the first to talk about light pollution, which dimmed their view of the stars. Biologists only started seriously paying attention

in the 2000s, Longcore

More than 83 percent of the continental United States lies within a kilometer of a road.

estimated 90 percent of seabirds eventually swallow

Our influence is not inherently destructive, but it is often homogenizing. In pushing out sensitive species that cannot abide our sensory onslaughts, we leave behind smaller and less diverse communities.

With every creature that vanishes, we lose a way of making sense of the world. Our sensory bubbles shield us from the knowledge of those losses. But they don’t protect us from the consequences.

A better understanding of the senses can show us how we’re defiling the natural world. It can also point to ways of saving it.

It showed what conservationists can accomplish by “seeing the world through the perceptions of the animals you’re trying to protect.”[*10]

In a multitude of ways, the pandemic revealed the problems that societies had come to tolerate and the changes they were actually prepared to make. It showed that sensory pollution can be reduced if people are sufficiently motivated. Such

pollution in the sea looks hideous and everyone is worried, but noise pollution in the sea is something we don’t experience, so no one’s up in arms about it,” Gordon tells me. We

team of Dutch scientists led by Kamiel Spoelstra discovered this pattern in 2017. In response, a neighborhood within the town of Nieuwkoop, which sits next to a nature reserve, switched