The emerald jewel wasp of tropical Africa, we are told in this remarkable and transformative book of popular science, is a real beauty. Two and a half centimeters of metallic green with shimmering red thighs, the wasp is also a killer.
It possesses a sting with a tactile tip that it can insert into the midsection of much larger cockroach prey. This injection briefly paralyzes the victim’s center of locomotion, but a second sting fired into the cockroach’s brain tranquilizes it for the rest of its short life. In the “submissive zombie” state, the roach will travel to the wasp’s lair to serve as fresh protein to the offspring of the jewel wasp. The wasp’s control over its victim is such that it can use its antennae to guide the cockroach, much like a human might walk a dog.
The wasp’s stinger is so sensitized to the task that it can locate the exact cluster of neurons amidst the tangle of muscles and organs inside a cockroach’s tiny head. Experiments have shown that if the victim’s brain is removed or replaced with a pellet, the wasp senses that something is wrong even when the replacement deviates only slightly in texture from the real organ. In short, the wasp’s sense of touch is amazing.
[See also: Remaking the Anthropocene]
This is just one of the myriad stories that Ed Yong, a British science writer for the Atlantic magazine, came together to illuminate the variety of behaviors pursued by the occupants of Earth. However, the primary objective of the author is more refined than a simple bestiary. It seeks to offer its reader a panoramic and complex portrait of the sensory capacities that underlie a multitude of lifestyles.
Here are large whales, whose low-frequency song is so tuned to the sound resonances of the open ocean that the songs can be heard by other whales on the other side of the planet. Here are trails created by leafcutter ants, through deposition of chemicals from glands in the gut and limbs, which other ants identify with such precision that a single microgram of pheromone, deposited with such efficiency maximum, would be enough to create a path extending three times around the world. Alas for some ants, if the trail should ever form a full circle, the poor insects can be chemically trapped and run in circles until they expire.
Chapter by chapter, the author builds an understanding of how each of the primary human senses – smell, taste, sight, hearing, touch – function in other species. But Yong also delves into sensory experiences beyond our knowledge, which modern science is beginning to uncover. One is the ability of turtles and migrating birds to sense the Earth’s geomagnetic field and use it as a navigational tool in their journeys around the world. Earth’s molten metal core and creatures’ visual senses are connected in ways that have yet to be explained.
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Yong explains his underlying purpose using vocabulary developed by Jakob von Uexküll, an early 20th-century Baltic-German zoologist and philosopher. Uexküll popularized the concept that although we may share physical space with animals, their inner sensory experience of that same geography is radically different. Uexküll called the perceptual capsule in which each species inhabits its Umwelt. He came up with the idea in part to emphasize that our sensory interpretation of life was just one of many. It also aimed to challenge the anthropocentric assumptions that were at the root of so much human behavior and thought.
In a book that turns into a literary rainforest of other animals’ perceptual experiences, it’s hard to pick out individual stories. Still, I particularly liked Yong’s brilliant description of the auditory powers possessed by most of the world’s 1,400 species of bats. These gifts underpin the bat family’s ability to echolocate, which is truly one of the marvels of animal evolution. Indeed, bats blitz their world in volleys of loud ultrasonic calls (thankfully beyond our audible range). The bats are then drenched in a barrage of feedback from their own echoing sounds, and from these, their own neurological apparatus distills an inner picture of their physical surroundings.
It was as early as the 18th century that an Italian priest, Lazzaro Spallanzani, formulated the unlikely concept that a bat’s hearing was somehow essential to its ability to “see.” It took another 150 years before American biologist Donald Griffin understood how bats navigated and located their insect prey, sometimes in conditions of total darkness. Yong’s deployment of these processes is a model of precision and clarity of writing that renders the technical complexities in a way that is easy for the layman to grasp.
[See also: Utopia in the age of climate crisis]
There is a dual moral purpose to her book, which Yong outlines in a lengthy conclusion. Trapped in ours Umwelt, humans are slow to grasp how our behaviors are increasingly fragmenting the perceptive universes of our fellow citizens. A small example is a memorial event to honor those murdered in New York’s Twin Towers in September 2001. Each year, using 88 xenon bulbs, each rated at 7,000 watts, organizers launch a so- saying Tribute in Light in the night. sky visible 100 kilometers away. Alas, mid-September happens to be peak time for migrating birds, and lights of this nature can have a huge impact on the avian browsing process. During her seven nights of operation, the Tribute in Light has been proven to track over a million birds.
Excess light is now considered to have effects as severe as other forms of pollution, with the area currently affected worldwide increasing by 2% each year. Noise is an equally serious issue, with all but 14% of America within a mile of a road. You begin to see how Yong’s insistence on this concept of Umwelt begins to shape a new understanding of the issues. Trapped in our daytime indifference to nighttime light or the awful sounds of the mechanosphere, humans don’t know what they’re doing.
Yet Yong makes an even more important point that is implicit throughout the text. It has a particular resonance at this precise moment. In a post-lockdown world, we have been bombarded with public messages, even from environmentalists, telling us how effective nature is as a safety valve for the hardships of a Covid-afflicted world. I really don’t see too much distinction between a message telling us how great nature is for our well-being and the biblical concept that man should rule over everything on Earth. Both converge on the idea that nature is instrumental to our ends. It exists to meet our needs.
What this book does is turn that worldview on its head. Yong’s excursion into the extraordinarily complex inner lives of so many creatures – insects, turtles, finches, robins, elephants, sharks, octopuses, whales and jewel wasps – shows us that there is a whole universe of unfathomable all around us.
It’s not ours. But we can share it. Not since Oliver Morton’s popular science masterpiece eat sun (2007) has a book that demonstrated so convincingly that the Earth is bigger than we know. As Yong writes, “Wonder exists in a backyard garden… Wilderness is not far away. We are continually immersed in it. It is there for us to imagine, savor and protect.
A Huge World: How Animal Senses Reveal the Hidden Realms Around Us
Bodley Head, 464 pages, £20
Mark Cocker’s most recent book is “A Claxton Diary: Further Field Notes from a Small Planet” (Vintage)
[See also: Are extreme heatwaves the new normal?]