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 half centimetres of metallic green with shimmering red thighs, the wasp is also a killer.
It possesses a sting with a touch-sensitive tip that it can insert into the midsection of a much larger cockroach prey. This injection briefly paralyses the victim’s locomotion centre, but a second sting fired into the roach’s brain tranquillises it for the rest of its short life. In the state of a “submissive zombie”, the roach will attend the wasp’s lair to serve as fresh protein for the jewel wasp’s progeny. Such is the wasp’s control of its victim that it can use its antennae to lead the roach along, much as a human might walk a dog.
The wasp’s stinger is so sensitised to the task that it can locate the exact cluster of neurons amid the tangle of muscle and organ inside a cockroach’s minuscule head. Experiments have shown that if the victim’s brain is removed, or substituted with a pellet, the wasp senses that something is amiss even when the replacement deviates only a little in its texture from the true organ. In short, the wasp’s sense of touch is astonishing.
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This is just one of myriad stories that Ed Yong, a British science writer for the Atlantic magazine, has assembled to illuminate the variety of behaviours pursued by the Earth’s occupants. Yet the author’s primary goal is more refined than a simple bestiary. He seeks to offer his reader a panoramic, complex portrait of the sensory capacities that underpin a multitude of life ways.
Here are great whales, whose low-frequency song is so adjusted to the sonic resonances of the open ocean that the vocalists can be heard by other whales halfway round the planet. Here are trails created by leafcutter ants, through a deposition of chemicals from glands in gut and limb, which fellow ants pinpoint with such accuracy that a single microgram of pheromone, laid with maximum efficiency, would be sufficient to create a trail stretching three times around the world. Alas for some ants, if the trail should ever form a complete circle, the poor insects can become chemically trapped and go round and round until they expire.
Chapter by chapter, the author builds an understanding of how each of the primary human senses – smell, taste, sight, hearing, touch – operate in other species. But Yong also delves into sensory experiences beyond our ken, which modern science is beginning to uncover. One of these is an ability of migrating turtles and birds to detect the Earth’s geomagnetic field and to utilise it as a navigation tool in their world-wrapping journeys. The Earth’s molten metal core and the creatures’ visual senses are in some, as yet inexplicable, manner, connected.
Yong explains his underlying purpose by using a vocabulary developed by Jakob von Uexküll, a Baltic-German zoologist and philosopher in the early 20th century. Uexküll popularised the concept that, while we may share physical space with animals, their inner sensory experience of that same geography is radically distinct. Uexküll called the perceptual capsule in which each species dwells its Umwelt. He proposed the idea partly to underscore that our sensory interpretation of life was merely one among a multitude. It was also intended to challenge the anthropocentric assumptions that were at the root of so much human behaviour and thought.
In a book that grows into a literary rainforest of other animals’ perceptual experiences, it is hard to pick out individual stories. Yet I particularly loved Yong’s brilliant description of the auditory powers possessed by most of the world’s 1,400 bat species. These gifts underpin the bat family’s ability for echolocation, which is truly one of the marvels of animal evolution. In effect, bats blitz their world in volleys of loud ultrasonic calls (thankfully beyond our audible range). Bats are then drenched in a returning barrage of their own echoing sounds, and from these their own neurological apparatus distils an interior picture of their physical surroundings.
It was as long ago as the 18th century that an Italian priest, Lazzaro Spallanzani, formulated the improbable concept that a bat’s hearing was somehow essential to its ability to “see”. It took a further 150 years before the American biologist Donald Griffin worked out how bats navigated, and located their insect prey, sometimes in conditions of total darkness. Yong’s unfolding of these processes is a model of writerly precision and clarity that renders the technical complexities in a manner easy for the lay person to grasp.
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There is a double moral purpose to his book, which Yong outlines in a long conclusion. Trapped within our own Umwelt, humans are slow to grasp how our behaviours increasingly fragment the perceptual worlds of our fellow citizens. One tiny example is a memorial event intended to honour those murdered at New York’s Twin Towers in September 2001. Every year, utilising 88 xenon bulbs, each with an intensity of 7,000 watts, the organisers fire a so-called Tribute in Light into the night sky, which can be seen from 100 kilometres away. Alas, mid-September just happens to be the peak period for migrating birds, and lights of this nature can have a huge impact on the avian navigational process. Across seven nights of its operation, the Tribute in Light has been proven to waylay more than one million birds.
Excessive light is now understood to be as serious in its effects as other forms of pollution, with the area that is now affected worldwide increasing by 2 per cent every year. Noise is as serious an issue, with all but 14 per cent of America within just a kilometre of a road. You begin to see how Yong’s insistence upon this concept of the Umwelt starts to shape a new understanding of issues. Imprisoned within our diurnal indifference to night light or to the horrendous noises of the mechanosphere, humans fail to grasp that which they do.
Yet Yong makes an even more important point that is implicit in the whole text. It has particular resonance at this specific moment. In a post-lockdown world, we have been assailed by public messages, even from environmentalists, telling us how effective nature is as a safety valve for the travails 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 shall have dominion over everything upon Earth. Both converge in the idea that nature is instrumental to our purposes. It exists to meet our needs.
What this book does is turn that world-view inside out. Yong’s excursion into the extraordinarily complex interior lives of so many creatures – insects, turtles, finches, robins, elephants, sharks, octopuses, whales and jewel wasps – shows us that there is an entire universe of unfathomable beauty all around us.
It is not ours. But we can share it. Not since Oliver Morton’s masterpiece of popular science Eating the Sun (2007) has a book so persuasively made the case that the Earth is greater than we know. As Yong writes, “Wonder exists in a backyard garden… Wilderness is not distant. We are continually immersed in it. It is there for us to imagine, to savour, and to protect.”
An Immense World: How Animal Senses Reveal the Hidden Realms Around Us
Ed Yong
Bodley Head, 464pp, £20
Mark Cocker’s most recent book is “A Claxton Diary: Further Field Notes from a Small Planet” (Vintage)
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This article appears in the 06 Jul 2022 issue of the New Statesman, The Last Days of Boris Johnson