Fish that swim backwards – and other natural wonders

In the Zhuangzi, a collection of tales attributed to the eponymous 4th-century BC Chinese philosopher, a frog that lives in a well boasts about its comfortable way of life to a visiting sea turtle. When the turtle describes its own existence in the vast expanse of the ocean, however, the frog has no idea what to make of it. The story is, of course, a humorous parable about typical human limitations and the possibility of stepping beyond them. But it could serve almost as well as an introduction to Ed Yong’s new book, which confirms in rich detail what Zhuangzi intuited: the nature and range of different forms of animal perception is astounding, and a greater appreciation of them has the potential to enrich human life.

Yong, a staff writer for the Atlantic magazine and the winner of a Pulitzer Prize last year for his reporting on Covid-19, is the author of I Contain Multitudes, a guide to the micro-biome – that is, the diversity of microbial life on which humans and other animals depend. The book, published in 2017 and based on extensive interviews and field visits as well as historical research, explored remarkable discoveries right up to the cutting edge of science. It was characterised by efficient, witty prose and a sense of fascination and delight – a hallmark technique that has become known as ‘Ed-splaining’ – and was a popular- science bestseller. An Immense World applies the same formula to what looks likely to be comparable effect.

So we read that a fourth type of cone cell in the eyes of hummingbirds unlocks an entirely new dimension of colour, including UV-red, UV-green, UV-yellow and UV-purple – which Yong felicitously names ‘rurple’, ‘grurple’, ‘yurple’ and ‘ultra-purple’; that by sending vibrations through plant stems, insects called treehoppers make a mating call as low as that of an alligator, even though they are less than a millionth their size; and that black ghost knifefish swim backwards with confidence, thanks to a wraparound sense of electrolocation.