The sound of an earthworm is a distinctive rasping and scrunching. Ants sound like the soothing patter of rain. A passing, tunnelling vole makes a noise like a squeaky dog’s toy repeatedly being chewed.

On a spring day at Rothamsted Research, an agricultural research institution in Hertfordshire, singing skylarks and the M1 motorway are competing for the airways. But the attention here is on the soundscapes underfoot: a rich ecosystem with its own alien sounds. More than half of the planet’s species live in the soil, and we are just starting to tune into what they are up to. Beetle larvae, millipedes, centipedes and woodlice have other sound signatures, and scientists are trying to decipher which sounds come from which creatures.