DARWIN’S EARTHWORMS

Charles Darwin may be best known for his theory of evolution by natural selection, but he was also a massive earthworm enthusiast. He performed experiments, spanning decades, to work out the rate at which worms recycle the soil, and observed their knack for carefully interring leaves, pointed end first. He tested their food preferences by feeding them cherries and carrots, and their hearing by shouting at them and playing them the bassoon. He chronicled his findings in the last book he ever wrote, which he called The Formation of Vegetable Mould through the Action of Worms, with Observations of their Habits. Published in 1881, the annelid opus was an instant hit, even outselling Darwin’s best-known book, On the Origin of Species, during his lifetime.