October 21 marks World Earthworm Day, an occasion to celebrate an animal that is emblematic of healthy soil and responsible for its fertility. Céline Pelosi, geodrilologist (earthworm specialist) and director of soil ecology research at the French public research institute INRAE, introduces us to this shadowy animal. She warns us about conventional farming practices (ploughing, use of pesticides, etc.), but also about climate change, which is putting earthworms and our soils at great risk. IMAGES AND SOUNDBITES