When there is plenty of rain, earthworms are generally out and about, mating and making our soils fertile. During the dry season they enter a state of anabiose during which they either migrate deeper into the soil, roll into a ball and โsleepโ or they become less active in the leaf litter, if they are leaf litter species. When the rain is delayed, earthworms also delay coming out of their sleep until the conditions are favourable.
Swartberg is on the border of KwaZulu-Natal and Eastern Cape provinces. During the 2025โยญ2026 rainy season, Swartberg received less rain and interestingly, the sampling in December-February recovered earthworms that were still sleeping from the previous dry season. With winter fast approaching, one can only wonder if the sleeping beauties will make it to the next rainy season or if natural selection will play out! Sampling in the area continues and more data will paint a better picture on the effect of climate change on earthworms.
written by:
Dr Thembeka Nxele, the curator of Oligochaeta at the KwaZuluโNatal Museum, where she has been researching terrestrial earthworms for 15 years. She focuses on the taxonomy, distribution, and ecology of indigenous species, and is responsible for curating and maintaining the museumโs earthworm collection. Her research interests include systematics, biodiversity, conservation biology, biogeography, and genetics of indigenous earthworms.
A sleeping earthworm (b) was collected from a level deeper than a spade length (a). Local children helping with field work (c).
