Charles Darwin named it perhaps the most important creature on earth – because without it, our soil would wither away.

It is one of the early highlights of biology studies: first-year students explore the anatomy of the earthworm with a scalpel, magnifying glass and tweezers. The interior of Lumbricus terrestris is amazingly organized and surprisingly diverse. Five ring-shaped hearts wind around the throat, pumping blood through the worm. There are testicles and ovaries—the beasts are male and female at the same time—and kidney-like organs called nephridia. Everything is encased by longitudinal and circular muscles, thanks to which the blind bottom dweller digs through the ground.

Earthworms are male and female at the same time