A reader wrote to us a while back about a large earthworm he has been seeing in his shed as of late. He’s confident it’s an earthworm, but he was curious about its size; evidently, the earthworm is quite big – he estimates it to be about a foot (30 centimeters) long and the width of a pencil – and his family is skeptical of what he claims to be seeing. (The reader’s family is calling him “nuts,” more precisely.) The creature is hard to spot because it rarely comes out of the ground, so he hasn’t been able to get a photograph of it yet. The reader asked if we can supply any relevant information. We can, and the first thing to say is that our reader is in no way nuts: earthworms can get very big. Below is a basic overview of some of the huge earthworms out there, including the common Lumbricus terrestris, Glossoscolex giganteu, and Megascolides australis (a.k.a. giant Gippsland earthworm). All of the these worms reach impressive sizes, especially the last two.