Science Natural Science World's Largest Earthworm Can Grow to 9-Feet Long Found only in a single river valley in southeast Australia, these rare, giant earthworms grow large and live long. By Kimberley Mok Kimberley Mok Twitter Writer McGill University Cornell University Kimberley Mok is a former architect who has been covering architecture and the arts for Treehugger since 2007. Learn about our editorial process Updated March 31, 2022 Share Twitter Pinterest Email Biodiversity Heritage Library / Flickr / Public Domain / Getty Images Science Space Natural Science Technology Agriculture Energy Living underground and mostly out of sight, squiggly earthworms seem like such humble, mundane organisms. That is unless it's Australia's giant Gippsland earthworm, which is believed to be the world's largest species of worm. Native to southeastern state of Victoria, and found only in the Bass River Valley of South Gippsland, the giant Gippsland worm (Megascolides australis) measures on average 3.3 feet (1 meter) long, and 0.79 inches (2 centimeters) in diameter and weighs about 0.44 lbs (200 grams). However, these long-lived invertebrates can survive up to 5 years or more, maturing to a whopping 9.8 feet (3 meters) in length. Issy / iNaturalist / CC-BY-4 “They live underground and have so many secrets,” Dr. B. D Van Praagh of the Building Capability to Manage Giant Gippsland Earthworm Habitat on Farms organization tells Ripley's. “It’s hard to get past their size; although often exaggerated, they are huge." The giant Gippsland thrives best in clayey, wet subsoils of river banks, burrowing deep to create its networked habitats. Unlike their smaller cousins, which come to the surface to defecate, the giant Gippsland deposits its castings underground, relying on heavy rains to flush out the waste from its burrows. Highly sensitive to aboveground vibrations, the giant Gippsland responds to unknown intruders' footsteps by moving away. They are so big that this movement produces audible squelching noises that can be heard on the surface. M. australis is currently classified as a protected species, its numbers having been reduced by the introduction of agriculture into this region of Australia. Other limiting factors include its low rate of reproduction and slow development; the worm produces one large egg capsule just under three inches long, which takes one year to incubate into a single offspring. In honor of this remarkable and rare earthworm, locals in the town of Korumburra hold an annual worm festival with parades, games, and the crowning of an earthworm queen. Forget those overblown sci-fi sandworms—these giants are the real deal on Earth.