One Of The Largest Earthworms On Earth Grows Up To 3 Meters And Makes Some Very Odd Sounds

Everything is stranger in Australia, at least when it comes to wildlife. Case in point: in a quiet corner of the country, the hills gurgle and slurp with the sounds of giant earthworms that are longer than a pool table.

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The giant Gippsland earthworm (Megascolides australis) averages around 1 meter (3.3 feet) in length with a girth of 2 centimeters (0.79 inches) – that’s about as long as a baseball bat and as chunky as a standard dinner candle. They can grow even bigger, though, with some individuals measuring up to 3 meters (9.9 feet) in length. 

This makes them one of the biggest species of earthworm on Earth, at least that we know of. There are around 6,000 named species of earthworm worldwide, although scientists believe there could be nearly 30,000 species, a huge number of which are hidden underground, away from nosy scientists. 

The African Giant Earthworm (Microchaetus rappi) is often awarded the title of the world's largest earthworm thanks to the discovery of one individual in 1967 that measured 6.7 meters (21 feet) in length. However, this case was exceptional, and the average length of this species is approximately 1.8 meters (6 feet).

You might assume that the size of the giant Gippsland earthworm means it's hard to miss, but these chunky worms are extremely elusive. They inhabit just five or so known locations in Gippsland, a region of southeastern Australia in Victoria, where the hills and creeks are filled with moist loamy soil. 

They look much like a common earthworm, albeit notably larger, chunkier, and with a slight purplish-grey hue. 

Like most worms, they spend most of their lives underground and are usually only seen on the surface when their tunnels become flushed out by rain or a flood. There’s an easy way to know they’re there, though: stomp the ground and you might hear a slurping, squelching noise beneath your feet (you can hear this in the video below). That sound is them evading trouble and squirming deeper into the waterlogged soil. 

The colossal worms are very fragile, despite their stature. Their bodies can easily tear if picked up or moved too roughly, causing them to bleed with bright red blood. There are even anecdotes of fields running “red with blood” when the worm’s habitat was first cleared and plowed by farmers. 

Their sex lives are shrouded in mystery. They are hermaphrodites, so every worm has both male and female sexual organs. When two worms breed, they exchange sperm with each other and use it to fertilize their own eggs. However, it’s not clear how this process occurs, as it all takes place underground and has never been witnessed by a human.

In the spring–summer season, they can produce a single translucent amber-coloured egg, about the size of a small, super skinny chicken egg. This egg contains a single young and takes over a year to hatch. Oddly enough, they’ve never been successfully bred in captivity, leaving even more mystery surrounding their reproduction.

Given all of these challenges, the giant Gippsland earthworm is listed as “vulnerable” to extinction under the IUCN Red List. Like many gentle giants of the world, it's a species that's faced with an uncertain future on a rapidly changing planet.