Ecologists have stumbled across some rather special worms on the remote Isle of Rum , just off the coast of Scotland.

These common earthworms (Lumbricus terrestris) are three times the size of the worms found on the mainland, measuring up to 40 centimeters (1.3 feet) long and weighing a whopping 12.5 grams (0.4 ounces).

Experts from the Earthworm Research Group from the University of Central Lancashire have been studying worms on the island since 1995 and believe they managed to reach this size from their undisturbed and isolated location.

They were found in Papadil, an abandoned settlement on the island. The Isle of Rum is home to only around 30 people and there are also very few natural predators, such as moles, badgers, hedgehogs and foxes, which would normally hunt out the worms. Unlike most animals, earthworms can continue to grow even after they reach maturity, so without the threat of becoming a mole’s dinner, they can grow to these huge sizes.

Ecologists at Papadil, Isle of Rum, Scotland. Image credit: Dr Kevin Butt.

Speaking to IFLScience, Dr Kevin Butt, who led the research, said: “Normally they are predated by birds, mammals, reptiles, amphibians, other invertebrates – and may only live for a couple of years at most.

“However, some of the larger species may be able to persist for more than this, for example I’ve kept Lumbricus terrestris in the lab for five years. When given optimum conditions of food, soil, temperature, light, population density, they can grow very large.”

Papadil is also endowed with rich and fertile soils with a crumbly structure – perfect for these wiggling beasts to thrive. But in turn, the worms also help the soil ecology of this area of the island.

Dr Butt explained to The Telegraph , “Without their activities we’d be a lot worse off. They’re just as important as bees are in pollinating plants. They help aerate the soil and drain away water and stop surface erosion.”