Maine has a rich and diverse population of earthworms in its soil, none of them native species. Emeritus Dana Professor of Geology Donaldson Koons reported that the late Gordon Gates '19, a Colby biology professor in the mid-20th century and a world authority on earthworms, concluded that all such worms in Maine were introduced. As with many species of crayfish, bait fish and even salamanders, some of Maine's earthworms got established after fishermen discarded unused bait. Dirt coming in with imported plants brought additional intruders.

Gates's worm work may have been groundbreaking, so to speak, but (perhaps not surprisingly) it took a half century for this story to find its way into the mainstream press. On Labor Day National Public Radio's news show All Things Considered carried a story on invasive earthworms in northern forests. The report, emanating from Wisconsin, said the escaped and introduced creatures were chewing up the previously undisturbed forest floor, creating problems for maples and other trees as well as for forest fauna. One group adversely affected, the story said, were salamanders, which need a thick, undigested duff layer to thrive.