Overview: When Frank Smith first unearthed this giant earthworm near Pullman in 1897, he named it Megascolides americanus, thinking that it was closely related to Australia's fifteen-foot worms (Megascolides australis). Although dwarfed by its Australian counterpart, the three-foot long Palouse is certainly a giant among worms. This species, really only distantly related to Megascolides, was renamed Driloleirus which means "lily-like worm," reflecting the peculiar flowery aroma that it emits when handled. Since its initial discovery, very few other sightings of this species have been documented. The giant Palouse earthworms live in the deep, rich soils of the Palouse bunchgrass prairies. Thick layers of organic matter that have accumulated in the soils of the Palouse for hundreds of years sustain the giants during the wetter seasons. During summer droughts, the worms dig burrows as deep as fifteen feet, conserving water with specialized kidney-like organs, called nephridia. Farmers that arrived in eastern Washington prized the fertile Palouse soils, resulting in the almost complete destruction of the bunchgrass prairies that characterized this region by the late 1800's. Today, the Palouse prairies are considered to be the rarest ecosystem in Washington. The biggest threat to these elusive giants continues to be habitat destruction due to agriculture and development, but the introduction of the now widespread European earthworm has also helped to further the decline of our native Palouse worm. A documented sighting of this rare creature has not been recorded since 1978, when one was unearthed in the Palouse country of Washington State.
Distribution: The Palouse is an area of rolling dune-like hills and rich farmland in eastern Washington and northern Idaho.