Prior to its rediscovery in 2010, the worm was believed to give off a scent similar to that of the lily flower when handled[2] and that it was able to spit in self-defense;[3] however, the specimens captured did not exhibit these capabilities.Such nature of burrowing for Giant Palouse Earthworm was recorded to a depth of as much as 15 feet, and it is said to aestivate during dry seasons.

The fertile soil consists of deep loess hills enriched with volcanic ash and rich layers of organic matter.

A summer 2009 project was launched by Jodi Johnson-Maynard, a University of Idaho associate professor and a soil ecologist specializing in macroinvertebrates, to find specimens.

As of 2001[update], the World Conservation Union (IUCN) has considered the giant Palouse earthworm vulnerable due to loss of habitat and competition from non-native species.

This determination prompted a number of environmental organizations to sue the agency for violation of the ESA and Administrative Procedures Act in order "to ensure the vanishing giant earthworm receives the protection it deserves.

"[11] However, on February 12, 2009, the U.S. District Court for the Eastern District of Washington upheld the decision of the USFWS, finding the FWS's determination "that an organization's request for listing the giant Palouse earthworm (Driloleirus americanus) (GPE) as a threatened or endangered species under the Endangered Species Act was not supported by substantial information was a reasonable determination where the organization had to rely almost entirely upon circumstantial evidence.

At each point along the analytical path, whether considering the extent of the GPE's habitat, its population, or potential threats to its existence, the FWS provided a rational basis for declining to draw the inferences sought by the organization.