Palouse Environmental Update: Field Identification of the Giant Palouse Earthworm (Driloleirus americanus)

By David Hall, Vice President, Paradise Ridge Defense Coalition

The Giant Palouse Earthworm is native to the Palouse region and is one of the few native worms in all of America. The size of its geographic range is unknown. The Giant Palouse Earthworm has been found primarily on the Palouse of Idaho and Washington, but a few have been identified in central Washington.

Since 2012, Cass Davis, an avid fisher, hunter, and all-around outdoors enthusiast who has lived on Paradise Ridge for the past 20 years, has discovered about a dozen specimens of this extremely rare earthworm in Latah County. He finds them on the ground during or following rains.

If you find a suspected Giant Palouse Earthworm, take identification photographs (including close-ups of each end), note where you found it (GPS coordinates are great), and put it out of danger of being run over or stepped upon. Then report your findings to representatives of the Palouse Prairie Foundation or the University of Idaho Soils Department.

The Giant Palouse Earthworm is the only known worm species native to the Palouse Prairie. It was first described in 1897.

Key features of Driloleirus americanus

  •       No pigmentation
  •       Clitellum is located at segments 13-18
  •       Tail is bulbous


Baugher, Chris. October 17, 2013. "Stalking the Giant Palouse Earthworm." Presentation to the Palouse Prairie Foundation.

Palouse Prairie Foundation