“Silent Pards” by L. Ron Hubbard
Publication date: November 1938
Original publication: Western Story Magazine
Story description: Four human rattlesnakes jump Old Cherokee’s rich gold claims, leaving him for dead. But they overlook his two silent partners—Hardtack his dog and Joe, his mule.
Currently available as part of the Stories from the Golden Age series, in the title The Toughest Ranger.