A Mule Skinner was person who operated a tool called a fresno. The fresno was attached to a mule and they would operate like CAT scrappers. These machines have a "trailer" that can drop into the ground and skin a .10-8 inchs of soil. That my friends is where the term skinner comes from. If you use a cat bulldozer you are consider a cat skinner, a scraper operator is a pull skinner. Mule skinning was a very physical task in that you had to drop the fresno into the soil and use the mule fill it, then walk behind to a fill area and dump. Repeat the process 20-60 times daily. Rough work!!