Article
A mid-sized hooved mammal with a short head and mane and long ears that is the offspring of two different species -- the donkey and the horse. Most mules are sterile and therefore these animals are not classified as their own species. For the most part, these animals are used for labor, namely, carrying, pulling, and transporting goods in pre-industiral and early-industrial settings.
"A male mule named Beryl," photograph by Unknown. Department of Earth and Planetary Sciences Collection, 1919-2000 (130 002 001 041). Center for Southwest Research, University of New Mexico.
Manuscripts
References
Ellenberg, George B.
2007 Mule South to Tractor South: Mules, Machines, and the Transformation of the Cotton South. Tuscaloosa: University of Alabama Press.