Mules

A mule is the offspring of a male donkey (jack) and a female horse (mare). Horses and donkeys are different species, with different numbers of chromosomes. Of the two F1 hybrids (first generation hybrids) between these two species, a mule is easier to obtain than a hinny, which is the offspring of a female donkey (jenny) and a male horse (stallion).

The size of a mule and work to which it is put depend largely on the breeding of the mule's female parent (dam). Mules can be lightweight, medium weight, or when produced from draft horse mares, of moderately heavy weight. Mules are reputed to be more patient, hardy and long-lived than horses, and are described as less obstinate and more intelligent than donkeys.

In the second half of the 20th century, widespread usage of mules declined in industrialized countries. The use of mules for farming and transportation of agricultural products largely gave way to modern tractors and trucks.

In the US, Amish farmers, who reject tractors and most other modern technology for religious reasons, commonly use teams of six or eight mules to pull plows, disk harrows, and other farm equipment, though they use horses for pulling buggies on the road.

During the Soviet war in Afghanistan, the United States used large numbers of mules to carry weapons and supplies over Afghanistan's rugged terrain to the mujahideen. Use of mules by U.S. forces has continued during the War in Afghanistan (2001–2014), and the United States Marine Corps has conducted an 11-day Animal Packers Course since the 1960s at its Mountain Warfare Training Center located in the Sierra Nevada near Bridgeport, California.