Mule

"Mule and Ass" by Hendrik Goltzius or Hieronymus Wierix, 1578

The mule is valued because, while it has the size and ground-covering ability of its dam, it is stronger than a horse of similar size and inherits the endurance and disposition of the donkey sire, tending to require less food than a horse of similar size. Mules also tend to be more independent than most domesticated equines other than its parental species, the donkey.

The median weight range for a mule is between about 370 and 460 kg (820 and 1,000 lb).[5] While a few mules can carry live weight up to 160 kg (353 lb), the superiority of the mule becomes apparent in their additional endurance.[6]

In general, a mule can be packed with dead weight of up to 20% of its body weight, or approximately 90 kg (198 lb).[6] Although it depends on the individual animal, it has been reported that mules trained by the Army of Pakistan can carry up to 72 kilograms (159 lb) and walk 26 kilometres (16.2 mi) without resting.[7] The average equine in general can carry up to approximately 30% of its body weight in live weight, such as a rider.[8]

A female mule that has estrus cycles and thus, in theory, could carry a fetus, is called a "molly" or "Molly mule", though the term is sometimes used to refer to female mules in general. Pregnancy is rare, but can occasionally occur naturally as well as through embryo transfer. A male mule is properly called a horse mule, though often called a john mule, which is the correct term for a gelded mule. A young male mule is called a mule colt, and a young female is called a mule filly.[9]

Ancient Greek rhyton in the shape of a mule's head, made by Brygos, early 5th century BC. Jérôme Carcopino Museum, Department of Archaeology, Aleria

With its short thick head, long ears, thin limbs, small narrow hooves, and a short mane, the mule shares characteristics of a donkey. In height and body, shape of neck and rump, uniformity of coat, and teeth, it appears horse-like.[10] The mule comes in all sizes, shapes and conformations. There are mules that resemble huge draft horses, sturdy quarter horses, fine-boned racing horses, shaggy ponies and more.

The mule is an example of hybrid vigor.[11] Charles Darwin wrote: "The mule always appears to me a most surprising animal. That a hybrid should possess more reason, memory, obstinacy, social affection, powers of muscular endurance, and length of life, than either of its parents, seems to indicate that art has here outdone nature."[12]

The mule inherits from its sire the traits of intelligence, sure-footedness, toughness, endurance, disposition, and natural cautiousness. From its dam it inherits speed, conformation, and agility.[13]^:5–6,8 Mules are reputed to exhibit a higher cognitive intelligence than their parent species. That said, there is a lack of robust scientific evidence to back up these claims. There is preliminary data from at least two evidence based studies, but they rely on a limited set of specialized cognitive tests and a small number of subjects.[14][15] Mules are generally taller at the shoulder than donkeys and have better endurance than horses, although a lower top speed.[16][14]

Handlers of working animals generally find mules preferable to horses: mules show more patience under the pressure of heavy weights, and their skin is harder and less sensitive than that of horses, rendering them more capable of resisting sun and rain.[10] Their hooves are harder than horses', and they show a natural resistance to disease and insects. Many North American farmers with clay soil found mules superior as plow animals.

A mule does not sound exactly like a donkey or a horse. Instead, a mule makes a sound that is similar to a donkey's but also has the whinnying characteristics of a horse (often starts with a whinny, ends in a hee-haw). Mules sometimes whimper.

Color and size variety

Mules come in a variety of colors and sizes; these mules had a draft horse mare for a mother

A mule battery in the Second Anglo-Afghan War (1879–1880). Sepoys are sitting by the larger field guns.

Mules come in a variety of shapes, sizes and colors, from minis under 200 lb (91 kg) to over 1,000 lb (454 kg), and in many different colors. The coats of mules come in the same varieties as those of horses. Common colors are sorrel, bay, black, and grey. Less common are white, roans, palomino, dun, and buckskin. Least common are paint mules or tobianos. Mules from Appaloosa mares produce wildly colored mules, much like their Appaloosa horse relatives, but with even wilder skewed colors. The Appaloosa color is produced by a complex of genes known as the Leopard complex (Lp). Mares homozygous for the Lp gene bred to any color donkey will produce a spotted mule.

Mules and hinnies have 63 chromosomes, a mixture of the horse's 64 and the donkey's 62. The different structure and number usually prevents the chromosomes from pairing up properly and creating successful embryos, rendering most mules infertile.

A few mare mules have produced offspring when mated with a purebred horse or donkey.[18][19] Herodotus gives an account of such an event as an ill omen of Xerxes' invasion of Greece in 480 BC: "There happened also a portent of another kind while he was still at Sardis—a mule brought forth young and gave birth to a mule" (Herodotus The Histories 7:57), and a mule's giving birth was a frequently recorded portent in antiquity, although scientific writers also doubted whether the thing was really possible (see e.g. Aristotle, Historia animalium, 6.24; Varro, De re rustica, 2.1.28).

As of October 2002, there had been only 60 documented cases of mules birthing foals since 1527.[19] In China in 2001, a mare mule produced a filly.[20] In Morocco in early 2002 and Colorado in 2007, mare mules produced colts.[19][21][22] Blood and hair samples from the Colorado birth verified that the mother was indeed a mule and the foal was indeed her offspring.[22]

A 1939 article in the Journal of Heredity describes two offspring of a fertile mare mule named "Old Bec", which was owned at the time by Texas A&M University in the late 1920s. One of the foals was a female, sired by a jack. Unlike her mother, she was sterile. The other, sired by a five-gaited Saddlebred stallion, exhibited no characteristics of any donkey. That horse, a stallion, was bred to several mares, which gave birth to live foals that showed no characteristics of the donkey.[23]

The mule is "the most common and oldest known manmade hybrid."[24][25] It was likely invented in ancient times in what is now Turkey. They were common in Egypt by 3000 BCE.[24] Homer noted their arrival in Asia Minor in the Iliad in 800 BCE. Mules are mentioned in the Bible (Samuel 2:18:9, Kings 1:18:5, Zacharia 14:15, Psalms 32:9). Christopher Columbus brought mules to the new world.[25] George Washington is known as the Father of the American Mule due to his success in producing 57 mules at his home at Mount Vernon. At the time, mules were not common in the United States, but Washington understood their value as they were "more docile than donkeys and cheap to maintain."[26]

A spotted mule

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 steam then gasoline powered tractors and trucks.

Mules are still used extensively to transport cargo in rugged roadless regions, such as the large wilderness areas of California's Sierra Nevada mountains or the Pasayten Wilderness of northern Washington state. Commercial pack mules are used recreationally, such as to supply mountaineering base camps, and also to supply trail building and maintenance crews, and backcountry footbridge building crews.[27] As of July 2014, there are at least sixteen commercial mule pack stations in business in the Sierra Nevada.[28] The Angeles chapter of the Sierra Club has a Mule Pack Section that organizes hiking trips with supplies carried by mules.[29]

During the Soviet–Afghan War, mules were used to carry weapons and supplies over Afghanistan's rugged terrain to the mujahideen.[30]

Approximately 3.5 million donkeys and mules are slaughtered each year for meat worldwide.[31]

Mule trains have been part of working portions of transportation links as recently as 2005 by the World Food Programme.[32]

A British mule train during the Second Anglo-Boer War, South Africa

Loading mules during exploration of the American West, from Frances Fuller Victor's 1887 book Eleven Years in the Rocky Mountains and a Life on the Frontier.

A mule train is a connected or unconnected line of pack mules, usually carrying cargo. Because of the mule's ability to carry at least as much as a horse, their trait of being sure-footed along with their tolerance of poorer coarser foods and abilities to tolerate arid terrains, mule trains were common caravan organized means of animal powered bulk transport back into pre-classical times. In many climate and circumstantial instances, an equivalent string of pack horses would have to carry more fodder and sacks of high energy grains such as oats, so could carry less cargo. In modern times, strings of sure footed mules have been used to carry riders in dangerous but scenic back country terrain such as excursions into canyons.

Pack trains were instrumental in opening up the American West as the sure footed animals could carry up to 250 pounds (110 kg), survive on rough forage,[lower-alpha 1] did not require feed, and could operate in the arid higher elevations of the Rockies, serving as the main cargo means to the west from Missouri during the heyday of the North American fur trade. Their use antedated the move west into the Rockies as colonial Americans sent out the first fur trappers and explorers past the Appalachians who were then followed west by high-risk-taking settlers by the 1750s (such as Daniel Boone) who led an increasing flood of emigrants that began pushing west over into southern New York, and through the gaps of the Allegheny into the Ohio Country (the lands of western Province of Virginia and the Province of Pennsylvania), into Tennessee and Kentucky before and especially after the American Revolution.

In the nineteenth century, twenty-mule teams, for instance, were teams of eighteen mules and two horses attached to large wagons that ferried borax out of Death Valley from 1883 to 1889. The wagons were among the largest ever pulled by draft animals, designed to carry 10 short tons (9 metric tons) of borax ore at a time.[33]

• 
  World War II British Army pack Mule Train in Italy
• 
  Working mule train, Nicaragua 1957–1961
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  1911 mule train in British Columbia
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  Grand Canyon on the South Kaibab trail
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  1868 mule train fording the Fraser River
• 
  The "Devil's Bridge" at Schöllenen Gorge, St. Gotthard Pass, Switzerland about 1800 (drawing by Peter Birmann)
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  SS Mexican unloading US Army mules in Naples, Italy in Sept. of 1944.
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  Mule cars in Celaya, Guanajuato, Mexico. 1930's

In 2003, researchers at University of Idaho and Utah State University produced the first mule clone as part of Project Idaho.[34] The research team included Gordon Woods, professor of animal and veterinary science at the University of Idaho; Kenneth L. White, Utah State University professor of animal science; and Dirk Vanderwall, University of Idaho assistant professor of animal and veterinary science. The baby mule, Idaho Gem, was born May 4. It was the first clone of a hybrid animal. Veterinary examinations of the foal and its surrogate mother showed them to be in good health soon after birth. The foal's DNA comes from a fetal cell culture first established in 1998 at the University of Idaho.

• Arnold, Watson C. "The Mule: The Worker that 'Can't Get No Respect'," Southwestern Historical Quarterly (2008) 112#1 pp. 34–50. online
• Buchholz, Katharina (2013-08-16). "Colorado miracle mule foal lived short life, but was well-loved". Denver Post. Retrieved 2014-07-16.
• Ellenberg, George B. Mule South to Tractor South: Mules, Machines, and the Transformation of the Cotton South (University of Alabama Press. 2007) 219pp * Chandley, A. C.; Clarke, C. A. (1985). "Cum mula peperit". Journal of the Royal Society of Medicine. 78 (10): 800–801. doi:10.1177/014107688507801003. PMC 1289943. PMID 4045882.
• Loftus, Bill (August 2003). "It's a Mule: UI produces first equine clone". Here We Have Idaho: The University of Idaho Magazine. University of Idaho: 12–15. Retrieved 2014-07-16.
• Lukach, Mark (2013-09-11). "There Is a Man Wandering Around California With 3 Mules". The Atlantic. Atlantic Monthly Group. Retrieved 2014-07-16.
• Rong, R.; Chandley, A. C.; Song, J.; McBeath, S.; Tan, P. P.; Bai, Q.; Speed, R. M. (1988). "A fertile mule and hinny in China". Cytogenetic and Genome Research. 47 (3): 134–9. doi:10.1159/000132531. PMID 3378453.
• Williams, John O; Speelman, Sanford R (1948). "Mule production". Farmers' Bulletin. U.S. Department of Agriculture. 1341. Retrieved 2014-07-16. Hosted by the UNT Digital Library. Originally published by the U.S. Government Printing Office.

Wikimedia Commons has media related to: Mule (category)

Look up mule in Wiktionary, the free dictionary.

• Mule at the Encyclopædia Britannica
• American Donkey and Mule Society
• American Mule Association
• British Mule Society
• Canadian Donkey & Mule Association