A mule is the offspring of a male donkey and a female horse. Horses and donkeys are different
species, with different numbers of chromosomes. Of the two F1 hybrids between these two species,
a mule is easier to obtain than a hinny, which is the product of a female donkey and a male
horse. The size of a mule and work to which it is
put depends largely on the breeding of the mule's dam. Mules can be lightweight, medium
weight, or even, when produced from draft horse mares, of moderately heavy weight.
It has been claimed that mules are "more patient, sure-footed, hardy and long-lived than horses,
and they are considered less obstinate, faster, and more intelligent than donkeys."
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. One of several terms for a gelded mule is a "John mule."
Biology The median weight range for a mule is between
about 370 and 460 kg. Although it depends on the individual animal, an army mule can
"carry up to 72 kg and walk 26 km without resting." In general, a mule can be packed
with "dead weight" of up to 20% of its body weight, or approximately 90 kg. The average
equine in general can carry up to approximately 30% of its body weight in "live" weight, such
as a rider. While a few mules can carry live weight up to 160 kg, the superiority of the
mule becomes apparent in their additional endurance.
One of the virtues of the mule is the size and ground-covering ability of a horse, but
is comparatively stronger than a horse of similar size and inherits the endurance and
disposition of the donkey father. Mules also tend to be more independent than most other
domesticated equines other than the donkey. Mules also tend to require less food than
a horse of similar size. A male mule is properly called a horse mule,
though often called a john mule. A female mule is properly called a mare mule, though
often called a Molly mule. A young male mule is called a mule colt, and a young female
is called a mule filly. Characteristics
With its short thick head, long ears, thin limbs, small narrow hooves, and 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. 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 a renowned example of hybrid vigor. 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."
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. Mules exhibit a higher cognitive intelligence than their parent species. This
is also believed to be the result of hybrid vigor, similar to how mules acquire greater
height and endurance than either parent. 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. 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. Sometimes, mules whimper.
Color and size variety Mules come in a variety of shapes, sizes and
colors, from minis under 50 lb to maxis over 1,000 lb, 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. Mares homozygous for
the Lp gene bred to any color donkey will produce an Appaloosa colored mule.
Distribution The Food and Agriculture Organization of the
United Nations reports that China was the top market for mules in 2003, closely followed
by Mexico and many Central and South American nations.
Fertility 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. There are no recorded cases of fertile mule
stallions. A few mare mules have produced offspring when mated with a purebred horse
or donkey. Herodotus gives an account of such an event as an ill omen of Xerxes' conquest
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".
As of October 2002, there had been only 60 documented cases of mules birthing foals since
1527. In China in 2001, a mare mule produced a filly. In Morocco in early 2002 and Colorado
in 2007, mare mules produced colts. Blood and hair samples from the Colorado birth verified
that the mother was indeed a mule and the foal was indeed her offspring.
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 the A&M College of Texas in the late
1920s. One of the foals was a female, sired by a jack. Unlike its mother, it 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.
Modern mules
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. However, in the United States, a dedicated number of
mule breeders continued the tradition as a hobby and continued breeding the great lines
of American Mammoth Jacks started in the United States by George Washington with the gift
from the King of Spain of two Catalan donkeys. These hobby breeders began to utilize better
mares for mule production until today's modern saddle mule emerged. Exhibition shows where
mules pulled heavy loads have now been joined with mules competing in Western and English
pleasure riding, as well as dressage and show jumping competition. There is now a cable
TV show dedicated to the training of donkeys and mules. Mules, once snubbed at traditional
horse shows, have been accepted for competition at the most exclusive horse shows in the world
in all disciplines. Mules are still used extensively to transport
cargo in rugged roadless regions, such as the large wilderness areas of California's
Sierra Nevada mountains. 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. As of July 2014, there are at least sixteen commercial
mule pack stations in business in the Sierra Nevada. The Angeles chapter of the Sierra
Club has a Mule Pack Section that organizes hiking trips with supplies carried by mules.
Amish farmers, who reject tractors and most other modern technology for religious reasons,
commonly use teams of six or eight mules to pull plows, disks, 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, 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.
Mule clone In 2003, researchers at University of Idaho
and Utah State University produced the first mule clone as part of Project Idaho. 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. See also
African wild ass Forty acres and a mule
Headless Mule, a cursed woman in Brazilian folklore
Horse Hinny, the reciprocal cross to the mule
Jennet, a small Spanish horse Kiang, the Tibetan ass
Onager, the Asiatic wild ass References
Further reading Buchholz, Katharina. "Colorado miracle mule
foal lived short life, but was well-loved". Denver Post. Retrieved 2014-07-16.
Chandley, A. C.; Clarke, C. A.. "Cum mula peperit". Journal of the Royal Society of
Medicine 78: 800–801. PMC 1289943. PMID 4045882. Loftus, Bill. "It's a Mule: UI produces first
equine clone". Here We Have Idaho: The University of Idaho Magazine: 12–15. Retrieved 2014-07-16.
Lukach, Mark. "There Is a Man Wandering Around California With 3 Mules". The Atlantic. Retrieved
2014-07-16. Rong, R.; Chandley, A. C.; Song, J.; McBeath,
S.; Tan, P. P.; Bai, Q.; Speed, R. M.. "A fertile mule and hinny in China". Cytogenetic
and Genome Research 47: 134. doi:10.1159/000132531. Williams, John O; Speelman, Sanford R. "Mule
production". Farmers' Bulletin 1341. Retrieved 2014-07-16. Hosted by the UNT Digital Library.
Originally published by the U.S. Government Printing Office.
External links American Donkey and Mule Society
American Mule Association British Mule Society
Canadian Donkey & Mule Association Western Mule Magazine