Donkeys and mules
Donkeys and mules are domesticated members of the horse family, known scientifically as Equidae. Donkeys, believed to be descendants of the African wild ass, have been utilized as pack animals and for agricultural work for approximately six thousand years. They are well-suited to arid environments, having been bred to maximize work output while minimizing feed requirements. Mules, which result from crossing a male donkey and a female horse, exhibit unique characteristics such as a donkey-like head and long ears, combined with the body of a horse. Known for their strength, durability, and surefootedness, mules are recognized for their capacity to carry heavier loads than either parent species, showcasing the concept of hybrid vigor. Historically, both donkeys and mules have played vital roles in transportation and agriculture, particularly before the advent of modern machinery. Although their populations have declined in the wild due to human activities, domestic donkeys and mules continue to thrive alongside humans, serving various functions in communities around the world.
Donkeys and mules
Donkey and Mule Facts
Classification:
- Kingdom: Animalia
- Subkingdom: Bilateria
- Phylum: Chordata
- Subphylum: Vertebrata
- Class: Mammalia
- Subclass: Theria
- Order: Perissodactyla
- Family: Equidae (horses)
- Genus and species:Equus asinus (donkeys or domestic asses);E. asinus bred withEquus caballus (mules)
- Geographical location: The domestic donkey is descended from the wild ass of the hot deserts of Africa and Arabia; both the donkey and the mule were introduced to wide areas of Europe, Asia, Africa, and later to both North and South America
- Habitat: Donkeys and mules are well-adapted to hot, dry deserts, yet selective breeding has produced donkeys that thrive in the damp climate of Ireland
- Gestational period: 11.5 months
- Life span: Twenty to twenty-five years on average
- Special anatomy: Long ears dissipate heat; broad single toe (hoof) on each foot is an adaptation for running; capable of digesting large quantities of low-protein fodder
The donkey and mule are members of the horse family (Equidae). Like other equids, they are fast runners adapted for life on open grasslands and deserts. Their posture is unguligrade, meaning that they run on the tips of their toes. Their legs are long and adapted for speed. Each foot has only one toe—the hoof—another adaptation for speed. Equids are grazers and sometimes browsers. Asses especially will browse.
The Donkey
The donkey or domestic ass is descended from the African wild ass. Donkeys first appeared on wall paintings and in burials six thousand years ago in Egypt and western Asia. They have been used widely by farmers and traders as pack animals and to pull wheeled vehicles.
Donkeys have been bred to be smaller than their ancestor, the African wild ass. The goal was to produce a thrifty animal that gave the greatest amount of work for the least amount of feed. Being descended from a desert animal, donkeys are better suited to the Mediterranean climate than to northern Europe. Donkeys were introduced to China in the third century BCE. Donkeys were brought to the Americas by the Spanish, who call them “burros,” beginning in the seventeenth century.
It is possible, but awkward, to ride a donkey. Because of the animal’s low withers, a human rider must sit far back in the donkey seat to avoid sliding forward. This produces a bumpy ride and has precluded the donkey’s use as a mount in hunting or battle.
The Mule
The mule is the offspring of a male donkey (jackass) and a female horse (mare). The opposite cross—a female donkey (jenny) bred to a male horse (stallion)—produces a hinny. A mule has a donkey’s large head and long ears, the body of a horse, and an asslike tail. Its voice is a bray that is somewhat different than that of the ass. Some mules are quite large: as much as sixteen hands (sixty-four inches) at the withers.
Mules are strong and durable. They are more surefooted and can bear heavier loads than either the horse or the donkey. This is a good example of hybrid vigor or heterosis: the tendency of hybrids to be larger and more durable than their parent species. It is often said that a mule is smarter than a horse because a horse may overeat and “loun der” (become ill from overeating) if given unlimited access to grain, but a mule will not. Mules are almost always infertile, apparently due to differing numbers of chromosomes in the gametes of the horse and the donkey.
Donkeys and Mules in History
Donkeys have been used in agriculture and transport for at least six thousand years. Mules were essential in transport for at least three thousand years, from ancient times until the invention of the steam engine and the building of railroads. Mules can be ridden but were used mostly in mule teams or mule trains to pull wheeled vehicles in both peace and war. For example, the twenty-mule teams of Death Valley, California, hauled two wagons loaded with borax plus a water wagon with a combined weight of over twenty-seven tons.
Wild populations of equids have been greatly reduced by humans through hunting and habitat destruction, some to the point of extinction, such as the tarpan. Przewalski's horse (Equus ferus; also known as the Asian or Mongolion wild horse) was once classified as extinct. However, in 1996, one wild individual was found. Reintroductions have increased the wild population to around fifty individuals, according to the IUCN Red List of Threatened Species. However, the subspecies is still listed as endangered. The Domestic horses, donkeys, and mules, however, have thrived for thousands of years in association with humankind. Despite being largely replaced by mechanical power, domestic equids are still common.
Principal Terms
browsers: eaters of bushes, scrub vegetation, and bark
equids: members of the horse family (Equidae) including horses, asses (including the donkey), zebras, and their crosses (including the mule and the hinny)
grazers: eaters of grasses
hybrid: an organism resulting from the crossing of two species
hybrid vigor or heterosis: the tendency of hybrids to be larger and more durable than their parent species
unguligrade: walking on the tips of the toes
Bibliography
Attar, Cynthia. The Mule Companion: A Guide to Understanding the Mule. 4th ed. Partner Communications, 1998.
Clutton-Brock, Juliet. Horse Power: A History of the Horse and the Donkey in Human Societies. Harvard UP, 1992.
Clutton-Brock, Juliet. A Natural History of Domesticated Mammals. 2nd ed. Cambridge UP, 1999.
Hodges, Meredith. Training Mules and Donkeys: A Logical Approach to Longears. Alpine, 1993.
Hutchins, Betsy. Definitive Donkey. American Donkey and Mule Society, 1999.
Campbell Smith, Donna. The Book of Donkeys: A Guide to Selecting, Caring, and Training. Lyons Press, 2016.