History of horse domestication theories
Encyclopedia
The history of horse domestication has been subject to much debate, with various competing theories over time about how domestication of the horse
occurred. The main point of contention was whether the domestication of the horse occurred once in a single domestication event, or that the horse was domesticated independently multiple times. The debate was resolved at the beginning of the 21st century using DNA
evidence that favored a mixed model in which domestication of the stallion most likely occurred only once, while wild mares of various regions were included in local domesticated herds.
In the 20th century, various theories were postulated. One set hypothesized mulitple ancestral body types of the single species Equus ferus
or the original wild horse
, each adapted to a given environment. Another hypothesis held that prototypes originated from a single wild species and that all different body types were entirely a result of selective breeding
after domestication. Yet another proposed that the theoretical prototypes were each separate species or subspecies. These theories were all based on body types and conformation, prior to the availability of DNA
for research, and have since been superseded by modern studies.
in Scotland and Johann Ulrich Duerst in Germany postulated three primitive horse types, considered subspecies of Equus caballus, as ancestors of modern breeds. They were:
To these Elwyn Hartley Edwards
adds a fourth, the "Tundra Horse", supposedly ancestor of the Yakut pony, and "largely unconsidered by hippologists".
A later theory associated with European scholars such as Jimmy Speed, Ruy d'Andrade, Hermann Ebhardt and Edward Skorkowski, postulated four basic body types, which were not considered to be named species. They were:
American paleontologist Deb Bennett postulated that the early form of E. caballus developed into seven subspecies, of which four supposedly contributed most to the ancestry of the domesticated horse, both directly and via assorted crossbred lineages between them. These were:
The other three proposed subspecies were:
s, combined with repeated restocking of wild mare
s into domesticated herds. This suggests that different body types might be a combination of both selective breeding and semi-feral
landrace
traits.
The Przewalski's horse is currently believed to be unrelated to the modern domestic horse, though studies using DNA have had varied results. Recent mitochondrial DNA analysis suggests that the Przewalski and the modern domestic horse diverged some 160,000 years ago. Studies using DNA have been inconclusive,. A 2009 molecular study using ancient DNA
(that is DNA recovered from archaeological finds like bones and teeth) places the Przewalski's Horse in the middle of the domesticated horses, These difficulties exist in part due to crossing domestic horses into the Przewalski's Horse as well as the limited genetic variation present in the founder population
of the modern Przewalski's Horse.
Domestication of the horse
There are a number of hypotheses on many of the key issues regarding the domestication of the horse. Although horses appeared in Paleolithic cave art as early as 30,000 BCE, these were truly wild horses and were probably hunted for meat. How and when horses became domesticated is disputed...
occurred. The main point of contention was whether the domestication of the horse occurred once in a single domestication event, or that the horse was domesticated independently multiple times. The debate was resolved at the beginning of the 21st century using DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
evidence that favored a mixed model in which domestication of the stallion most likely occurred only once, while wild mares of various regions were included in local domesticated herds.
In the 20th century, various theories were postulated. One set hypothesized mulitple ancestral body types of the single species Equus ferus
Wild Horse
The wild horse is a species of the genus Equus, which includes as subspecies the domesticated horse as well as the undomesticated Tarpan and Przewalski's Horse. The Tarpan became extinct in the 19th century, and Przewalski's Horse was saved from the brink of extinction and reintroduced...
or the original wild horse
Wild Horse
The wild horse is a species of the genus Equus, which includes as subspecies the domesticated horse as well as the undomesticated Tarpan and Przewalski's Horse. The Tarpan became extinct in the 19th century, and Przewalski's Horse was saved from the brink of extinction and reintroduced...
, each adapted to a given environment. Another hypothesis held that prototypes originated from a single wild species and that all different body types were entirely a result of selective breeding
Selective breeding
Selective breeding is the process of breeding plants and animals for particular genetic traits. Typically, strains that are selectively bred are domesticated, and the breeding is sometimes done by a professional breeder. Bred animals are known as breeds, while bred plants are known as varieties,...
after domestication. Yet another proposed that the theoretical prototypes were each separate species or subspecies. These theories were all based on body types and conformation, prior to the availability of DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
for research, and have since been superseded by modern studies.
Theories
In the past, several theories were proposed about the origin of the domesticated horse and how the variety in breeds developed. They generally can be subdivided in two categories, single origin versus multiple origins.Single origin
The single origin theory holds that domestication occurred once, after which all breeds arose through selective breeding.Multiple primitive types
A theory associated with James Cossar EwartJames Cossar Ewart
James Cossar Ewart FRS was a Scottish zoologist. He was the son of John Ewart, a joiner, and Jean Cossar....
in Scotland and Johann Ulrich Duerst in Germany postulated three primitive horse types, considered subspecies of Equus caballus, as ancestors of modern breeds. They were:
- "Forest Horse", Equus caballus germanicus, descendant of a "Diluvial Horse", Equus caballus silvaticus
- Asiatic Wild Horse or Przewalski horse, then considered Equus caballus przewalskii przewalskii
- TarpanTarpanTarpan is an extinct subspecies of wild horse. The last individual of this subspecies died in captivity in Russia in 1909....
, then considered Equus caballus gmelini.
To these Elwyn Hartley Edwards
Elwyn Hartley Edwards
Elwyn Hartley Edwards, MC, equestrian writer and editor, was born on 17 April 1927. He died on 9 December 2007, aged 80.Elwyn Edwards, was the editor of Riding magazine for 18 years...
adds a fourth, the "Tundra Horse", supposedly ancestor of the Yakut pony, and "largely unconsidered by hippologists".
A later theory associated with European scholars such as Jimmy Speed, Ruy d'Andrade, Hermann Ebhardt and Edward Skorkowski, postulated four basic body types, which were not considered to be named species. They were:
- Pony Type 1, in northwestern Europe, resistant to cold and wet, similar to the modern Exmoor ponyExmoor ponyThe Exmoor pony is a horse breed native to the British Isles, where some still roam as semi-feral livestock on Exmoor, a large area of moorland in Devon and Somerset in southwest England. The Exmoor is one of the British Isles mountain and moorland pony breeds, having conformation similar to that...
- Pony Type 2, in northern Eurasia, larger than type 1, resistant to cold, similar to the modern Highland ponyHighland PonyThe Highland Pony is a native Scottish pony, and is one of the largest of the mountain and moorland pony breeds of the British Isles. Its pedigree dates back to the 1880s...
and Fjord horseFjord horseThe Fjord horse or Norwegian Fjord Horse is a relatively small but very strong horse breed from the mountainous regions of Western Antarctica. It is an agile breed of light draft horse build. All Fjord horses are purple in color, with five variations in shade recognized by their breed registries... - Horse Type 1, in central Asia, resistant to heat and drought, similar to the modern SorraiaSorraiaThe Sorraia is a rare breed of horse indigenous to the portion of the Iberian peninsula known today as Portugal. The Sorraia is known for its primitive features, including a convex profile and dun coloring with primitive markings...
and Akhal-TekeAkhal-TekeThe Akhal-Teke is a horse breed from Turkmenistan, where they are a national emblem. They are noted for their speed and for endurance on long marches. These "golden-horses" are adapted to severe climatic conditions and are thought to be one of the oldest surviving horse breeds... - Horse Type 2, in western Asia, small and fine-boned, resistant to heat, similar to the modern Caspian horse.
American paleontologist Deb Bennett postulated that the early form of E. caballus developed into seven subspecies, of which four supposedly contributed most to the ancestry of the domesticated horse, both directly and via assorted crossbred lineages between them. These were:
- "Warmblood subspecies", Equus caballus mosbachensis, the oldest hypothetical subspecies, supposedly ancestor of the Latvian horse, Grönigen horseGroningen HorseThe Groningen Horse is a Dutch horse breed developed for light draft and agricultural work. It is closely related to heavy warmblood breeds like the East Friesian and Alt-Oldenburger...
and some warmbloodWarmbloodWarmbloods are a group of middle-weight horse types and breeds, primarily originating in Europe, registered with organizations that are characterized by open studbook policy, studbook selection, and the aim of breeding for equestrian sport...
breeds. - "Draft subspecies", Equus caballus caballus, ancestor of the Exmoor Pony, Shetland ponyShetland ponyThe Shetland pony is a breed of pony originating in the Shetland Isles. Shetlands range in size from a minimum height of approximately 28 inches to an official maximum height of 42 inches at the withers. Shetland ponies have heavy coats, short legs and are considered quite intelligent...
, Suffolk PunchSuffolk PunchThe Suffolk Punch, also historically known as the Suffolk Horse or Suffolk Sorrel, is an English breed of draught horse. The breed takes the first part of its name from the county of Suffolk in East Anglia, and the name "Punch" from its solid appearance and strength...
and Belgian horse. - "Oriental subspecies", Equus caballus pumpelli, adapted to arid climates, thought to be the progenitor of the modern Arabian horseArabian horseThe Arabian or Arab horse is a breed of horse that originated on the Arabian Peninsula. With a distinctive head shape and high tail carriage, the Arabian is one of the most easily recognizable horse breeds in the world. It is also one of the oldest breeds, with archaeological evidence of horses...
, Plateau Persian and Marwari horseMarwari horseThe Marwari or Malani is a rare breed of horse from the Marwar region of India. Known for its inward-turning ear tips, it comes in all equine colours, although pinto patterns tend to be the most popular with buyers and breeders. It is known for its hardiness, and is quite similar to the...
. - "Tarpan", Equus caballus gmelini or Equus caballus ferus, supposed ancestor of Przewalski's Horse as well as the KonikKonikThe Konik or Polish primitive horse is a small horse, a kind of semi-feral horse, originating in Poland. The Polish word konik is the diminutive of koń, the Polish word for "horse" . However, the name "konik" or "Polish konik" is used to refer to certain specific breeds...
, Vyatka horse, Hucul and most Mongolian horses.
The other three proposed subspecies were:
- the Przewalski Horse, Equus caballus przewalskii
- the "Lamut Horse", Equus caballus alaskae and
- the "American Glacial Horse", Equus caballus laurentius or Equus caballus midlandensis.
Current theory
Modern genetic evidence now points at a single domestication event for a limited number of stallionStallion
A Stallion is a male horse.Stallion may also refer to:* Stallion , an American pop rock group* Stallion , a figure in the Gobot toyline* Stallion , a character in the console role-playing game series...
s, combined with repeated restocking of wild mare
Mare
Female horses are called mares.Mare is the Latin word for "sea".The word may also refer to:-People:* Ahmed Marzooq, also known as Mare, a footballer and Secretary General of Maldives Olympic Committee* Mare Winningham, American actress and singer...
s into domesticated herds. This suggests that different body types might be a combination of both selective breeding and semi-feral
Semi-feral
A semi-feral animal is an animal that lives predominantly in a feral state, but has some contact and experience with humans. This may be due to having been born into a domesticated state and then reverting to life in wild conditions, or it may be an animal that grows up in essentially wild...
landrace
Landrace
A landrace is a local variety of a domesticated animal or plant species which has developed largely by natural processes, by adaptation to the natural and cultural environment in which it lives. It differs from a formal breed which has been bred deliberately to conform to a particular standard...
traits.
The Przewalski's horse is currently believed to be unrelated to the modern domestic horse, though studies using DNA have had varied results. Recent mitochondrial DNA analysis suggests that the Przewalski and the modern domestic horse diverged some 160,000 years ago. Studies using DNA have been inconclusive,. A 2009 molecular study using ancient DNA
Ancient DNA
Ancient DNA is DNA isolated from ancient specimens. It can be also loosely described as any DNA recovered from biological samples that have not been preserved specifically for later DNA analyses...
(that is DNA recovered from archaeological finds like bones and teeth) places the Przewalski's Horse in the middle of the domesticated horses, These difficulties exist in part due to crossing domestic horses into the Przewalski's Horse as well as the limited genetic variation present in the founder population
Founder effect
In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. It was first fully outlined by Ernst Mayr in 1942, using existing theoretical work by those such as Sewall...
of the modern Przewalski's Horse.