Prehistory In The Flesh 2015 – The Przewalski’s horse
Commentary by Lucy M. Warner
September 22, 2016
https://www.google.com/search?q=Cave+horses&espv=2&biw=1024&bih=659&site=webhp&tbm=isch&imgil=OVNQy9Fsj9U2IM%253A%253BXiQE917rfM959M%253Bhttp%25253A%25252F%25252Fuk.phaidon.com%25252Fagenda%25252Fart%25252Fpicture-galleries%25252F2011%25252Fmarch%25252F10%25252Finside-the-cave-of-forgotten-dreams%
Photographs of over fifteen lovely and impressive cave paintings in France appear at this Google website, which consist mostly of these magnificent horses, but also one Rhinoceros, bison, aurox. and what appears to be an ibex. The artists are thought to be what is now called Aurignacian Man from around 30,000 BP. If this statement makes you think of crude stick figures, think again. The other primitive art I’ve seen (Australian Aboriginal and Native American work) is all or mostly stick figures, but the artists at Lascaux clearly show an attempt to portray reality and the talent to do it. Artistic talent is not an automatic part of human intelligence, but is present in a goodly number of individuals.
I think at Lascaux Cave there was artistic talent on hand, an organized religious element with a shaman, and a prosperous and fairly numerous community. Not only are the cave paintings as naturalistic and beautiful as any modern artist’s work, they look almost exactly like the modern photograph of a Przewalski’s horse in its habitat from the Scientific American article. Among the horse paintings on this Google site are two of a spotted horse with black head and neck which is a good bit like an Appaloosa, and one of the more standard brown and buff colored type, which was rearing up as if to fight, with a sun disc in the sky above. Some of those cave paintings are just plain and incomplete depictions, but this is definitely an attempt to paint the world as it existed for them at the time.
Some have a spear dangling out of the animal’s side, some with a clearly recognizable HEART drawn on their sides, and a few with human body combinations. I think that depicts a shaman doing a magical dance with a horse’s head, probably to placate a horse spirit or god before going out on a hunt. If that sounds “far out,” the idea is from a video filmed by anthropologists of some Australian Aboriginal men hunting. I had two anthropology courses, one of more standard culture based information, and the other with wonderfully interesting things like that video. In that video, when the animal was killed, the hunter did a short ritual with his hands and a chant over its body to placate the life spirit for the taking of a life. Human sensibility goes way, way back, and it is perpetuated from parent to child in stories which we call myth, while the teller of the tale calls them sacred! So let’s not be scornful of Native American views about the recent oil pipeline which has destroyed part of their sacred lands, a burial site I believe. Those old bones are their ancestors. The Native American community has had legal battles with archaeologists over their really thoughtless habit of storing the bones of ancestors in collection drawers rather than allowing the tribes to rebury their dead with a proper ceremony.
From the La Pileta cave in Spain there is a group of horses depicted with crude stick figure drawings of humans with a lead attached as though to ride it or use it for the bearing of burdens, and one stick figure of a horse with what appears to be a man on its back. The horses depicted were clearly accustomed to humans – “tamed” if not “domesticated” in that case. One of the images also shows what looks like a large dog with pointed ears and what may be a strange looking structure or even an altar.
That is found on the net at http://www.vectorstock.com/royalty-free-vector/ancient-cave-drawings-vector-617747. The website http://www.aquilapre.com.au/History.html gives the probable date of horse domestication as 5,000 BC, so it is unclear to me where the images of men holding a rope from the horse’s head come from and at what dates. That would be a question to answer at another time and by scholars. The picture of a dog and men with horses standing peacefully together at www.aquilapre.com shows a farming/herding environment, I would say, or at least the animals are used to the company of humans, if not for doing work, for an easier source of food than a hunting scenario. The earliest connection, however, between men and dogs does, according to other articles I’ve read, possibly go back to the 30,000 date. The first known use of domesticated horses goes back to the presence of chariots in the Middle East and among the Celtic tribes. Dogs are different. A dog or wolf skeleton was found buried in a cave at that 30,000 BC time period. I think some of the cave drawings with haltered horses may be more recent than the Aurignacian art work, though.
The following articles concern dates of earliest horse domestication, though not necessarily including selective breeding. See below.
Recommended – a large number of Internet images found on cave walls at Lascaux and other French and Spanish sites, which are pretty obviously very similar to the extant Przewalski’s Horse, going by the way they look; though not so closely similar in DNA according to the Scientific American article below, Przewalski’s horse is one of the few examples of a “truly wild” horse breed. The elegance of some of the cave artists’ renditions is amazing to me for a “cave man” from 30,000 BP. Go to this Scientific American article below and to the Google item above to examine and compare the recent scientific photograph of the sturdy and beautiful modern day animal to its’ cousins on the cave walls.
http://blogs.scientificamerican.com/thoughtful-animal/10-things-you-didne28099t-know-about-przewalskie28099s-horses/
Scientific American
10 Things You Didn’t Know About Przewalski’s Horses
By Jason G. Goldman | February 3, 2014
Happy Year of the Horse! The New Year began in China on Friday, but celebrations continue for a full week, meaning that I can still wish you a happy new year.
In honor of the Year of the Horse, here are 10 things you didn't know about my favorite kind of horse, Przewalski's horse.
The what horse? The first thing you should know about Przewalski's horse is how to say it. Przewalski is a Polish word, and it belongs to Nikolai Przhevalsky. But we're getting ahead of ourselves. Przewalski is pronounced shuh-VAL-skee. But you can call it a "P-horse" and most conservationists, zoologists, and zoo keepers and curators will know what you're talking about.
Okay, so Przewalski or Przhevalsky? At one time it was thought that the Przewalski horse was first "discovered" by the Russian explorer Colonel Nikolai Przhevalsky, who lived from 1839 to 1888. It turns out that it was actually discovered and described earlier, but the name stuck. For some reason - and I'm not quite certain why - the Polish spelling became associated with the animal, rather than the Russian spelling. It was actually in the 15th century that the P-horse was first sighted by a European. A German writer named Johann Schiltberger recorded a description of the animal in one of his diaries, "A Journal Into Heathen Parts," while traveling through Mongolia as a prisoner of a Mongol Khan named Egedi. Mongolians, presumably, were quite familiar with the Przewalski's horse prior to Schiltberger's visit, but they may have called it the tahki. Other acceptable names are: Asian wild horse, Przewalski's wild horse, and Mongolian wild horse. There was a time when it was called a "tarpan," but pretty much everybody agrees that it's not a tarpan.
What is a P-horse? Everybody might agree that they're not tarpans, but that's about where the agreement ends. It is clear that the Przewalski's horse is a wild, undomesticated horse. In fact, it's the only surviving species of wild horse. Other "wild" horses, like the American mustang, are actually descended from feral domesticated horses who escaped from their herds and adapted to life outside of direct human influence. Much like their equid cousins, the zebras and African wild asses, Przewalski's horses have never been successfully domesticated.
While there are those who would argue that all domestic horses (Equus caballus) are descended from Przewalski's horses (Equus przewalskii), recent genetic evidence suggests otherwise. In 2011, a group of researchers used a powerful sequencing technique to determine that P-horses form their own clade, separate from the lineage that includes domestic horses. "Our results suggest that Przewalski's horses have ancient origins and are not the direct progenitors of domestic horses," they write. "The analysis of the vast amount of sequence data presented here suggests that Przewalski's and domestic horse lineages diverged at least [117,000 years ago]." (Other research puts the divergence more recently, 38–72 thousand years ago). The consensus is that both domestic and Przewalski's horses are derived from a common ancestor, similar to the way in which humans and chimpanzees share a common ancestor, rather than either species being derived from the other.
Modified from: Goto et al., (2011). Genome Biol. Evol. 3:1096–1106.
“[HTML] A massively parallel sequencing approach uncovers ancient origins and high genetic variability of endangered Przewalski's horses
H Goto, OA Ryder, AR Fisher… - Genome biology …, 2011 - gbe.oxfordjournals.org
Abstract The endangered Przewalski's horse is the closest relative of the domestic horse
and is the only true wild horse species surviving today. The question of whether Przewalski's
horse is the direct progenitor of domestic horse has been hotly debated. Studies of DNA ...”
"Viable breeding. Usually, species that have a different number of chromosomes can't breed and create viable offspring. For example, domestic horses have 64 pairs of chromosomes and donkeys have 62. When they breed and give birth to a mule, with 63 chromosome pairs, it is usually sterile. The Przewalski's horse has 66 chromosomes, the most of any equid species. When a P-horse and a domestic horse breed, their offspring are born with 65 chromosomes. Surprisingly, those offspring are usually viable. Still, the P-horse and the domestic horse are usually considered separate species.
The fall of the P-horse. The Przewalski's horse became well known to Western science only in 1881 when Przhevalsky described it. By 1900, a German merchant named Carl Hagenbeck had captured most of them. Hagenbeck was a seller of exotic animals, providing critters for zoos throughout Europe and for P.T. Barnum. His legacy for the zoo world is mixed - he was among the first to advocate for more naturalistic enclosures, for example - but the Przewalski's horse undoubtedly suffered. By the time Hagenbeck died in 1913, most of the world's P-horses lived in captivity. But it isn't all his fault. The P-horse was already suffering from over-hunting before Hagenbeck got his hands on them, and the few remaining wild herds continued to suffer from habitat loss and from a handful of particularly harsh winters in the mid-1900s. One herd, who lived in the Askania Nova region of Ukraine, was slaughtered by German soldiers during their World War II occupation. In 1945, there were just 31 remaining P-horses in the world, in just two zoos, in Munich and in Prague. By the end of the 1950s, only 12 individuals remained.
A conservation success story. All P-horses still alive today are descended from nine of those 31 captive horses in 1945. Since then, the Zoological Society of London has worked together with teams of Mongolian researchers to conserve the species. The captive breeding programs were so successful that in just fifty years the species rebounded to over 1500 individuals by the early 1990s. Some 300 Przewalski's horses have been reintroduced to their native Mongolian habitat. Those herds now graze the fields of the Khustain Nuruu National Park, Takhin Tal Nature Reserve, Khar Us Nuur National Park, and Khomiin Tal Reserve. Chinese researchers, who had their own captive breeding program, reintroduced a group into a reserve near the Gobi desert. The largest herd of reintroduced P-horses is once again found in the Askania Nova reserve in southern Russia. Another group has been introduced to the Hungarian Hortobágy National Park. Oh, and there's a herd that is successfully reproducing on its own within the Chernobyl exclusion zone, an area that has effectively become a wildlife refuge. Less than a decade ago, the IUCN reclassified the species from "extinct in the wild" to "endangered."
International Cooperation
Thanks to the work of the Netherlands-based Foundation for the Preservation and Protection of the Przewalski horse, horses were traded between the different breeding programs to maximize genetic diversity. As a result, despite being founded by just nine individuals, the current population of P-horses is genetically sustainable. The Prague Zoo continues to maintain the studbook for the species, a record of the parentage of every individual Przewalski's horse on the planet.
Continuous Monitoring
The horses that were introduced into Hungary's Hortobágy National Park have been constantly monitored by scientists, who are working to understand their natural behaviors. Studies of Przewalski's horse social structure and behavior conducted there continue to help in husbandry and management efforts worldwide. Researchers have learned that P-horses live in small, permanent family groups, which are comprised of a mature stallion, one to three mature females, and their offspring. The juveniles stay within the family group for two to three years before they go off in search of potential mates. Multiple family groups combine to form herds that move together in search of food.
A surgical first. In 2007, veterinary researchers from the National Zoo successfully conducted the first-ever reverse vasectomy on a Przewalski's horse. It wasn't just a first for the species, but the first time such a procedure had been successfully completed on any endangered species. Minnesota - that's his name - originally had the vasectomy in 1999 while he was at the Minnesota Zoo. It was only later that researchers realized how genetically valuable he was, given his ancestry.
An artificial first. It was only a few months ago that the first Przewalski's horse was born as the result of artificial insemination. The insemination process and subsequent birth (a whopping 340 days later) took place at the Smithsonian Conservation Biology Institute (SCBI) in Front Royal, Virginia. The foal was born to a mare named Anne; the first time mother also grew up at SCBI.
The baby P-horse, born July 27, 2013. Photo via Smithsonian National Zoo.
It isn't as simple as collecting some semen and depositing it into a mare. Reproductive physiologist Budhan Pukazhenthi who worked on the project told National Geographic News that "the team learned how to successfully collect semen from stallions, monitored hormone levels in mares, and studied how estrus cycles of Przewalski's horses compared with those of domestic horses." Even then it took seven years to result in a viable pregnancy.
Goto H., Ryder O.A., Fisher A.R., Schultz B., Kosakovsky Pond S.L., Nekrutenko A. & Makova K.D. (2011). A Massively Parallel Sequencing Approach Uncovers Ancient Origins and High Genetic Variability of Endangered Przewalski's Horses, Genome Biology and Evolution, 3 1096-1106. DOI: 10.1093/gbe/evr067
Lau A.N., Peng L., Goto H., Chemnick L., Ryder O.A. & Makova K.D. (2008). Horse Domestication and Conservation Genetics of Przewalski's Horse Inferred from Sex Chromosomal and Autosomal Sequences, Molecular Biology and Evolution, 26 (1) 199-208. DOI: 10.1093/molbev/msn239
Ryder O.A. & Wedemeyer E.A. (1982). A cooperative breeding programme for the Mongolian wild horse Equus przewalskii in the United States, Biological Conservation, 22 (4) 259-271. DOI: 10.1016/0006-3207(82)90021-0omes
https://en.wikipedia.org/wiki/Domestication_of_the_horse
Domestication of the horse
From Wikipedia, the free encyclopedia
A number of hypotheses exist 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 wild horses and were probably hunted for meat. How and when horses became domesticated is disputed. The clearest evidence of early use of the horse as a means of transport is from chariot burials dated c. 2000 BCE. However, an increasing amount of evidence supports the hypothesis that horses were domesticated in the Eurasian Steppes approximately 4000–3500 BCE.[1][2][3] Recent discoveries in the context of the Botai culture suggest that Botai settlements in the Akmola Province of Kazakhstan are the location of the earliest domestication of the horse.[4]
The date of the domestication of the horse depends to some degree upon the definition of "domestication". Some zoologists define "domestication" as human control over breeding, which can be detected in ancient skeletal samples by changes in the size and variability of ancient horse populations. Other researchers look at broader evidence, including skeletal and dental evidence of working activity; weapons, art, and spiritual artifacts; and lifestyle patterns of human cultures. There is also evidence that horses were kept as meat animals prior to being trained as working animals.
Attempts to date domestication by genetic study or analysis of physical remains rests on the assumption that there was a separation of the genotypes of domesticated and wild populations. Such a separation appears to have taken place, but dates based on such methods can only produce an estimate of the latest possible date for domestication without excluding the possibility of an unknown period of earlier gene-flow between wild and domestic populations (which will occur naturally as long as the domesticated population is kept within the habitat of the wild population). Further, all modern horse populations retain the ability to revert to a feral state, and all feral horses are of domestic types; that is, they descend from ancestors that escaped from captivity.
Whether one adopts the narrower zoological definition of domestication or the broader cultural definition that rests on an array of zoological and archaeological evidence affects the time frame chosen for domestication of the horse. The date of 4000 BCE is based on evidence that includes the appearance of dental pathologies associated with bitting, changes in butchering practices, changes in human economies and settlement patterns, the depiction of horses as symbols of power in artifacts, and the appearance of horse bones in human graves.[5] On the other hand, measurable changes in size and increases in variability associated with domestication occurred later, about 2500–2000 BCE, as seen in horse remains found at the site of Csepel-Haros in Hungary, a settlement of the Bell Beaker culture.[6]
Regardless of the specific date of domestication, use of horses spread rapidly across Eurasia for transportation, agricultural work and warfare. Horses and mules in agriculture used a breastplate type harness or a yoke more suitable for oxen, which was not as efficient at utilizing the full strength of the animals as the later-invented padded horse collar that arose several millennia later in western Europe.[7][8]
Predecessors to the domestic horse
A 2005 study analyzed the mitochondrial DNA (mtDNA) of a worldwide range of equids, from 53,000 year old fossils to contemporary horses.[9] Their analysis placed all equids into a single clade, or group with a single common ancestor, consisting of three genetically divergent species: Hippidion, the New World stilt-legged horse, and the true horse. The true horse, which ranged from western Europe to eastern Beringia, included prehistoric horses and the Przewalski's Horse, as well as what is now the modern domestic horse, belonged to a single Holarctic species.
Therefore, the domestic horse today is classified as Equus ferus caballus. No genetic originals of native wild horses currently exist, other than the never-domesticated Przewalski's Horse. The Przewalski has 66 chromosomes, however, as opposed to 64 among modern domesticated horses, and their Mitochondrial DNA (mtDNA) forms a distinct cluster.[12] Genetic evidence suggests that modern Przewalski's horses are descended from a distinct regional gene pool in the eastern part of the Eurasian steppes, not from the same genetic group that gave rise to modern domesticated horses.[12] Nevertheless, evidence such as the cave paintings of Lascaux suggests that the ancient wild horses that some researchers now label the "Tarpan subtype" probably resembled Przewalski horses in their general appearance: big heads, dun coloration, thick necks, stiff upright manes, and relatively short, stout legs.[13]
Equus caballus germanicus front leg, teeth and upper jaw at the Museum für Naturkunde, Berlin
The horses of the Ice Age were hunted for meat in Europe and across the Eurasian steppes and in North America by early modern humans. Numerous kill sites exist and many cave paintings in Europe indicate what they looked like.[14] Many of these Ice Age subspecies died out during the rapid climate changes associated with the end of the last Ice Age or were hunted out by humans, particularly in North America, where the horse became completely extinct.[15]
Classification based on body types and conformation, absent the availability of DNA for research, once suggested that there were roughly four basic wild prototypes, thought to have developed with adaptations to their environment prior to domestication. There were competing theories; some argued that the four prototypes were separate species or subspecies, while others suggested that the prototypes were physically different manifestations of the same species.[13] However, more recent study indicates that there was only one wild species and all different body types were entirely a result of selective breeding or landrace adaptation after domestication. Either way, the most common theories of prototypes from which all modern breeds are thought to have developed suggests than in addition to the so-called Tarpan subtype, there were the following base prototypes:[13]
The "Warmblood subspecies" or "Forest Horse" (once proposed as Equus ferus silvaticus, also known as the Diluvial Horse), which evolved into a later variety sometimes called Equus ferus germanicus. This prototype may have contributed to the development of the warmblood horses of northern Europe, as well as older "heavy horses" such as the Ardennais.
The "Draft" subspecies, a small, sturdy, heavyset animal with a heavy hair coat, arising in northern Europe, adapted to cold, damp climates, somewhat resembling today's draft horse and even the Shetland pony.
The "Oriental" subspecies (once proposed as Equus agilis), a taller, slim, refined and agile animal arising in Western Asia, adapted to hot, dry climates. It is thought to be the progenitor of the modern Arabian horse and Akhal-Teke.[13]
Only two never-domesticated "wild" groups survived into historic times, Przewalski's horse (Equus ferus przewalski), and the Tarpan (Equus ferus ferus).[16] The Tarpan became extinct in the late 19th century and Przewalski's horse is endangered; it became extinct in the wild during the 1960s, but was re-introduced in the late 1980s to two preserves in Mongolia. Although researchers such as Marija Gimbutas theorized that the horses of the Chalcolithic period were Przewalski's, more recent genetic studies indicate that Przewalski's horse is not an ancestor to modern domesticated horses.[12] Other subspecies of Equus ferus appear to have existed and could have been the stock from which domesticated horses are descended.[16]
Genetic evidence[edit]
See also: Genomics of domestication and History of horse domestication theories
A 2014 study compared DNA from ancient horse bones that predated domestication and compared them to DNA of modern horses, discovering 125 genes that correlated to domestication. Some were physical, affecting muscle and limb development, cardiac strength and balance. Others were linked to cognitive function and most likely were critical to the taming of the horse, including social behavior, learning capabilities, fear response, and agreeableness.[17] The DNA used in this study came from horse bones 16,000 to 43,000 years ago, and therefore the precise changes that occurred at the time of domestication have yet to be sequenced.[18]
The domestication of stallions and mares can be analyzed separately by looking at those portions of the DNA that are passed on exclusively along the maternal (mitochondrial DNA or mtDNA) or paternal line (Y-chromosome or Y-DNA). DNA studies indicate that there may have been multiple domestication events for mares, as the number of female lines required to account for the genetic diversity of the modern horse suggests a minimum of 77 different ancestral mares, divided into 17 distinct lineages.[12] On the other hand, genetic evidence with regard to the domestication of stallions points at a single domestication event for a limited number of stallions combined with repeated restocking of wild females into the domesticated herds.[19][20][21]
A study published in 2012 that performed genomic sampling on 300 work horses from local areas as well as a review of previous studies of archaeology, mitochondrial DNA, and Y-DNA suggested that horses were originally domesticated in the western part of the Eurasian steppe.[22] Both domesticated stallions and mares spread out from this area, and then additional wild mares were added from local herds; wild mares were easier to handle than wild stallions. Most other parts of the world were ruled out as sites for horse domestication, either due to climate unsuitable for an indigenous wild horse population or no evidence of domestication.[23]
Genes located on the Y-chromosome are inherited only from sire to its male offspring and these lines show a very reduced degree of genetic variation (aka genetic homogeneity) in modern domestic horses, far less than expected based on the overall genetic variation in the remaining genetic material.[19][20] This indicates that a relatively few stallions were domesticated, and that it is unlikely that many male offspring originating from unions between wild stallions and domestic mares were included in early domesticated breeding stock.[19][20]
Genes located in the mitochondrial DNA are passed on along the maternal line from the mother to her offspring. Multiple analyses of the mitochondrial DNA obtained from modern horses as well as from horse bones and tooth from archaeological and palaeological finds consistency shows an increased genetic diversity in the mitochondrial DNA compared to the remaining DNA, showing that a large number of mares has been included into the breeding stock of the originally domesticated horse.[12][21][24][25][26][27] Variation in the mitochondrial DNA is used to determine so-called haplogroups. A haplogroup is a group of closely related haplotypes that share the same common ancestor. In horses, seven main haplogroups are recognized (A-G), each with several subgroups. Several haplogroups are unequally distributed around the world, indicating the addition of local wild mares to the domesticated stock.[12][21][25][26][27] One of these haplotypes (Lusitano group C) is exclusively found on in Iberian Peninsula, leading to a hypothesis that the Iberian peninsula or North Africa was an independent origin for domestication of the horse.[25] However, until there is additional analysis of nuclear DNA and a better understanding of the genetic structure of the earliest domestic herds, this theory cannot be confirmed or refuted.[25] It remains possible that a second, independent, domestication site might exist but, as of 2012, research has neither confirmed nor disproven that hypothesis.[23]
Even though horse domestication became widespread in a short period of time, it is still possible that domestication began with a single culture, which passed on techniques and breeding stock. It is possible that the two "wild" subspecies remained when all other groups of once-"wild" horses died out because all others had been, perhaps, more suitable for taming by humans and the selective breeding that gave rise to the modern domestic horse.[28]
Archaeological evidence[edit]
The Hyksos, c. 1600 BCE
Evidence for the domestication of the horse comes from three kinds of sources: 1) changes in the skeletons and teeth of ancient horses; 2) changes in the geographic distribution of ancient horses, particularly the introduction of horses into regions where no wild horses had existed; and 3) archaeological sites containing artifacts, images, or evidence of changes in human behavior connected with horses.
Archaeological evidence includes horse remains interred in human graves; changes in the ages and sexes of the horses killed by humans; the appearance of horse corrals; equipment such as bits or other types of horse tack; horses interred with equipment intended for use by horses, such as chariots; and depictions of horses used for riding, driving, draught work, or symbols of human power.
Few of these categories, taken alone, provide irrefutable evidence of domestication, but combined add up to a persuasive argument. Horses interred with chariots[edit]
The least ancient, but most persuasive evidence of domestication comes from sites where horse leg bones and skulls, probably originally attached to hides, were interred with the remains of chariots in at least 16 graves of the Sintashta and Petrovka cultures. These were located in the steppes southeast of the Ural Mountains, between the upper Ural and upper Tobol Rivers, a region today divided between southern Russia and northern Kazakhstan. Petrovka was a little later than and probably grew out of Sintashta, and the two complexes together spanned about 2100–1700 BCE.[5][29] A few of these graves contained the remains of as many as eight sacrificed horses placed in, above, and beside the grave.
In all of the dated chariot graves, the heads and hooves of a pair of horses were placed in a grave that once contained a chariot. Evidence of chariots in these graves was inferred from the impressions of two spoked wheels set in grave floors 1.2–1.6m apart; in most cases the rest of the vehicle left no trace. In addition a pair of disk-shaped antler "cheekpieces," an ancient predecessor to a modern bit shank or bit ring, were placed in pairs beside each horse head-and-hoof sacrifice. The inner faces of the disks had protruding prongs or studs that would have pressed against the horse's lips when the reins were pulled on the opposite side. Studded cheekpieces were a new and fairly severe kind of control device that appeared simultaneously with chariots.
All of the dated chariot graves contained wheel impressions, horse bones, weapons (arrow and javelin points, axes, daggers, or stone mace-heads), human skeletal remains, and cheekpieces. Because they were buried in teams of two with chariots and studded cheekpieces, the evidence is extremely persuasive that these steppe horses of 2100–1700 BCE were domesticated. Shortly after the period of these burials, the expansion of the domestic horse throughout Europe was little short of explosive. In the space of possibly 500 years, there is evidence of horse-drawn chariots in Greece, Egypt, and Mesopotamia. By another 500 years, the horse-drawn chariot had spread to China.
Dung and corrals[edit]
Soil scientists working with Sandra Olsen of the Carnegie Museum of Natural History at the Chalcolithic (also called Eneolithic, or "Copper Age") settlements of Botai and Krasnyi Yar in northern Kazakhstan found layers of horse dung, discarded in unused house pits in both settlements.[38] The collection and disposal of horse dung suggests that horses were confined in corrals or stables. An actual corral, dated to 3500–3000 BCE was identified at Krasnyi Yar by a pattern of post holes for a circular fence, with the soils inside the fence yielding ten times more phosphorus than the soils outside. The phosphorus could represent the remains of manure.[39]
Geographic expansion[edit]
The appearance of horse remains in human settlements in regions where they had not previously been present is another indicator of domestication. Although images of horses appear as early as the Upper Paleolithic period in places such as the caves of Lascaux, France, suggesting that wild horses lived in regions outside of the Eurasian steppes prior to domestication and may have even been hunted by early humans, concentration of remains suggests animals being deliberately captured and contained, an indicator of domestication, at least for food, if not necessarily use as a working animal.
Around 3500–3000 BCE, horse bones began to appear more frequently in archaeological sites beyond their center of distribution in the Eurasian steppes and were seen in central Europe, the middle and lower Danube valley, and the North Caucasus and Transcaucasia. Evidence of horses in these areas had been rare before, and as numbers increased, larger animals also began to appear in horse remains. This expansion in range was contemporary with the Botai culture, where there are indications that horses were corralled and ridden. This does not necessarily mean that horses were first domesticated in the steppes, but the horse-hunters of the steppes certainly pursued wild horses more than in any other region. This geographic expansion is interpreted by many zoologists as an early phase in the spread of domesticated horses.[30][40][41]
European wild horses were hunted for up to 10% of the animal bones in a handful of Mesolithic and Neolithic settlements scattered across Spain, France, and the marshlands of northern Germany, but in many other parts of Europe, including Greece, the Balkans, the British Isles, and much of central Europe, horse bones do not occur or occur very rarely in Mesolithic, Neolithic or Chalcolithic sites. In contrast, wild horse bones regularly exceeded 40% of the identified animal bones in Mesolithic and Neolithic camps in the Eurasian steppes, west of the Ural Mountains.[40][42][43]
Horse bones were rare or absent in Neolithic and Chalcolithic kitchen garbage in western Turkey, Mesopotamia, most of Iran, South and Central Asia, and much of Europe.[40][41][44] While horse bones have been identified in Neolithic sites in central Turkey, all equids together totaled less than 3% of the animal bones. Within this three percent, horses were less than 10%, with 90% or more of the equids represented by onagers (Equus hemionus) or another ass-like equid that later became extinct, Equus hydruntinus.[45] Onagers were the most common native wild equids of the Near East. They were hunted in Syria, Anatolia, Mesopotamia, Iran, and Central Asia; and domesticated asses (Equus asinus) were imported into Mesopotamia, probably from Egypt, but wild horses apparently did not live there.[46]
http://www.nytimes.com/2011/11/08/science/spotted-horses-in-cave-art-werent-just-a-figment-dna-shows.html?_r=0
Spotted Horses in Cave Art Weren’t Just a Figment, DNA Shows
By HILLARY ROSNER
NOV. 7, 2011
Photograph -- SEEING SPOTS Drawings of horses from the Chauvet cave in France, right, and a horse from the Lascaux cave, also in France. Credit French Ministry of Culture and Communication
Roughly 25,000 years ago in what is now southwestern France, human beings walked deep into a cave and left their enduring marks. Using materials like sticks, charcoal and iron oxides, they painted images of animals on the cave walls and ceilings — lions and mammoths and spotted horses, walking and grazing and congregating in herds.
Today, the art at the Pech-Merle cave, and in hundreds of others across Europe, is a striking testimony to human creativity well before modern times.
But what were these cave paintings, exactly? Were prehistoric artists simply sketching what they saw each day on the landscape? Or were the images more symbolic, diverging from reality or representing rare or even mystical creatures? Such questions have divided archaeologists for years.
Now, a group of researchers has used distinctly modern techniques to help decipher the mystery, at least in the case of Pech-Merle’s famous spotted horses. By comparing the DNA of modern horses and those that lived during the Stone Age, scientists have determined that these drawings are a realistic depiction of an animal that coexisted with the artists.
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A modern horse with leopard spots like those seen in France's Pech-Merle cave. Comparing DNA from the present and the Stone Age convinced scientists that those spotted depictions were based on existing animals. Credit Thomas Hackmann
The research, published online on Monday in the journal Proceedings of the National Academy of Sciences, grew out of an effort to discern the coat colors of ancient horses to help figure out when the animals were domesticated, a pivotal moment in the development of human societies. In general, domesticated species exist in a far greater variety of colors than wild ones, so understanding color variation in fossil animals can help pinpoint the timing.
Previous research on DNA from the bones and teeth of horses that lived 7,000 to 20,000 years ago showed that those animals were either black or bay (a brown coat with a black mane and tail). That work was published in the journal Science in 2009. Since then, geneticists have deciphered the underlying code for the spotted pattern, known as leopard, in modern horses. So the scientists went back to their samples, looking for the leopard sequence in horses that lived in Europe 11,000 to 15,000 years ago.
“There is a striking correspondence between the coat-color patterns of horses painted in Paleolithic caves of France with what geneticists found in the genotypes” — the specific genetic sequences — “of color genes,” said Hopi E. Hoekstra, an evolutionary biologist at Harvard who studies pigmentation. Dr. Hoekstra was not involved in the study but called it “very convincing.”
An author of the study, Michael Hofreiter, an evolutionary biologist at the University of York in England, said: “Why they took the effort making these beautiful paintings will always remain a miracle to us.
“It’s an enigma, but it’s also nice to see that if we go back 25,000 years, people didn’t have much technology and life was probably hard, but nevertheless they already endeavored in producing art. It tells us a lot about ourselves as a species.”
Extracting DNA from such old material is a complex process, and the potential for contamination is huge. Early studies of Neanderthal DNA were marred by contamination from humans, and led to skepticism about the field’s future.
Since then, researchers have adopted strict procedures to ensure they are not contaminating ancient samples with modern-day DNA. The procedures include analyzing ancient and contemporary material in physically separate facilities and replicating results multiple times.
“This is a whole different level of clean,” said Jessica L. Metcalf, a postdoctoral researcher at the University of Colorado who also works with the Australian Center for Ancient DNA in Adelaide, where the labs that work on ancient and modern DNA are more than half a mile apart.
“We have sealed rooms with HEPA filter air flow, UV lights that sterilize when you come in,” she said. “We spend over half our time cleaning. We use a lot of bleach. You’re in this ridiculous-looking clean suit with a face shield on.”
In fact, Dr. Hofreiter said, researchers who work with ancient horse genes should not even go horseback riding. “Traces of DNA,” she said, “they just stick to people.”
Dr. Hofreiter, 38, began his career working with a pioneer of ancient DNA research, Svante Paabo. Though he intended to study taxonomy, he was so intrigued by the idea of extracting DNA from ancient material that he switched his focus. “You have this 30,000-year-old piece of feces in your hand,” he said, adding: “Well, you should wear gloves. And you can actually get to the genetic code from the animal. And I thought, this is so fascinating.”
He and his colleagues did not set out to study cave art. They were simply continuing their work on coat color in prehistoric horses. Only after they found the spotted horse gene in their ancient samples did they realize they could say something about archaeology.
“What we found is that there were really only these three color patterns — spotted or dappled; blackish ones; and brown ones,” he said. “These are the three phenotypes we find in the wild populations. And then we realized these phenotypes are exactly the ones you see in cave paintings.”
Terry O’Connor, an archaeologist at the University of York who collaborated on the study, said spotted horses in particular had been used to argue that cave art was more symbolic than realistic, and that as a result the finding could cause a stir. But now it is clear that some horses had a gene for that coat color. “People drew spotty horses,” he said, “because they saw spotty horses.”
Last summer, exploring a cave in the Dordogne region, Dr. O’Connor said he became transfixed by a series of line drawings of mammoths. “They were absolutely superb, some using contours of the cave itself, capturing the size and shape and movement,” he said. “You look at that and say, ‘These guys know what the animals looked like, and they can draw.’ ”
As techniques for working with ancient DNA have matured, scientists are now using it to answer an increasing variety of questions about the past — from what happened to a species’ genetic variation as its environment changed to how humans recolonized Europe after the last ice age to what type of microbes lived in the guts of people and animals thousands of years ago.
“One of the things that most pleases me about this paper as a piece of ancient DNA science,” Dr. O’Connor said, “is it kind of begins with a question. These spotty horses, were they magical or real?
“And then science answers that. It’s not just, ‘Let’s rip the DNA out of ancient bones and see what it tells us.’ ”
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