Review: Did The Yamnaya Ride Horses?

Trautmann et al. 2023. First bioanthropological evidence for Yamnaya horsemanship

The domestication and use of horses as mounts profoundly changed human history. It should really rank alongside agriculture, dairying, blue-water sailing and other major breakthroughs for creating an entirely novel human niche - the ability to live and move through the steppe, much like camels in the desert. Generally the dates between 3,500 and 3,000 BC are seen as the period when horses became widely domesticated and their milk used for food, somewhere between Hungary and the Kazakh steppe. What has remained elusive though is pinning down when and where people began riding horses. Questionable evidence from apparent bits or altered horse molars has never fully convinced researchers, but in a new paper based on the bioarchaeology of people, rather than horses, I think we have our strongest evidence to date.

A combined team from Finland, Romania, Hungary, Bulgaria and the US (including David Anthony, author of The Horse, the Wheel, and Language: How Bronze-Age Riders from the Eurasian Steppes Shaped the Modern World) looked at 217 skeletons of ‘steppe riders’ dated to between the 5th and 2nd millennia BC, some of which were identified with the Yamnaya or Corded Ware cultures. Of these 45 had died under 16 years of age. Of the remaining, some 14%, or 23 individuals, showed evidence in their bones of prolonged horse riding. Five in particular, all Yamnaya, were singled out as likely examples of the earliest horseback riders.

Taking a step back, what does it mean to have skeletal evidence for riding horses?

This research was not the first to look at archaeological evidence for riding. In fact two main areas have independently developed diagnostic criteria for understanding how riding impacts the human skeleton. The first were North American anthropologists interested in the emergence of the Native American Plains Cultures, and the second is from Hungary and her neighbours, interested in the origins of people like the Huns, Avars and other Eurasian steppe nomads. The skeletal markers they identified are clustered together in something called ‘horse riding syndrome’ or ‘horsemanship syndrome’.

From the paper: Horse riding and the shape of the acetabulum: Insights from the bioarchaeological analysis of early Hungarian mounted archers (10th century)

From the main paper -supplementary materials

The effects of riding of the human body include:

• Entheseal stress reactions on pelvis and femur

• Acetabular ovalization

• Femoroacetabular alteration

• Change to bone-shaft cross-sectional shape

• Stress-induced vertebral degeneration

• Trauma by accident

What we’re mostly looking at here are identifiable changes to the bones around the pelvis, in particular the acetabulum, which is the cup-shaped socket structure of the pelvis which connects to the head of the femur. Stress to this joint can cause a number of things, the most prominent in the literature being acetabular ovalization. In layman’s terms this is when the circular socket of the hip begins to elongate vertically, becoming more oval-shaped. This is a key indicator of long-term horse riding stress, so much so that many research papers rely solely or predominantly on this skeletal marker:

The so-called horse riding syndrome refers to a combination of changes on the human skeleton, which may indicate that the individual in question practised horse riding as a habitual activity during his or her lifetime. The aim of this paper is to identify potential differences in habitual horse riding activity between different socioeconomic groups within the adult male population of the Avar cemetery of Wien 11-Csokorgasse, using a major criterion of the horse riding syndrome (namely the ovalization or vertical elongation of the acetabulum) and an indicator of social status in burials of Avar men (namely the depth of burial). The sample included only males (age group adult or older) with at least one completely preserved acetabulum (n = 38 for the left acetabulum, n = 40 for the right acetabulum). The ovalization of the acetabulum was determined using a basic measurement method, the Index of Ovalization of Acetabulum (IOA)

- Bühler & Kirchengast, 2022

No single criteria however can definitively prove that someone regularly rode horses during their life, any interpretation has to weigh all the available bioarchaeological evidence and available contextual evidence, such as grave goods, time period, historical writing, material culture and so on. Bone preservation is also a huge factor, and even with all of this in mind, the osteology will not always be definitive:

Finally, through direct measurements and the calculation of an index, one probable Merovingian horse rider revealed very elongated acetabula compared with a reference collection (Baillif‐Ducros et al., 2012), whereas, with the same method, Sarry, Courtaud, and Cabezuelo (2016) did not observe particularly elongated acetabula in a La Tène period mass burial associating eight horses and eight human individuals. However, bone preservation was a limiting factor.

- Berthon et al, 2018

To create the best possible interpretation, the researchers for this Yamnaya paper created a probability score system, whereby different bone markers were given a value and a cut-off point was used to determine the likelihood that an individual was a rider during their lives.

As you can see, the ovalization scoring was not all that high, and ultimately the researchers picked out only 9 individuals who could qualify. Five of these were identified as Yamnaya, spanning three countries and about 400 years (approx 3000 - 2600 BC). The other four included two older and two younger burials. One of these though is quite important.

This burial from Csongrád-Kettőshalom in Hungary is of a young man (25-35 years old), who displays a high number of horsemanship syndrome traits. But, the date range for his burial is 4442–4243 cal BC, which is much earlier than anticipated. It is not impossible that he was one of the first riders, given the presence of horse-head maces, images and horse bones in graves between 4800-4000 BC (Suvorovo, Khvalynsk and Samara cultures), but this seems more speculative than the paper was aiming for. It could also be the case though that other activities produced these skeletal markers, and the authors themselves list barrel-making and basket-weaving.

Interestingly all the samples which passed the probability threshold were male, which suggests that, if they were riders, it may have been an elite male activity only. Fully nomadic steppe or plains societies saw both women and men mounted on horses, but these came after a prolonged period of domestication. The earliest horses would have been much more difficult to ride and certainly less reliable in conflict than later breeds. From the paper:

This supports other tentative third millennium BCE evidence of an early onset of equines as mounts (44). However, because of the lack of specialized gear and a comparably short breeding and training history, early horses were probably hard to handle. As Librado et al. (1) demonstrate, Yamnaya horses were markedly closer to the equid lineage known as DOM2, including all modern domestic horses, than were wild steppe horses from the sixth millennium BCE. When DOM2 was bred from late Yamnaya horses in the steppes during the second half of the third millennium BCE, genes for reduced anxiety/fear response were selected and retained in all later DOM2 horse breeds. Even DOM2 horses can be highly strung and excitable animals, so a still greater anxiety response in early Yamnaya horses probably made them even more likely to “bolt” from violent or loud actions. The military benefit of equestrianism may therefore have been limited; but nevertheless, rapid transport to and away from the site of raids would have been an advantage, even if combat was carried out on foot. Riding certainly was useful for patrolling wide tracts of land and controlling larger herds of livestock (45). It consequently would have contributed substantially to the overall success of pastoral Yamnaya society.

We have to avoid the temptation of conflating the later Mongol or Plains Indians with these earliest pastoralists, if they were riding then it was with less ease and efficiency. It is possible that this added to the prestige of riding itself, a semi-wild animal which could injure and maim the rider is a challenge of mastery and courage. Any man who could successfully ride one and even use it to scare and attack his enemies would presumably receive great acclaim.

Overall, the team managed to whittle down 217 skeletons to just 9 identifiable riders, assuming we agree with their conclusions. This points to riding being an infrequent activity across early steppe populations, which makes sense. The Hungarian outlier suggests that riding started even earlier than the Yamnaya, or some other occupation has to account for his skeleton, which of course lessens the impact of this paper. I think given the context, location and time period, it makes sense that a small number of men began riding horses, but there are still nagging doubts here and hopefully further studies with control samples can help clear these up.