According to recent research published in the journal Science, Native Americans used horses in the American West much earlier than previously believed. A University of Wyoming (UW) graduate's own research has made significant contributions to the research. UW is where Cassidee Thornhill obtained both her undergraduate and graduate degrees in anthropology. Thornhill discussed her research with Kamila Kudelska of Wyoming Public Radio.

Kamila Kudelska: What was the legend around Native Americans and horses?

Cassidee Thornhill: We already knew that the introduction of horses into Indigenous cultures had a significant impact on daily living, travel distances, and conflict. Numerous aspects of Native American lifeways were altered. We were aware that many Plains tribes, in particular, really came to identify strongly as a horse country. However, the majority of what we do know about how the relationship got started comes from historical writings and recordings, which is obviously somewhat biased. Only from the perspective of European Americans.

KK: What kind of study did you conduct?

CT: When I first got interested in it, I spoke with Danny Walker, a zoo archaeologist. He served as the state's assistant archaeologist. He was also able to direct me to the Blacks Fork River horse in particular because he had performed the original analysis on that animal. The only other horse from this era that is currently known to be without a certain not Euro-American is only a skull fragment, and it is located just outside of Casper. And just being aware that there were only two in all of Wyoming throughout this time period suggests further research is necessary, in my opinion.

KK: How did you approach that, then?

CT: Due to its completeness, I determined that the Blacks Fork River horse was a really good example that could use re-analysis and additional analysis of the remains. As I have stated, the skull in Casper is really a fragment—just the skull's base. That really doesn't give us very much to work with. And across the Plains, a great number of horses are like this.

I wanted to re-establish the horse's age, which is about in line with what they had discovered in the initial examination and is between five and six months. Because fortunately some other department members were conducting research on differentiating between stone and metal cut marks, I made the decision to take a closer look at the human modifications, the cut and chop marks. I therefore wanted to particularly apply that research to this.

The most crucial step, in my opinion, was resubmitting some radiocarbon dates because the first ones they provided were too broad and didn't really provide us a clear picture of when this horse had passed away. The other date then simply came back as "modern," which is also not very helpful for determining when the horse had passed away. To try to recreate it using more modern techniques, in my opinion, is the most crucial item that can be added.

KK: What did your findings indicate?

CT: On the spine, on the ribs, and on the femurs, there were numerous cut and chop marks, primarily chalk marks. The cut and chop marks on these horses, however, are completely different from the ones we typically see on other animals and horses in other areas of the world that are being eaten for food. Aside from the possibility that it was simply ritually buried, it appears that this horse was partially disarticulated before being placed. There is little to no evidence of any kind of de-fleshing, skinning, or anything else that would suggest that it was being used in any way. Three coyote skulls had also been buried with it.

Because no other artifacts were discovered with it, it is crucial that I was able to determine that all of the cut and chop marks were made by metal tools. The horses are also much earlier than we would ordinarily expect, and there are no artifacts made of chipped stone or even of metal. For Wyoming at the period, the use of metal tools is also very recent.

The medium date, which is 1640, was returned, which is a little early. Based on rock art, which is notoriously difficult to date, as well as what we could learn from historical documents and oral histories, it was first believed that horses arrived in Wyoming around 1600. However, 1640 places the timeline a little bit earlier, which is important because in the original account of how horses spread throughout the Plains, it was believed that horses couldn't have escaped from the Spanish before 1680, which is when the Pueblo Revolt took place in New Mexico. However, 1640 is not absurdly early, but it does place the timeline a little bit earlier.

The initial hypothesis was that after the revolution, the Pueblo people were able to acquire these horses and subsequently spread them out more widely across the Plains. However, the 1640 date indicates that they were likely transmitted through non-European transmission by Indigenous peoples earlier than we had previously assumed, giving Indigenous peoples more agency.

KK: The study that was recently published in Science adds to the body of evidence supporting what you just said. Can you now elaborate on how the additional research influenced what you discovered?

CT: With the help of new Science research, various aspects of the morphology of the skull could be discussed in more detail. The horse's skull was injured when I conducted the analysis, but Will Taylor, the lead author of the Science publication, was able to examine it more closely and saw that it had almost healed, which may have been the result of veterinary care. The horse was therefore hurt in some way—likely by being booted by another horse—and at least temporarily taken care of.

The study includes a number of different horses. The article includes a lot of talk on another horse that is from Kansas. Furthermore, it shares a similar age with the Black Forks horse. It displays proof that a metal bit was used. I believe both the Kansas horse and the Black Forks horse underwent isotopic study. They observed indications that the Kansas horse may have received grain or maize in addition to whatever else was in its diet, most likely during the winter.

They were able to determine that the isotope levels for the Black Forks horse corresponded with other isotope levels for that particular region of Wyoming, indicating that the horse was likely born and raised there exclusively until it was five or six months old and that its mother had likely been there for a short while. These two horses, along with some of the other data mentioned in that article, demonstrate that the spread of horses is not an accident. The Blacks Fork horse is the digital evidence that, indeed, horses did spread from the Southwest before the Pueblo Revolt, most likely through the networks of trade that Indigenous people had established.

KK: Why does that matter?

CT: I suppose it's noteworthy because the original story doesn't really emphasize how quickly horses spread among Indigenous people or how they assimilated them. A common early myth is that they couldn't have obtained horses before the Pueblo Revolt, however this is probably untrue.

According to certain sources, some parties were likely raiding Spanish and Pueblo populations in the southwest. They may have taken and transported horses with them to the north, where they were disseminated through trade networks. The fact that many of the narratives up to this point have been heavily biased in favor of Euro-American records, in my opinion, is what is most important. This only serves to demonstrate how much more nuanced the tale is than we first believed.

The Blacks Fork horse, in particular, provides proof of the Comanche people; their ancestors were Shoshone speakers and came from that region of Wyoming. They were once believed to have relocated to the south in order to get horses. The Blacks Fork horse, however, suggests that this is most likely untrue; it suggests that they had horses before they moved south and that they used their equine expertise and exceptional horsemanship to colonize a sizable portion of the southern plains and eventually build an empire based on horses and bison.