Tuesday, July 9, 2013

Shadows on the Trail - Prehistoric Horses and Native Americans

Books by John Bradford Branney

Prehistoric Horses at a Prehistoric Man Site.        

         In Post Number One of the Shadows on the Trail blog I discussed how I found a man-made Ice Age tool made from Alibates chert from Texas on a northern Colorado ranch. This Ice Age tool was the inspiration for my prehistoric adventure called Shadows on the Trail. 

        Over the past twenty-five years I have found man-made prehistoric artifacts at this northern Colorado ranch, ranging in age from the Ice Age to the historical Indian tribes that occupied the ranch. The ranch was the home for Native Americans for close to 13,000 years, but the joy of discovery is not limited to finding the artifacts from these Native Americans, the ranch also has fossilized mammal remains.

Figure 1a. Location of metatarsal
bone on modern horse 
Figure 1 - Two fossilized metatarsals found at the
prehistoric site in northern Colorado. The shorter metatarsal is
broken. The largest metatarsal is 213 mm or 8.4 inches long.
       The sandstones around the ranch contain mammal fossils dating back through most of the Tertiary Era. One of the extinct mammals that I found fossilized bones from were prehistoric horses. Figure 1 is a photograph of two metatarsals I found near each other and near the Ice Age tool discussed in this blog. The metatarsals look like they are from a similarly sized horse or they could be from the skeleton of the same horse. From my books on prehistoric mammals and because I am a vertebrate paleontologist wannabe, I determined that these bones probably belong to a Pleistocene horse called Equus calobatus, a horse that roamed the high plains of North America from approximately 1.5 to .5 million years ago, well before humans entered the continent or showed up at this prehistoric site.

Figure 2 and 2a - Cheek teeth of prehistoric horse found near
metatarsals in Figure 1. Pattern of teeth consistent with
Equus calobatus.    

        Figures 2 and 2a show the fossilized cheek teeth from a prehistoric horse that I found near the metatarsals in Figure 1. The cheek teeth and the metatarsals may or may not belong to the same horse, but my amateur sleuthing tells me the cheek teeth pattern is consistent with that of Equus calobatus, the same species I believe the metatarsals are from 

Native Americans and their Horses
       It is a common misconception that since Native Americans became world renowned horsemen, they had always had horses throughout their long reign over North America, but this is not the case. The horse species that inhabited North America during much of the Pleistocene epoch went extinct at the end of the Ice Age like many of the other mammal species we have discussed on this blog. There is no archaeological evidence that Ice Age humans had much contact with Pleistocene horses in North America, except of course as the occasional menu item.

        It wasn't until the Spaniards arrived in western North America in the 1600s that the horse was reintroduced to North America and introduced to Native Americans. So from the time Native Americans entered North America across the Bering Strait or by boat from Europe, until the Spaniards showed up with domesticated horses, the main mode of transportation for Native Americans was walking.
                                                 Figure 3 - Artist's rendition of Pleistocene horse,
                                    Equus Caballus, that may have been around during Shadows on the Trail.

         At the time Shadows on the Trail took place around 10,700 years ago, there may have still been some Pleistocene horses running around, but ultimately they went extinct along with camelops, dire wolves, wooly mammoths, ground sloths, giant armadillos, sabre-tooth cats, and many other mammal species.

       Why did Pleistocene horses go extinct? This is the same debate scientists have over other species that went extinct. It could have been climate change, vegetation change, hunting pressure from humans, a meteorite, or disease. Who knows? I have attached a link to an interesting article I found on the extinction of these horses and how bison may have influenced their extinction.

Pleistocene Horses - What Happened to Them?