News and Events

News Archive


Friluftsliv: Bones help solve a 12,000-year-old mystery

Posted 3/07/23 (Tue)

By Doug Wurtz

To loosely translate from Norwegian to English: fri = free, lufts = air’s, liv = life
The English equivalent= Outdoor Life

I’ve always been fascinated by bones. My study of them began after my introduction to archaeology in the summer of 2006.

The project that summer was a 12,000-year-old PaleoIndian bison kill site. I wrote about that project, Beacon Island, in my last column.

On a late fall to early winter day 12,000 years ago, a group of hunters surrounded and killed a minimum of twenty-nine bison. They weren’t the bison that we see in the North Dakota Badlands. The genus and species name for the bison they encountered that day is Bison antiquus. This ancestor to the modern bison, Bison bison, was twenty-five percent larger than the modern-day animal. It was seven and a half feet tall, fifteen feet long, and weighed about 3,500 pounds. It was a formidable animal for these hunters to successfully harvest for food.

The final archaeological report for Beacon Island summarized many aspects of the project: topography, soil types, tool types, ornaments, mollusks and more. A large portion of the final report pertains to the bone analysis.

As mentioned above, it was determined that a minimum of twenty-nine bison were killed in the late fall or early winter twelve thousand years ago. How that was determined is what fueled my interest in the study of bones.

The initial dating of the kill site is quite straight forward. Using radiocarbon dating of charcoal and bone from the site, archaeological specialists were able to determine the approximate date of the event: 12,260 years ago +/- 95 years.

They were also able to determine that the event happened in the late fall to early winter by dating bison teeth found during the excavation. Bison calves in this region are born from late March to May. It was determined that bison calves killed during the event were 31 to 36 weeks old. Calculating forward thirty plus weeks from late March reveals a late fall to early winter kill date. Again, using bones retrieved from the site, archaeologists were able to determine the number of animals that were harvested that day, twelve thousand years ago. This was done by isolating and counting one particular bone. That bone is called the astragalus or talus bone. It is one of the bones that comprise the ankles of mammals. The bone structure of all mammals (humans, bison, whitetail deer, goats, etc.) is very similar.

Bison have two astragalus (ankle) bones: a right and a left astragalus. They are distinctly either right or left so by isolating and counting just the right astragalus bones collected at the site, it was determined that, at a minimum, twenty-nine animals were killed that day.

The study of bones (osteology) can be fascinating; how they form, how they fit together, and how they support an animal as large as an ancient Bison antiquus that weighed up to 3,500 pounds.

Bones also allow archaeologists to solve 12,000-year-old mysteries such as the one at Beacon Island.

Doug Wurtz grew up near Ryder and graduated from Minot State University. His retirement activities include nature photography as well as serving as a Certified Interpretive Guide for the State Historical Society of North Dakota. He is past president of the North Dakota Archaeological Association. Doug and his wife, Linda, live in Bismarck.