What Bison Teeth Reveal About Bison in Glacier’s Mountains

Bison have not lived in Glacier National Park since the 1800s, but their remains are still turning up, eroding out of creek banks and melting out of ice patches at elevations as high as 7,000 to 8,000 feet. In an NPS article, Kristin Vinduska tags along as park archeologists Kyle Langley and Brent Rowley collect some of them, to answer a question that is not often asked: how did bison use mountains?

The American bison once roamed across most of North America in numbers that reached into the tens of millions. NPS photo.

The question

The archeologists want to know how bison used this landscape over the last 10,000-plus years, and to learn more about the cooperative nature of bison hunting. They gather bison remains from eroding banks and melting ice patches and send them to a lab for two tests. Radiocarbon dating gives the age of the remains. Stable carbon isotope analysis shows what kinds of plants the bison ate, which hints at the elevations where they spent their time: a mountain-shrub diet versus a tallgrass-prairie diet, for example, would point to a bison that foraged in the mountains. Horns and teeth give the best results because they keep the carbon of the plants an animal ate through its life. Combined, the two tests show how bison traveled through the landscape in a given period.

Locations come partly from park staff who earlier found and recorded bison remains. Langley, whose graduate thesis mapped evidence of bison and bison hunting in Glacier using ArcGIS, says finding teeth in rugged, densely vegetated country is as hard as it is rewarding, and that the mapping is an ongoing project updated as new data come in.

Why collect when visitors are told to "Leave What You Find"? The archeologists explain that resource managers must decide how best to preserve the context of such resources. Remains about to erode out of banks or melt out of ice are about to lose their context, so collecting them now and carefully recording where they lay can show their age and use, including whether a spot may have been used to hunt bison, by looking for terrain that favored hunters.

Bison restoration efforts are under way in many places across the United States. NPS photo.

Bison and the people of the park

Evidence suggests bison used both open grazing land and the shelter of wooded mountains through the year, and some may have stayed in the mountains all year, where timber and grassland were both available. Physical evidence of human use in the park goes back more than 10,000 years. The land is part of the traditional and ancestral homelands of the Umsskáápipikani, Ktunaxa, Séliš and Ql̓ispé peoples, and Langley's thesis notes that bison and bison hunting are fundamental to the cultural systems of many Indigenous cultures of Montana, with songs, dance and ceremony tied to the hunt.

Almost all pre-modern hunting used terrain to the hunter's advantage, moving bison where they could not charge or escape easily. In Glacier that could have meant marshes, wetlands, meadows on sloped alluvial fans, frozen lakes and snowdrifts, or human-built corrals reached by a drive line. Bison jumps are unlikely locally, for lack of suitable terrain. Extreme overhunting in the mid-1800s, as settlers moved through, nearly drove the species to extinction.

Today the Blackfeet Nation is working to bring bison, iinnii, back. In 2009 leaders of the four tribes of the Blackfoot Confederacy (the Blackfeet, Kainai, Piikani and Siksika Nations) created the Iinnii Initiative to conserve traditional lands, protect Blackfeet culture and make a home for bison to return to. The Blackfeet Nation Bison Reserve now holds around 800 bison. The first 88 came from Elk Island National Park in Canada and are descendants of bison from this area who were sent there over a hundred years ago. One goal is to let bison roam freely again and return to Glacier.

What the tests found so far

In August the archeologists sent 22 samples, 16 teeth and 6 bones, to the University of California, Irvine's Keek Carbon Cycle AMS Program. Radiocarbon ages carry a margin of error of plus or minus 15 years, and the isotope analysis also helps confirm the dating.

Horns and teeth give the best lab results for age and diet. NPS photo.

• Two teeth from Many Glacier were about 180 years old, from around the mid-1800s, and one was just over 2,000 years old.
• The oldest tooth, from a high alpine snowfield in the St. Mary area, dates to about 4,400 years ago.
• Many samples from an archeological site in the Belly River all dated to between 1,000 and 1,100 years ago.
• An initial look at the isotope results suggests the bison fed mostly on C3 plants rather than C4, which fits higher alpine vegetation, so bison in Glacier may have spent most of their time in the park rather than out on the plains. The full isotope data, which factor in local grasslands, were expected the next spring, and comparing them with modern bison populations would firm up the picture.

Samples came from six geographic locations, and park staff hope to continue the study with more samples from more places if funding is found. Langley says bison should be one of Glacier's iconic animals alongside the grizzly bear and mountain goat, and that this research helps correct the near-absence of that association by proving that bison were here.

Bison remains give clues about the bison who once roamed in and around Glacier National Park. NPS photo.

Sources

• Kristin Vinduska, National Park Service, "Uncovering Ungulates: The Search for Bison in Glacier", https://www.nps.gov/articles/000/uncovering-ungulates-the-search-for-bison-in-glacier.htm; rewritten in hubnx's own words.