Bison DNA Study Rewrites 200,000 Years of History. Here's What It Means for Their Survival

Fort Smith, Northwest Territories, Canada, MMN Correspondent: For much of American history, the bison was more than an animal. It was a moving landscape. Before European settlement, an estimated 50 million bison ranged from Mexico to Canada. Their hooves stirred the prairie, and their presence shaped the lives and stories of Indigenous peoples across the continent. Today, roughly 530,000 bison remain. The numbers alone don't tell the real story. A new study in Science, built on 160 ancient and modern bison genomes, does. Scientists have long known that bison crossed from Siberia into Alaska around 200,000 years ago. They spread quickly, filling nearly every corner of North America. What the new genome work reveals is that these early bison stayed connected. Herds from one coast to another exchanged genes so freely that they remained almost indistinguishable across the continent. That genetic flow was likely a source of strength. It allowed bison to adapt and persist through major climate shifts and changing landscapes. The species did experience narrowing moments. The first came when bison entered the continent. Another followed around 20,000 years ago during the Last Glacial Maximum. And then came the 19th century, when westward expansion, railway construction, and policies that dramatically altered Indigenous ways of life reduced bison numbers drastically. By 1890, roughly 500 bison remained in scattered groups. The surprise? Those 500 carried far more genetic diversity than expected. The close call did not instantly wipe out the species' variation. That variation is now the focus of conservation work. Modern bison herds are small and separated, often fewer than 1,000 animals. In genetics, 1,000 is a meaningful threshold. Below that, herds risk inbreeding and losing the flexibility to handle disease or environmental change. Without natural pathways for gene flow, maintaining healthy herds requires deliberate help. One of the study's biggest revelations concerns bison subspecies. For decades, researchers debated how long ago wood bison and plains bison split. The new DNA evidence places that split around 3,000 years ago. Wood bison developed a larger frame and distinctive shoulder hump for boreal forest life, and plains bison roamed open grasslands. In the 1920s, Canadian conservation managers moved nearly 7,000 plains bison into Wood Buffalo National Park, where the two groups interbred. Today, every wood bison carries some plains bison DNA. The pure wood bison lineage, under the old definitions, no longer exists. Another twist involves cattle. In the 1870s, ranchers in Texas experimented with bison and cattle hybrids. Some of these hybrids found their way into wild herds. A 2022 paper suggested that no bison alive was free of cattle DNA, a claim that spurred widespread discussion. The new genetic analysis, based on 45 modern bison genomes, offers a more reassuring view. Roughly a third carry cattle genes, which means a majority do not. These findings are already shaping practical action. The Bison Integrated Genomics Project, or BIG, brings together scientists, government agencies, and Indigenous communities around a common goal: building a biobank of bison sperm and eggs. This frozen insurance policy preserves genetic material from diverse herds and allows future reintroduction into populations that need it. In vitro fertilization in bison has been possible since 2016, with success rates around 10%, compared with 30% in cattle. Indigenous communities are central to this work. For many, bison are relatives, not resources. The Lakota writer John Fire Lame Deer captured that bond in 1972: "The buffalo was part of us, his flesh and blood being absorbed by us until it became our own flesh and blood." That connection matters today. When researchers asked to collect samples from the Ronald Lake herd in Alberta, which numbers fewer than 400 animals, the Athabasca Chipewyan First Nation took time to consider. Lori Cyprien, a land and resource manager, eventually embraced the idea. She said, "If there was a really bad season, drought, wildfires, disease, our whole herd could get wiped out. If we have their genes in a biobank, at least part of them would still be here." The genetic story of the bison reaches beyond history. It is a guide. Fayelynn Scheideman, a doctoral student studying bison genetics, puts it simply: "I would rather have bison that are robust and genetically diverse and resilient than focus on purity." The emphasis now is on resilience. Bison need enough diversity to meet the future, whether that means changing climates, emerging diseases, or shifting habitats. The work unfolding now brings together scientific tools and Indigenous knowledge, and it treats bison as partners in their own recovery. For anyone who has seen a bison herd move across open land, the stakes are clear. This species has survived the Ice Age, the end of free-ranging herds, and the twists of human intervention. The next chapter depends on the care, science, and relationships built today. The bison's past is written in their DNA. Their future is being written by us.