Early Humans & Bison antiquus

San Juan Fossils Offer a Key to Human Migration

Discoveries on a small island lead anthropologists to rethink the way early humans came to North America.

Anthropologists have long held, despite the insistence of Native Americans to the contrary, that early humans, known as “Clovis people,” came to North America from Asia via a land bridge. New evidence from Orcas Island is changing that narrative.

We now know that human activity on the San Juan Islands dates back to at least twelve thousand years ago. How do we know that? Well, in 2003, workers dug up some bones.

They happened to be the remains of the species Bison antiquus, also known as the Ayers bison, after the family’s land they were found in. The Ayers bison is an extinct form of bison common in North America until just after the extinction of other large mammals around 11,000 years ago. These bison were much larger than modern American bison, up to 9 feet tall.

These remains indicate the bison were present on what is now the island for over a thousand years, between 12,000 and 10,800 years ago. Sea levels were much lower then, and the island was likely connected to the mainland. The specimen found on Orcas Island was radiocarbon-dated to be from 11,990 years ago, during the last ice age. Most intriguingly, the bison specimen shows evidence of “on-site butchering” and the removal of the “choicest cuts.” There are impact points on the bones and marks from cutting, which point to human activity consistent with other bison sites throughout North America.

As the wetlands where these bones were found were highly acidic, and therefore tend not to preserve bone well, it is miraculous that these remains were discovered at all. It is also likely there would be more remains on the San Juans if the environmental conditions had been different.

These remains help rethink the migration patterns of early humans on the North American continent. Prior to the discovery of the Ayers bison, anthropologists theorized the earliest humans in the region were the Clovis people, identified by unique tools. However, the bison remains found on Orcas Island were dated to be 800 years older than the Clovis era, prior to when the land bridge would have been open. This led anthropologists to theorize that early humans migrated to North America not by a land bridge, which would have still been closed to overland travel, but perhaps by boats hugging the shoreline.

Little evidence has been found of extended human habitation on the islands prior to the modern era, but environmental conditions made preservation of artifacts unlikely. Still, we here at Island Histories are hopeful for the appearance of new archaeological evidence on the islands to shed light on this exciting moment in human history.