Elders of Wahpeton Dakota had long campaigned to have Plains bison reintroduced to their lands as they believed it would bring good fortune to Canada’s First Nations people. When officials at Wanuskewin Heritage Park finally agreed to reintroduce the animals in December 2019, more than 100 years after they were nearly hunted into extinction, it did not take long for something astonishing to happen.

Just eight months after the bison were released, they uncovered a series of ancient rock carvings, or petroglyphs, and the tools used to create them around 1,000 years ago.

The park’s chief archaeologist and co-founder, Ernie Walker, made the discovery with the park’s bison manager Craig Thoms near a spot where the bison take dust baths. When Walker first noticed the grooves cut into the rocks, he assumed that it was a mark made by a modern tool. But brushing the dust away revealed more markings like them, and he realized he was looking at something quite different.

“They were all parallel, all symmetrical,” Walker told the Smithsonian. “It was at that point I realized this [was] actually what is known as a petroglyph. This was intentionally carved.”

In rolling around in the earth, the bison had revealed what is known as a “ribstone”—a 550-pound boulder carving depicting bison’s ribs. Further investigation led to the discovery of three further carvings, one larger stone with a grid carved pattern, a smaller example marked with pits and grooves, and 1,200-pound boulder engraved with lines. Experts have dated the carvings at around 1,000 years old.

“We’d found the detritus of everyday living: broken stone tools and debris from the manufacture of stone tools, bones, charcoal, potsherds, seeds and things like that,” Walker said. “But [we] didn’t find ideas. [We] didn’t find emotions. The petroglyphs brought that. They’re that other dimension. They’re a glimpse into somebody’s hopes and dreams.”

Perhaps the most stunning discovery was a stone knife used to create the petroglyphs as though the artist had just downed their tools mere moments, and not hundreds of years, ago.

“The elders used to tell us when the bison come back, that’s when there’ll be a good change in our history,”  Wahpeton Dakota Elder Cy Standing said. “We’ve been down a long time. But it feels like we are starting the way up.”

The park has a long-standing relationship with the First Nations people whose heritage any archaeological investigations involve. On finding the petroglyphs, the staff invited park elders in to offer spiritual guidance in what to do with what they had found. While First Nations beliefs hold that all rocks are sacred and should not be moved, they conceded that to preserve these unique, ancient carvings, they could be moved into a museum.

“You know, we don’t really know our history. We have oral history,” said Standing, “… but all the books were written after contact. [The petroglyphs] show us more. We had a good life. Our children need to know that so they can go forward.”