A new way of dating a pile of ancient bones and stone tools is shedding light on the mysterious lives of the first Albertans.

A prehistoric site where people hunted horses and camels along what is now the St. Mary River in the province's south is centuries older than previously thought, said University of Calgary archeologist Brian Kooyman, co-author of a paper published Monday.

That means the 13,300-year-old bones, along with stone choppers and knives used to butcher the animals, predate what was thought to be North America's first identifiable ancient culture.

"It's quite awe-inspiring to stand there and know that these are the first Albertans," Kooyman said.

"We can see the butchered bones and we can see the tracks of the animals. We can actually see the footprints of camels and horses. It's like they were here yesterday."

It's the completeness of the site that makes it unique.

It features the bones of seven horses and one camel -- an animal that originated in North America and died out at the end of the ice ages. There are a variety of crude choppers and knives chipped from stone.

There's no doubt the bones are the remains of a successful hunt.

"We have cut marks on horse bones and camel bones," said Kooyman. "You can even see what people cut them up into, like roasts."

The site was originally found in 1999 by a schoolteacher out for a walk with his family. Normally submerged by the St. Mary reservoir, the spot known as Wally's Beach was exposed by that year's low water. The prairie wind blew away much of the dirt around it and left the artifacts in high relief.

Kooyman excavated and studied the site, but contaminants in the samples originally led to a too-recent date, which was only corrected with more accurate radiocarbon dating. The new age, about 300 years older, led to Monday's paper in the Proceedings of the National Academy of Sciences.

The site offers haunting clues about the lives of those ancient hunters.

The area hasn't changed too much from all those thousands of years ago -- a ramp on the riverbank where animals would have come to drink. Kooyman guesses it was a kill site for a small group of hunters.

"What we're probably looking at is something like three or four families of related people moving and working together as a hunting and gathering group.

"They probably waited and ambushed them. They've probably been in the area long enough and have an understanding of the animal behaviour enough, that they know where to target.

"We can actually see what they were doing. They're hunting systematically and successfully and more than one animal species. I don't think there's anything really like it."

Kooyman said scientists have long thought members of the Clovis culture, marked by its long spearpoints, were the earliest identifiable group to people North America. While other sites had hinted at an earlier society, Wally's Beach is the proof, he said.

"I'm standing there and looking at a revolution in my understanding of things."