The image of an Indian bowhunter aiming at a herd of buffalo has captivated motorists along Interstate 25 in Westminster for the past year, evoking much mystery and speculation.

A graffiti artist, using a subtle palette of black and charcoal, spray- painted the scene over six pieces of concrete culvert left behind after an urban drainage and flood-control project. The buffalo roam through a broad, wheat-colored field fringed by the Rocky Mountains, a bit of the Old West with a Lowe’s and a Walmart as its backdrop.

Some interpret it as a sociopolitical statement on suburban life; others say it’s a comment on current economic conditions; and still others believe it is rooted in Paleolithic rock art.

Graffiti artists usually prefer to remain anonymous, so the intentions of this artist — whose tag is Karma — are unknown.

Still, opinions are as abundant as the nearly 100,000 cars that travel past the work most days.

“It’s kind of cool when you look at the hunter and realize he is looking at all these buffalo with the mountains in the background, like something that could have happened 150 years ago,” said Damon McLeese, executive director of Access Gallery in Denver, which runs the Street2Studio anti-graffiti art program for teens.

When photographer Richard Cargo of Mead first saw the piece while driving down the highway, it reminded him of his youth when he would go bow-hunting in the mountains near Lyons.

Now, it brings something else to mind.

“Right now, because of the economy, a lot of people in this particular area just leave stuff because it’s cheaper to leave than haul away,” he said. “It was an eyesore, but someone goes in and uses it as canvas, making something good out of something bad.”

Graffiti art has long been controversial, and many consider it vandalism. The website of the Graffiti Removal Program of the Adams County Sheriff’s Office says “graffiti negatively affects an area visually and encourages other criminal behavior.”

The art world has begun to see it differently.

When the Los Angeles Museum of Contemporary Art launched “Art in the Streets” last year, the first major U.S. museum exhibition on the history of graffiti and street art, it proved the most popular show in the history of the museum.

And the Longmont Museum’s show “Street Cred: Graffiti Art from Concrete to Canvas” was a stunning success.

“We had the biggest opening ever,” said director Wesley Jessup.

Conversations with the public throughout the show, which closed recently, “allowed people to understand graffiti from a wider perspective,” said Jessup, “not some of the things we get hung up on so quickly when we think of graffiti.”

The buffalo graffiti art, by an anonymous artist in a random field, doesn’t have the stamp of museum approval, and Jessup doesn’t know if it’s legal.

Still, he loves it.

“It’s great,” he said. “I’ve never seen these kinds of animal figures or subject matter in graffiti before.”

Gene Binder, owner of a contemporary art gallery in the West Texas art mecca of Marfa, believes the mysterious work may have been inspired by Paleolithic cave paintings in southern France.

Created 30,000 years ago in Chauvet-Pont-d-Arc, the cave paintings depict animals of the hunt: bison, reindeer and bear. The ice-age artists used the existing contours of rock surface to heighten the sense of perspective and movement.

“It’s great that the contemporary artist chose to use unpretentious concrete sewer pipe to accomplish (this piece), which appears to be randomly placed in the field as a herd of buffalo might be grazing as they are stalked by an Indian hunter,” he said.

“This is far better than 95 percent of the public art I’ve seen, and at no cost to the taxpayers.”

Colleen O’Connor: 303-954-1083 or coconnor@denverpost.com