WATERFORD, Maine — On a sprawling, upland pasture, where docile cows long grazed, a newer tenant occupies the field. They are neither soft nor cuddly. In fact, the owners of Beech Hill Farm & Bison Ranch are so buffaloed by their herd that they keep a respectful distance.

“We consider each one dangerous,” rancher Ted Colburn said.

The mighty American mammals that can weigh a ton and charge at 30 mph are not pets, though Colburn and his wife Doretta have named a few.

Bison farming is what the couple call a “life-extension program.” Every morning they rise early and plan their day over coffee. Compared to cattle raising, bison rearing is hands off. They feed on grass during the summer and organic hay during the winter. Pasturing 23 bison is an active, full-time pursuit. Maintaining fencing and caring for an abandoned calf keeps them busy when they aren’t growing organic vegetables, pruning fruit trees and tending their 47 rolling acres.

“They have a good life while they are here,” said Ted Colburn, who purchased the buffalo farm from his cousin in 2007 and moved here from Connecticut for a new adventure. “They have resort living,” he said. “Their owners do not.”

“There is not a day that we don’t wake up and look out to see where the bison are,” Doretta said. “You have to be ever vigilant.”

Bison on the rise

According to the National Bison Association, bison is staging a major comeback.

“Today, roughly 400,000 bison now roam the pastures and rangelands across North America, and more than 90 percent of those animals are on private ranches,” association’s website states.

Demand in bison has grown in double digits for the past five years. Many point to media mogul Ted Turner, who has a string of bison ranches and successful Ted’s Montana Grill restaurants serving bison burgers and meatloaf.

In Maine, free-range chicken and grass-fed beef have long been the darlings of the locavore scene. But free-range bison, feeding on grass high above the western Maine lakes and down south on a 1650 farm in Berwick, is quietly making inroads.

Ranchers including the Colburns and Conor Guptill of Hackmatack Farm in Berwick are compelled to sustain this wild species that once roamed the great plains by the millions. By increasing interest in meat, hides and coveted bison hearts — a delicacy — they are bolstering the nascent bison market.

This fall the Colburns will harvest a small portion of their herd and sell the meat — a cleaner tasting, lighter and healthier beef alternative — from their Waterford homestead. Customers are already licking their chops. They sign up for fresh bison meat months in advance. When that runs out, the couple make sure to have bison cuts from Wisconsin on hand to meet demand.

“Every year we get new customers learning about the quality of bison meat and grass fed,” Doretta said. “The change in the way we eat and look at food has a good impact on us.”

Meanwhile, other bison ranchers, such as Stephen Hobart of Breakneck Ridge Farm in Abbot, are abandoning farming buffalo all together.

“Not everybody can do it. It can be a challenge,” said the 63-year-old, who is retiring after running a successful bison business since 2001.

“I am turning away customers all the time. My market is based on meat,” said Hobart, who had no problem selling off his herd to startups eager to rear the self-sustaining animal.

Pluses are many, but so are dangers

Because bison, also known as buffalo, is not yet a culinary mainstay in Maine, education and marketing are chief among ranchers’ tasks.

For consumers, the benefits of bison meat — loaded with vitamin B-12, Omega 3s and vitamin D — are many. Farmers breeding and raising these wooly, wild, horned creatures find it “can be a little bit risky,” said Doretta, who keeps a watchful eye and stays on the other side of the fence. “You have to know what you are getting into.”

Hobart was a mentor to the couple. He shared tips and tricks learned in the field. When they took over the business, Beech Hill bison were partially grain fed. Hobart, an advocate for grass-fed only, clued them into this healthier approach, which hinges on pasture rotation. Beech Hill’s bison now have access to seven connected fields.

“We didn’t know anything about raising animals before other than cats and dogs,” Doretta, an ordained minister, said. “You go on your gut, you learn, you listen, you observe.”

Still, intuition and common sense are the best ways to avoid agitating these hoofed animals, which could kill a human with a thrash of their giant heads.

The Colburns, who “like to eat well and share ideas with people,” take pride in knowing they are helping preserve these majestic animals, considered — like eagles and coyotes — to be sacred by native people.

“We feel like we are part of the process,” Ted, who gives tours and talks to the public, said. “They are a wild animal. Let’s keep them wild. It’s for the best.”

By doing so, Ted is continuing his family’s farming tradition, which stretches back to 1900, when his great-grandfather and grandfather bought the rambling, sloped land with views of the Mahoosuc Range and turned it into a dairy farm. Back then butter, not bison, was the export du jour. The retired Coast Guard captain, who remembers working on the farm as a boy, never thought he’d be corralling bison here at 68.

“I spent time here in the summer, milking cows and fetching eggs,” he recalled.

Down south, 29-year-old Conor Guptill is fired up about about bison farming’s regenerative aspects. The new buzzword in farming circles is an evolved form of sustainable farming. And bison, which roam outside all year, act as natural fertilizers. They fit the trend to a T.

“Regenerative farming reverses the effects of global warming by putting carbon back into the soil,” Guptill said. “We don’t want to just maintain the status quo but improve the landscape.”

Did bison naturally find their way to Maine? It’s hard to know.

On Beech Hill Farm’s pastures, jumping bulls and galloping calves of all ages seem right at home. As the herd saunters through a corral, one calf named Calisa Grace hangs by the fence. The Colburns, who started bison farming in 2008, had to bottle feed the calf because she was abandoned by her mother this summer.

“She would have starved to death,” Doretta Colburn said.

Although bison require little maintenance, they are outside all the time, birth on their own and are natural foragers, the Colburns remain vigilant. They know who is the dominant animal in the herd, and if they need to go into the pen to break ice-covered water bowls in the winter, they do it fast. “These are wild animals, you cannot make them a pet.”

Although clearly demanding, bison farmers, from young to seasoned, are intrigued by these beasts.

“They are incredible animals. You don’t pet them, but they are fascinating — very intelligent,” Doretta said. “It’s been an incredible experience.”