The grizzly bears feasted on piles of spilled wheat and barley. They broke into grain bins. They helped themselves to apples from family orchards. Sometimes they massacred chickens or picked off calves.

Once nearly eradicated from the Lower 48 United States, grizzlies are growing in population and spreading onto Montana’s plains, where they had not roamed in perhaps a century.

In their travels, they’ve acquired a fondness for the good eating to be found in farmyards.

This is a grave problem for both humans and bears. The safety of farmers and their families is at stake, and so is the survival of the bears, which could get themselves killed by threatening people’s lives and livelihoods.

Enter the bear dogs.

Farms are not the only places where grizzlies are showing up, and all those bears, understandably, have humans very worried.

As conflicts have increased around the state, so have calls to remove the bears from protection under the Endangered Species Act, including through current legislation in Congress aimed at a population of bears to the south, around Yellowstone National Park.

Removing federal protection would let the state hold a hunting season for grizzlies, which many Montanans see as necessary.

“There are too many bears,” said Mike Leys, who owns a bear dog named Patton and runs a farm near Choteau, Montana. He said he wished farmers could shoot problem bears that come on their property.

But amid the controversy, dogs are an important strategy in a complicated quest for coexistence, according to a growing number of researchers and farmers. By keeping the bears away from farms, dogs can help prevent conflicts before they start.

“The bear dogs are there to basically change the calculus in the bear’s head,” said Wesley Sarmento, a former bear manager for Montana’s wildlife agency. “To switch it from these farms being a place where they’re getting benefits to being now a place of risk.”

Sarmento, whose job was to keep humans and bears safe by keeping them apart, found his way to the dogs out of desperation. The calls and texts from farmers wouldn’t stop, and nothing seemed to work to keep the bears away.

Among the frequent callers were Steve and Julie Ahrens, who’ve been farming wheat, barley and chickpeas outside Shelby for more than 40 years. Before that, Steve Ahrens’ grandfather worked the same land. They had never seen a bear on the farm before 2019.

By June 2020, they had four grizzlies visit in a single week.

They texted Sarmento a lot, and he tried his best to dissuade the bears. Here’s what didn’t work: cleaning up grain spills (all but impossible on a working farm). Trapping and releasing near Glacier National Park (the bears came back). Alarms on the grain bins (the bears ignored them). Electric fencing around the bins (it kept the bears out but was a big nuisance for the farmworkers).

Then, in 2020, he heard from a farmer whose bear problems suddenly improved after his son brought home a stray dog.

It was a breed of livestock guardian dog. They’re put out to live with sheep, poultry and other farm animals to protect them from coyotes and other predators. But this dog was doing something a little different: Living with people and chasing bears off the property, even mothers with cubs, which are notoriously dangerous.

He partnered with Julie Young, an ecology professor at Utah State University, to investigate whether dogs could really keep bears out of farmyards. They decided on three Turkish breeds, all shepherds: the Kangal, the Boz and the Anatolian. The dogs cost about $700 each, paid for by the study.

As lethal as grizzly bears can be, they generally prefer to avoid prey that’s not easy to kill, experts say, which is why dogs can drive them away. “They’re just like, ‘OK, never mind, you’re barking at me; I’ll leave,’ ” Young said.