BILLINGS, Mont. - The war on wolves took a strange twist in the winter of 1905.
After two decades of paying bounties for hundreds of thousands of dead wolves in Montana, the Legislature approved a new law - "to provide for the extermination of wolves and coyotes" - dabbling in the emerging practice of biological warfare.
The idea was simple and cheap: capture wolves and coyotes, infect them with mange and send them back into the wild.
Eventually, the theory went, the animals would return to their packs and spread the highly contagious and sometimes fatal disease, which causes animals to itch so feverishly they lose hair.
The disease, caused by a tiny skin-burrowing mite, can leave wolves emaciated, staggering and susceptible to hypothermia, infections and other health problems.
Eastern Montana saw "unqualifiedly splendid results" and reports of hundreds of dead and diseased wolves, said Morton E. Knowles, state veterinarian at the time of the program.
He recommended the technique to others.
"The predatory pest question so far as coyotes and wolves are concerned will be settled for all time," Knowles wrote to the Breeder's Gazette, a farming and ranching magazine, in 1914.
Now, 102 years after the Montana law was passed, the same disease is threatening wolves in the country's signature population in Yellowstone National Park.
Earlier this winter, wolf biologists found the aging alpha male of Mollie's pack stricken with mange. About 40 percent of his body hair was gone. The 9-year-old wolf hasn't been seen for weeks and may already have died, park officials said.
It's unclear exactly how he got it but, now that it has arrived in Yellowstone, there's a concern that it could take hold in the park population where wolves intermix regularly, said Doug Smith, leader of the Yellowstone wolf project.
Unlike other canine diseases such as distemper and parvo, mange can be a persistent and unpredictable threat with varying degrees of mortality.
"Mange would be around in a messy kind of way every year," Smith said. "This is an exotic, introduced disease we want to eradicate - but it may be impractical to do so."
Though the disease has been around for years in coyotes, foxes and other animals, Yellowstone officials had hoped it would never make it across the park's borders.
Mark Atkinson, a wildlife veterinarian for the Montana Department of Fish, Wildlife and Parks, said the disease can take a toll on individual animals but shouldn't affect the long-term outlook for Yellowstone's wolves.
"The immediate effects of an outbreak can be severe," he said. "But in the long run, it's not a disease that impacts stable populations."
Some have speculated - but it would be impossible to prove - that the mange seen today is related to Montana's effort to use it against four-legged "pests" early last century.
19th-century wolf bounties
Wolves once roamed North America from northern Canada to central Mexico.
Lewis and Clark frequently spotted wolves in Montana and elsewhere as they tagged alongside bison herds.
For early explorers and settlers, wolves were more of a nuisance than an outright enemy, said Tim Lehman, a Rocky Mountain College professor who has studied the history of wolves and settlement in Montana.
But as bison populations fell and cattle began to dominate the landscape, the pressure against predators intensified. At the time, there may have been more wolves than people in the state. Canids roamed in large groups, killed livestock, hurt the state's ranching economy and became a feared stalker of the plains.
"That's really the transition for the end of wolves," Lehman said.
Montana's first bounty law, passed in 1883, paid $1 for every pelt. Within the first year, 5,450 wolf hides were collected.
Soon, a cottage industry of "wolfers" cropped up. Between 1870 and 1877, they killed more than 55,000 wolves a year, according to a 1986 article in Montana Magazine by Dave Walter, reference librarian at the Montana Historical Society.
Bounties fluctuated over the years, reaching a high of $15 in 1911.
Between 1883 and 1918, Montana paid $342,764 in bounties for 80,730 wolves, the article said.
The war on wolves was escalated in 1901 with a change in the law allowing bounties for wolf pups, which allowed wolfers to directly target dens, Lehman said.
Lawmakers, though, went looking for another, cheaper way to destroy wolves and coyotes.
Mange introduced as killer
The March 1905 law required the state veterinarian to capture six wolves and six coyotes in eight counties, infect them with mange and then send them off "in six different directions - not less than eight miles away in each direction."
Lawmakers set aside $2,500 to implement the program.
Two days after the law passed, The Billings Daily Gazette ran a story with the headline, "Governor signs bill for an innovation in state's warfare on predatory animals."
The law is a "new departure" in "exterminating the wolves and coyotes that have been the cause of so much loss and trouble to herdsmen and flockmasters."
Documentation of the experimental program is scant, limited mostly to correspondence from the state veterinarian and a few others. One researcher in the 1960s speculated that records may have been destroyed because it was controversial.
Knowles, Montana state veterinarian from 1896 to 1913, wrote in a letter to Breeder's Gazette in 1909 that about 200 wolves and coyotes had been infected and released and that some of them may have reached Wyoming or South Dakota.
He said he had received written and verbal reports that "several hundreds" had died.
"I am constantly receiving reports from all over the state of Montana of stockmen finding dead or badly diseased wolves and coyotes that are easily killed, many of them being destroyed by a blow from a club, being so poor as to be unable to get out of the way," Knowles wrote.
Ranchers in eastern Montana said 95 percent of the remaining wolves and coyotes were "affected with the disease" and that bounty hunters "have practically abandoned that territory," Knowles reported in 1913.
The Federal Bureau of Animal Husbandry apparently opposed Montana's mange program out of concern that the disease might spread to livestock, according to one researcher.
Knowles said the federal agency thought the program to be "extremely dangerous, probably inimical to food-producing animals."
The experiment ended in 1916. Although it had some success, wolves weren't eliminated from Montana until the 1930s.
Montana isn't alone in its attempt to use disease as a weapon against wild animals.
Ground squirrels were infected with tularemia in California in the early 1900s in the hope they'd spread it to rodents, and parvovirus was used to reduce a feral cat population on a sub-Antarctic island in 1977.
In Australia, millions of rabbits - descendants of those introduced for sport hunting the 1859 - died after government agents in the 1950s released a mosquito- and flea-borne virus called myxomatosis. The experiment wiped out more than 95 percent of the rabbits, but the population eventually built up a resistance.
Tinkering with biowarfare can have unintended results.
In 1952, a man in France, upset at seeing rabbits chew through his garden, infected them with the same virus used against the Australian rabbits. Within a year, it had spread to more than a half-dozen neighboring countries in Europe.
"These things can have major, long-term and unforeseen consequences," said Milton Friend, a retired scientist and former head of the U.S. Geological Survey's National Wildlife Health Center in Madison, Wis. "Nothing is ever simple."
Mange threat persists
Though it's widespread today, the origins of mange are difficult to track.
One theory holds that it started as a human parasite, was transmitted to domestic animals, and eventually made it into the wild and onto every continent.
Descriptions of the Montana mange experiment don't mention where state agents got the disease-carrying mites or exactly how they infected others.
It probably was already in the environment, but it's impossible to know where and at what levels because records are so spotty, wildlife officials said. That's part of the reason it would be difficult to determine whether mange from Montana's program was the main contributor to today's disease in coyotes, foxes and wolves, Friend said.
Mange in the Northern Rockies wolves, which were introduced in 1995 and 1996, was first confirmed in 2003. Wildlife officials say they probably got it from coyotes or foxes.
Since then, most of the cases have been reported east of the Continental Divide in Montana and Wyoming.
In 2005, at least 11 packs had infected wolves. The number dropped to four or five last year, according to Mike Jimenez, a U.S. Fish and Wildlife Service wolf biologist who has been tracking the effects of mange.
Some wolves survive mange; others don't. It depends on several factors, including the health of the animals, the elevation where they live and the severity of winters.
In severe cases, mange reduces a healthy wolf or coyote into something akin to a large, shaved rat.
"It's definitely hard on pups," Jimenez said.
The Absaroka pack east of Yellowstone was wiped out several years ago by the disease. Others have died, too, Jimenez said, but not nearly enough to be considered a major or long-term threat to the wolf population.
Mange can be treated in domestic dogs but is much more difficult in the wild, primarily because treatment requires multiple vaccine doses, a difficult prospect for hard-to-track wolves.
The story of mange in wolves in the Northern Rockies shows people's changing relationship with nature in microcosm. A deadly parasitic disease once spread to wild animals at the behest of government is now studied at government expense as a threat to an important natural resource.
Today, rather than spending $1 or $15 for dead wolves, the federal government spends about $3 million a year to keep about 1,200 wolves alive in the wild in the Northern Rockies.
Some things haven't changed, though. Canis lupus still stirs controversy, and the microscopic mite that causes mange is still out there.