A few weeks ago, highly trained cadaver dogs were set loose near Almo to search an area about the size of two football fields sniffing for human remains.

Usually the dogs’ missions involve recent crime scenes or missing children, people absent a month or so. But on this outing, the cadaver dogs from Driggs were looking for burial sites of emigrants at the City of Rocks National Reserve who were rushing for gold in California from 1849 to 1860, but didn’t quite make it through Idaho alive.

To the incredible nose of three German shepherds, whether a person was buried last week or 500 years ago, doesn’t matter. When the dog detects the smell of humans in the soil, it pauses and sends a signal to its handler – a sit down, lay down or perhaps a paw at the soil – then continues to search. To the dog it’s all a game. and its reward is to play with its favorite toy.

“A couple of areas our dogs definitely, based upon their body language, found the smell of human remains,” said Deb Hurlburt, who trains cadaver dogs and works closely with regional search-and-rescue and crime units. “You can tell those changes in body behavior, and they will convey a lot of information through searching if they are working the odor of human remains.”

Cadaver dogs work cheap.

“They love their toys,” Hurlburt said. “For this work it’s a ball. They love the work. The ball is the end all be all. It’s the huge paycheck for them.”

Experts on the Oregon-California Historic Trails and City of Rocks National Reserve archaeologists had identified two possible grave sites along the California Trail in the Circle Creek area of the park. About 6 miles of the historic trail passes through City of Rocks. They brought in the cadaver dogs in hopes of confirming their guesses. After the dogs confirmed the two sites as having human remains, they went on to locate another possible five more burial sites the experts didn’t know about.

“It wasn’t a surprise,” said Tara McClure-Cannon, assistant park manager at City of Rocks. “We had suspected some of these areas in the past based on what they looked like. The dogs were partly confirming our suspicions. We won’t know for sure unless we move forward with any sort of further work in the area. We have some suspicious rock piles that the dogs indicated on.”

Usually when an emigrant died along the trail, fellow travelers would cover the grave site with rocks and sometimes a stone with a name on it. Jerry Eichhorst, president of the Idaho chapter of the Oregon-California Trails Association helped identify some of the recent finds. He said there are thousands more buried along the 5,000-mile-long trail.

“About 250,000 is a pretty fair estimate of people that went to California, about 50,000 went to Oregon,” Eichhorst said. “Of that 250,000 there would be maybe 30,000 that went the Salt Lake alternate (route), so they didn’t go through City of Rocks, but you’re still going to have well over 200,000 people that went through City of Rocks. It’s estimated that there’s a person buried every quarter mile to every half mile. Just depending on the accounts in the stories and such.”

Eichhorst is a diary reader. He and his chapter have gathered about 2,700 diary entries from emigrants. Some of these diaries led him to the burial sites at City of Rocks. Others have helped make other historic finds.

“Several years ago I found a diary that referenced writing their name on some rocks at City of Rocks that we’ve never found names on,” Eichhorst said. “I told Wallace Keck, the park manager, about it and sent him the diary. He went out and was able to climb up these rocks and find names on it.”

Some rocks at City of Rocks famously have emigrant names written on them with wagon wheel axle grease.

Eichhorst said he is excited to tryout some newer technology called “LiDAR,” and acronym for light detection and ranging. The technology uses laser beams to create a 3D representation of a surveyed environment. It could detect words from old, worn rocks once placed on grave sites or other fascinating uses.

“You can use it from, say, a helicopter, and basically identify the ground and eliminate all of the trees and vegetation, so they use it down in Central America, for instance, looking for pyramids and other structures under the forest,” he said. Eichhorst said he’d like to persuade some Idaho university students to test the new technology on some sites along the historic trails.

McClure-Cannon, who started as an archaeologist at City of Rocks, said now that potential grave sites have been confirmed by the cadaver dogs, the park has a few options with what to do next. One possible step is to bring in ground penetrating radar equipment to scan over the grave sites. In rare cases, sites might be excavated. At the very least, sites will be marked with a GPS location by the park and locations kept from the public.

“We don’t want any disturbances, absolutely,” Eichhorst said. “Unfortunately, a lot of these places are very isolated, and if you put up a fence or anything around it, you just marked it. We mark that the GPS coordinates are a suspected grave site that’s been verified with cadaver dogs, and you know it’s there and the people that care know it’s there, but it’s not open to the general public for the risk of vandalism.”

Hurlburt said her dogs get called about a dozen times a year to seek out human remains and may be back in action again at the City of Rocks to identify more suspected grave sites.

“They have been utilizing dogs more for this type of deployment for numerous years now,” Hurlburt said. “It’s becoming more and more common.”

She said cadaver dogs have been used on historic battlegrounds such as the WWII site at Iwo Jima, Japan, and to detect graves of indigenous people.

Hurlburt’s dogs train at cemeteries and museums. They are certified with the North American Police Working Dog Association.

“Joe (her husband) and I help instruct at Texas State University, they have a forensic anthropology department,” she said. “Twice a year they bring in dog teams to allow them to work on a full body or just skeletal remains. They have some that are easily a couple of thousand years old that they’ve allowed us to work and train with the dogs. It’s really quite interesting. The dogs really don’t exhibit a difference. To them, it’s all human. It never ceases to amaze me what they can do and how smart they are.”