Sniffing Out History

It was a beautiful spring day when the collection of scientists and history buffs climbed a narrow pine-shrouded trail to crest a Bitterroot mountain ridge. In a sense they were chasing the past, for they hiked the famed Lolo Trail — the same route used by Lewis and Clark in 1805 and American Indians for millennia before that. Though barely discernible now, the trail was once one of western Montana’s major roadways.

The group was led by two tongue-lolling border collies named Rhea and Nessie. Their mission: sniff out the 150-year-old grave of the mountain man for whom the trail was named.

Local folklore suggested the grave of Lawrence Rence, a French-Canadian, was located atop a hill 16 miles west of the town of Lolo. He was nicknamed "Lolo" because Indian and English speakers of his time evidently struggled to pronounce Lawrence. Lolo, who had a Nez Perce wife, is believed to have been killed by a grizzly sometime in the 1850s or ’60s.

Local members of the Lewis and Clark Heritage Association wanted to erect a memorial to the historic mountain man, but first they wanted to ensure his grave was actually there. So, assisted by UM’s anthropology and geology departments, they tried a magnetometer survey, which was inconclusive, and ground-penetrating radar, which was blocked by clay soils. Then they decided to try dogs that have been specially trained to detect old graves.

The dogs’ handlers, Adela Morris and Eva Cecil, work for the Institute for Canine Forensics in Los Altos, Calif. Atop the ridge, Morris yelled, "Rhea, come!" and suddenly the smiling dogs were all business. For about half an hour their noses vacuumed the clearing where Lolo reportedly was buried. Several times they sat down - making an "alert" - and stared intently at their handlers. Then they rose and sniffed some more, pausing occasionally to drink out of their foldable water dishes. Detecting lost graves is evidently thirsty work.

So did their keen canine noses find anything? Kelly Dixon, the UM historical archaeologist who used UM Provost’s Office funding to bring the dogs to Montana, said the canines alerted downslope from a "hotspot" where the magnetometer had detected an underground anomaly that might be a body.

"I remember thinking it’s not exactly X marks the spot, but it’s a few meters away," Dixon says. "Of course, human remains, whether they are liquid or anything else, will migrate slightly downhill over the years because of gravity. The handlers, because of past experiences with this situation … felt like it was the ultimate success."

With the blessing of private landowner Paul Rosignol, Dixon’s team carefully sampled the soil at the suspected grave. They also took several control samples relatively far from the site for comparison.

Dixon says her graduate student Heidi Hill is conducting analysis of the soil for a master’s thesis. If there is something that human bodies leave behind in old graves that dogs can detect, Hill’s job is to find out what it is.

As for the Traveler’s Rest Chapter of LCHA, members were convinced that the dogs, magnetometer survey and local recollections had provided enough multiple lines of evidence to erect the Lolo memorial. The marker, which says Lolo had been laid to rest in the area, was installed this past summer.

After the Lolo search, UM anthropologist Ashley McKeown used the dogs at the former Missoula County Poorhouse Cemetery, located near Rattlesnake Middle School. The dogs were tired by then, but they made some hits near the school. McKeown says they don’t know yet whether the dogs discovered graves, but research is ongoing.

Nessie sits to make an "alert" for handler Eva Cecil at the Lolo grave site

Dixon says many of her scientific peers don’t accept forensic canine evidence, but she has been willing to study the dogs to determine whether their sense of smell can provide benefits to archaeology.

The 35-year-old assistant professor first tried using dogs in the field in 2004 while working on an excavation of the Donner Camp. The Donner Party, according to western lore, became trapped in California’s Sierra Nevada Mountains in 1846 and resorted to cannibalism to survive the harsh winter. Dixon’s research team is trying to determine whether the facts at the campsite corroborate the myth.

The Donner excavation garnered a lot of attention, and a private detective who wanted to be involved with the project suggested Dixon’s group try dogs trained to detect human remains. This led Dixon to the Institute for Canine Forensics.
She says the institute trains its dogs in different settings. One is an old NASA installation containing bunkers and housing for staff and trainees. It’s empty now, and institute employees set up crime scenes there using human remains and blood for the dogs to investigate. The dogs also train at the cemetery of an old poor farm that once contained an insane asylum.

She learned from her past work with Morris and Cecil that when the ground temperature becomes too hot, it dries out their dogs’ noses. So the canines seem to be most effective in spring or in early morning. Their handlers constantly monitor the ground temperature as they work.

Dixon says they didn’t immediately unleash the dogs at the historic Donner site. First they tried the canines in a nearby, known 1800s cemetery in which many of the gravestones had disappeared.

Kelly Dixon measures a soil sample

"Of course they alerted where there were grave markers," she says, "but then they walked where there were no grave markers, and the handlers placed a pin flag in the ground where they alerted. And when the dogs were done, we stood back and observed that the dogs had left a straight path of pin flags, reminiscent of cemetery rows. That was compelling."

At the Donner site in June 2004, several dogs independently alerted in the same area in a vast meadow. But when digging started a month later, archaeologists didn’t find anything in that spot. Dixon says it might mean somebody had died there and the body had long since been moved by scavengers or something else. But they took soil samples from the spot, and Hill’s thesis will study those as well.

Dixon said they tried the dogs again at the Donner site after the excavation had begun. This time one of the institute’s top dogs, Riley, alerted at the edge of a campfire hearth researchers had unearthed.

"We got lots of bone from that hearth," she says. Is it human? "It is a challenge to recover DNA because the bones are so tiny and burned to the point of near incineration. This may be the result of intense processing of the bones to garner as much nutrition as possible from them."

In addition to the ongoing DNA tests, Dixon says some bones will undergo osteon analysis — taking thin slices to analyze the cell structure.

The UM researcher believes dogs can smell the decomposition of humans, but the challenge is to ensure that their capabilities are associated with scientific validity. What, exactly are they smelling? What is different about areas where humans are buried?

Spectators watch as grave-detection dogs investigate Lolo's ridge-top resting place

"We discovered that we couldn’t just open up the Journal of Forensic Sciences and look at a paper that describes a human decomposition signature in the soil to compare our dog-alert soils with that data," she says. "This means we are literally starting from scratch with analyses of the soil samples from these sites."

Dixon says they were able to piggyback on the experiment of a former UM forensic student. The student buried a pig and some human rib bones to study their decomposition, and Hill, Dixon’s graduate student, collected soil from that burial site. The rib bones came from a donor collection.

"This represents an appropriately controlled experiment that can provide us with an opportunity to examine the differences between human and animal decomposition signatures in soils from the same site," she says.

Dixon’s team now is studying soil samples from the Donner and Lolo sites, and the Institute for Canine Forensics recently sent them soil to test from a 7,000-year-old burial in Europe where the dogs were used. Perhaps with further research, they can discover what the canines are detecting, and, as Dixon says, "put words in the dogs’ mouths."

If the dogs continue to prove themselves, Dixon sees them being added routinely to archaeology’s suite of remote sensing tools.

"Our goal is being able to conduct archaeology using this and other forms of non-destructive, noninvasive methods, creating a sort of X-ray vision into history."

For more information, e-mail Dixon at kelly.dixon@mso.umt.edu