Above ground noninvasive technique to locate human remains and historical graves: The nose knows

Adela Morris
Institute for Canine Forensics

Paper presented at the Society for Historical Archaeology Annual Conference
Sacramento, California
January 11 – 15, 2006

Institute for Canine Forensics
The Institute for Canine Forensics is a non-profit organization located in the San Francisco Bay Area of California. It was formed in 1998 to advance the field of Forensic Evidence and Human Remains detection dogs in both law enforcement and cultural resource management. The core group has been involved in human remains detection, working with law enforcement agencies and search and rescue teams for 15 to 30 years.
Detection dogs have a long history and proven record in locating modern day crime scenes and homicides, and in locating deceased humans. Many of the techniques used in teaching the dogs to locate modern day crime scenes and burials also apply to historical and prehistorical work. However, improvements and newer techniques have been developed to train dogs in locating the older graves.
The most significant advancement came through observation of the different techniques dogs use to locate scent. A dog trained to locate live people works with its nose in the air in order to catch the airborne particles of live human scent. Historical human remains detection dogs are taught to keep their nose near the ground to find the older human remains scent that is only present on the surface of the ground. However, many facts still remain a mystery in the detection of historical and prehistoric human remains.

Environmental Factors and Scent Theory
Studies are currently being conducted to determine what gases and chemical compounds are produced during the active stages of human decomposition. Dr. Vass et al., at the University of Tennessee’s Decomposition Facility and the Oak Ridge National Laboratory, has isolated over 400 compounds. Unfortunately, this research does not address historical or prehistoric graves and the chemical compounds that are present and can be detected.
To understand how historical and prehistoric graves hold scent, one has to rely on experience gained in working modern day homicides and clandestine graves, plus scent theories and guesswork. It is easy to conceptualize the amount of scent given off by a modern day victim of a homicide, even a victim that has been buried to hide the body. As the body decomposes, scent compounds escape and rise to the surface, making the scent available for detection by the dogs. As time passes and the active stages of decomposition diminish, less gas is produced, making older graves more difficult to locate.
Environmental conditions not only affect the rate of decomposition, but also the amount of scent available for the dogs to detect. Composition of the soil, as well as the depth of the burial, will dictate the amount of scent that escapes. Loose sandy soil and shallow burials promote the availability of scent whereas clay soil and deep burials hinder the release of scent.
The scent compounds travel away from the decomposing body or skeleton by way of diffusion, water movement, animal or insect activity, and plant or root activity. For example, rainwater infiltrates the ground and washes over the body, transporting the chemical compounds with the flow of water. Scent, like water, takes the path of least resistance and will flow downhill. As these combined molecules flow away from the burial, the scent travels with it. As the water molecules evaporate to the surface or flow to a new location, the scent is also moved to that location and released.
Burrowing animals, such as ground squirrels, as well as some insects, create channels in the soil that also promote the release of scent to the surface. The slope of the terrain and locations where the rodent holes open to the surface will move the scent.
Other environmental conditions that break down scent are sunlight, heat, and wind. As expected, intact, undisturbed graves have more scent available for the dogs than disturbed, scattered graves or bones that have been exposed on the surface.
Several different scenarios would contribute to the dogs’ level of interest and pattern of alerts at historical sites, with or without graves. If the bodies (or parts) were moved to different locations, snow and rain runoff would carry the decomposing scent to many additional locations. Bones and other remains might be moved by animal scavengers, and each new location would contain scent. Small bone fragments that had been scattered or buried, and remains that were charred, cooked, and then discarded in the cooking hearth, would all contain scent detectable by the human remains detection dogs and would leave a diffuse pattern.

How the Dogs are Trained
Historical Human Remains Detection dogs are imprinted and trained on the soils from human graves, human bones and teeth, artifacts related to graves, and on historical cemeteries. Grave soils tend to keep the “human signature” and can last in the soil for thousands of years, depending upon how well they are protected.
The imprinting scent is paired with positive rewards and experiences. Dogs repeat behaviors that are rewarded in a positive way and will avoid negative experiences. A solid foundation is very important to detections dogs. Starting with a young dog helps ensure you are molding the dog to be solely focused on a specific task. Dogs with minimal early training will develop their own agenda and habits, which may be counterproductive for detection work.
Detection dogs have been trained to give a specific trained response to the scents on which they have been imprinted. This response is called an “alert,” which usually takes the form of a “sit” or a “down.” Staying at the source of the scent ensures that the dog will not lose the scent location. Therefore, with training, a dog can search an area of interest and alert on locations containing human remains scents and provide vital information on historical archeological sites that may not be available using traditional methods.

Donner Party Alder Creek History
The Donner party split into two groups when George Donner was delayed because of a broken axle on his wagon. Time was critical, as it had already started to snow as they attempted to cross the Sierra Nevada Mountains near modern day Truckee, California. The 21 immigrants that stayed with George Donner soon became trapped and were doomed to spend the winter of 1846 – 1847 in their makeshift shelters at Alder Creek.
Only half survived. Of the eleven that died, three died trying to cross the mountains to get to safety, and eight died at Alder Creek.
The second relief party, lead by James F. Reed, arrived on March 1, 1847, and recorded that they found “hair, bones, skulls, and the fragments of half-consumed limbs” at Jacob Donner’s fireplace, and that outside they found “the snow-grave of Jacob Donner,” which contained his head and torso. The party also reported that other graves were seen, but that nothing remained in them but a few fragments of half-consumed limbs.
By March of 1847, Lewis Donner, Elizabeth Donner, and Samuel Donner had all died. Nothing is known about the burial of Elizabeth Donner, Jacob's wife. However, two different accounts are documented about George Donner’s body. One witness states that General S.W. Kearny’s party reached the Alder Creek camp on June 20, 1847, and that they found the body of George Donner, which was then buried by a party of men detailed for that purpose. Another member of that same party said that no burials were ordered at the Alder Creek camp. Journal accounts from the fourth rescue party (April 1847), state that “human bodies terribly mutilated, legs, arms and skulls, scattered in every direction” were found. Finally, no records have been found describing any burials of the remaining bodies or disarticulated remains after their snow-graves had melted.

Where Are the Remains?
Conflicting accounts exist regarding the burial of George Donner, and several descriptions of the camp describing the bodies being mutilated, disarticulated, and scattered in every direction have been documented. The remains of eight cannibalized bodies buried in the snow or left at the hearth would have easily been scattered by animal scavengers. The remains could have easily been dragged off long distances, or remained in place to decompose, and over time would be covered with plant growth and soil. The taphonomy of human remains dictates how the scent is preserved for the dogs to locate. If bones decompose with the soft tissues, as in a typical grave, the scent available to the dogs will be much more localized and stronger compared to bones that have been scattered after the tissue has decomposed or removed by carnivores.

Canine Search for Human Remains at Alder Creek
On May 28, 2004, the Institute for Canine Forensics (ICF) teams met archaeologists Kelly Dixon and Carrie Smith at the Alder Creek location. The date was chosen early in the year to take advantage of cooler temperatures and the moisture in the ground. The daytime weather consisted of overcast and cloudy skies, with temperatures in the mid-60s. The soil was moist from recent rains. Assignments were made to cover several locations.
It was important to search sites that were historically thought to be camp locations. Areas covered were the Donner stump, Donner tree, the open field behind the Donner tree, and the large meadow. The dogs started to show interest only when they got to the far southeast end of the open field, where in 2003 a bone fragment with cut marks had been located. The areas were double-checked by having a second dog work the same area.
The interest and alerts the dogs showed were inconsistent with behaviors seen when searching an organized, historical Christian-style cemetery, but were consistent with defused scent or scattered remains. Although the dogs did pinpoint several different locations, they did not have the pattern of commitment to exact locations as seen with whole, intact graves.

Returning to Alder Creek
On July 10-15, 2004, ICF returned to Alder Creek to re-work the dogs and observe the excavation of the site. This time, two additional dogs were added that had not worked the site previously. All the dogs indicated the same locations, but because of the heat and drier conditions, they had difficulty in getting scent during the heat of the day. Searches in the cooler morning hours were more effective. Ambient air temperature at 12:30 P.M. was 112°F. Not all alert locations were excavated, as this would have taken time away from the main area of interest to the archaeologists.
Of particular interest to the dogs was an area identified as the hearth. Soil samples were taken from the hearth at the time of excavation. In April 2005, two of the ICF dogs worked the hearth soil samples that had been brought to the University of Montana for analysis, and both dogs immediately alerted on the samples. Returning again to Alder Creek on July 13-14, 2005, one of the ICF dogs yielded consistent results by alerting in the same locations as those identified the previous year.

Conclusion and Opinions
More ground truthing is needed to clearly understand and confirm the dogs’ alerts on historical and prehistoric burial sites. The Alder Creek campsite is truly unique, and it is difficult (perhaps impossible) to find similar sites to compare the dogs’ reactions and alerts. We can only make educated guesses about what happened to the human remains and how the scent would be affected.

It would have been a great triumph if our dogs had located George Donner’s intact grave, but dog alert patterns, documented history, and bone evidence found while excavating the site do not support reports of the burial of George Donner.
The dogs were consistent in their alerts and interest at the same locations on all the dates we searched the site. Although their behavior was inconsistent with intact graves, it was consistent with scattered and exposed bones and diffused scents.

Experience shows that whole bodies in active stages of decomposition in shallow graves are the easiest for the dog to locate, with prehistoric graves being the most difficult.

The purpose in promoting the use of specialized historical human remains detection dogs to locate historical and prehistorical burials is to protect burials from unintentional excavation, locate burials for research purposes when appropriate, preserve burials for future generations, and to protect burial customs and provide respect to the dead.

Reference List

Bryant, Edwin "What I Saw in California" (1848) Lincoln: University of Nebraska Press, 1985, p. 263

Haglund, W.D., Reay, D.T., and Swindler, D.R., "Canid Scavenging / Disarticulation Sequence of Human Remains in the Pacific Northwest" Journal of Forensic Sciences, JFSCA, Vol.34 No. 3. May 1989, pp. 587-606

Johnson, Kristin "New Light on the Donner Party"
www.utahcrossroads.org/DonnerParty/Chronology.htm

Johnson, Kristin "Unfortunate Emigrants": narratives of the Donner Party, Utah State University Press, 1996

Johnston, J.M. (1999) "Canine Detection Capabilities: Operational Implications of Recent R & D Findings"
Institute for Biological Detection Systems, Auburn University

Jones, Nathaniel V. "Extracts from the Life Sketch of Nathaniel V. Jones by his wife Rebecca M. Jones." Utah Historical Quarterly 4, no. 1 (1931): 19.

Martin, Paul S., Sullivan, John
"The Science behind Voodoo Magic: Understanding the Human Decomposition Scent Spectrum & The Use of Cadaver Dogs to Locate Burials"

Thornton, Jessy Quinn. Oregon and California in 1848. (1849) In Kristin Johnson, ed. Unfortunate Emigrants: Narratives of the Donner Party (Logan: Utah State University Press, 1996), p. 91. Note: Thornton interviewed Reed in November-December 1847)

Vass, A Arpad, Smith, R.Rob, ET AL. "Decompositional Odor Analysis Database" Journal of Forensic Sciences, July 2004, Vol 49, No.4, available on line at: www.astm.org