Institute for Canine Forensics
The Society for Historical Archaeology Annual Conference
Sacramento, California, January 11-15, 2006
Canine training as an adjunct to fields such as archaeology and anthropology has advanced significantly over the past few years. Canines trained to locate human remains can be subdivided into three broad disciplines: cadaver dogs, human remain detection dogs, and historical human remains detection dogs. Although there are significant overlaps in the skills necessary for certification in these three disciplines, there are also distinct differences.
Cadaver dogs are usually called upon to locate recently deceased individuals in missing person and law enforcement cases. Human remains detection dogs are more likely to be employed to locate human remains related evidence at a crime scene.
Historical human remains dogs are specially trained to locate very old human remains, and are most likely to be employed by archaeologists to locate old burials.
Historical Human Remains, Human Remains Detection, Cadaver, Dog, Search, Canine, Burial.
There are three different types of working canines that find human remains: historical human detection, human remains detection, and cadaver. Significant differences exist in the training, testing, and usage of dogs working in these disciplines. Consistent terms and definitions are important to clearly distinguish the difference between these disciplines.
Historical human remains detection dogs are used to locate human remains that range in age from recently skeletonized to prehistoric.
Human remains detection dogs are used to locate human remains that range in age from recently deceased through all stages of decomposition, including disarticulated and skeletal remains. These dogs are typically employed by law enforcement agencies at crime scenes. They are able to locate trace evidence, blood splatters, and residual scent.
Cadaver dogs are used to locate recently deceased human remains, whole bodies and recently disarticulated bodies on the surface of the ground or hanging above ground. These dogs are also frequently training to locate live subjects.
Training detection dogs usually begins when they are still puppies, at about 6-8 weeks old. The puppy is introduced to the desired scent source in an open area with no distractions. When the puppy looks at or sniffs the source a reward is given. It only takes a few training sessions for the puppy to understand what their new job is. Training sessions are short, but may be repeated three to four times a day. As the puppy matures and learns the scent work, longer and more difficult training problems will commence. For historical work dogs are trained to do a passive alert behavior, usually a sit or down. The dogs are rewarded using food, a favorite toy, or praise from the handler. As the dog continues to advance in their training, multiple scent sources are used in a single training session.
The types of scent sources and their location vary depending on the discipline the dog is being trained for. Dogs being trained to do cadaver work are trained using fresh scent sources including: blood, hair, bone, teeth with residual blood and tissue, and body fluids. The scent sources are located at or above ground level. Human remains detection dogs are trained using scent sources in all stages of decomposition. The scent sources are located above and below ground. Training scenarios emphasize crime scene situations. These dogs are not trained on live human scent or on articles with fresh live human scent. Historical human remains detection canines are trained using older scent sources including: dry old bones, teeth with no blood or tissue remaining, artifacts, old grave dirt, and coffin wood.
Prior to being deployed on actual searches, each discipline must pass a unique set of certification tests. The State of California has developed a certification standard for cadaver dogs. Other states also have developed standards at a state and local levels.
The Institute for Canine Forensics has developed certification standards that address the unique requirements for human remains detection dogs and for dogs focused on historical human remains.
The field techniques used by each of the three disciplines are also very different. The primary use of historical remains detection dogs is to locate old burial sites. The dogs may be called in to assist with an ongoing archeological research project, to locate burials prior to excavation or construction, or to determine the boundaries of old cemeteries. Historical searches are slow, methodical, and time consuming. Typically a search area is divided into small sections that a handler and dog can work under an hour. Several teams independently search each section, with an observer recording the locations indicated by the dogs. Multiple dogs independently indicating the same location provides extra assurance of accurate results. In cemeteries, placing flags at each location identified by the dogs will often reveal a pattern of rows, which can be documented, photographed, and mapped for future reference.
Human remains detection searches are frequently preformed at crime scenes, which can be in wilderness areas, buildings, vehicles, ponds, rivers, and lakes. The human remains evidence may be buried below ground, on the surface, or even above ground level. These searches are often preformed in conjunction with the execution of a search warrant. The warrant may have specific limitations that must be observed by the team. In other cases, the search is in a public area, but needs to be conducted discreetly in order to avoid alerting potential suspects. Many of these searches are initiated on information gathered during the investigation or passed on by informants. It is common to find no trace of human remains at a search location.
Cadaver searches are usually related to a specific missing person. The missing subject may still be alive or they may be recently deceased. The body may be on the surface or may be above ground. These searches typically require the dog team to cover large areas rapidly. It is not uncommon to be requested repeatedly for the same subject, as new information can clues are gathered.
Hazards and Their Solutions
There are conditions that can make the dog’s work difficult or even hazardous. It is important that the requesting organization be aware of these conditions so that they can be identified in advance, communicated to the handlers, and where possible, plans made to mitigate the unfavorable conditions. The difficult and hazardous conditions are similar for all three disciplines.
Extreme heat or cold, will limit the amount of time the dog can work between rest breaks to as little as a few minutes. Both air temperature and ground temperature need to be considered. Remember the dog’s nose is working at ground level. Often the hottest parts of the day can be avoided; the dogs can work early in the morning, and in the late afternoon and evening. In some cases it may be feasible to reschedule the search for cooler weather, or even for a cooler season.
Soil conditions also play a significant role in the quantity of scent that escapes the ground. Hard baked clay soil is almost impossible to work in any weather, however, watering and probing or drilling may help this situation. Likewise west sticky clay also tends to be less permeable to scent. Probing and drilling may help.
The foxtail is a type of grass with seedpods that have a sharp point and stiff bristles on the back end. Foxtails may enter a dog’s nose or pierce their skin. Once a seed is embedded, the bristles cause it to work deeper and deeper into the dog and the sharp point can continue to penetrate soft tissue. Few handlers will work their dogs in the presence of foxtails, as the result is often expensive veterinary work. Foxtail penetration is occasionally fatal.
Thorns, thick brush, barbed wire, bees, berry bushes, poisons, loose dogs, and traffic are all hazards that may be potential problems.
Requesting Organizations and Their Expectations
It is important that an organization that is requesting canine resources clearly communicate their expectations with the dog handlers. In all cases the organization should expect the responding dogs have been trained not to damage any exposed artifacts or bones, and not to dig or disturb gravesites.
The organizations that request historical human remains dogs include archeologists, cultural resource management firms, native American groups, churches, genealogy groups, and historians. Each of these groups may have different types of projects, specific requirements that are unique to the organization or project.
Typically law enforcement agencies request human remains detection dogs for crime scenes and unattended deaths. Their expectations are that the dog is trained to preserve evidence. Furthermore they expect the handler to be familiar with crime scene protocols, evidentiary procedures, and court testimony.
With a clear understanding of the different disciplines of dogs used to locate human remains, organizations that are considering utilizing dogs to assist with the location of historical human remains should be able to differentiate available canine resources. The organization must also communicate their needs and expectations early in the planning process. Finally the organization must recognize the unique conditions that may pose problems for the dogs, and communicate these situations early in the process. With these things in mind, it should be possible for organizations to make good use of this exciting new resource.