Slider and handler Sallee Burns
On incidents where search and rescue (SAR) dogs are called in to support wilderness search operations, members of the primary agency on the incident are often assigned to work on canine field teams. For a SAR dog team to work most effectively, it is important that the personnel assigned to the dog team have a basic awareness of SAR dog operations and be familiar with the responsibilities and possible functions of SAR dog team members. Dogs in base camp also present a unique situation for many non-canine SAR teams.
A basic understanding of scent theory is necessary to understand how a wilderness (lost person) search and rescue dog works. The origin of human scent that a dog smells resides in scent particles that a person is constantly shedding. These particles are composed of flakes of dead skin cells combined with body oils, sweat, and environmental odors.
Tens of thousands of these flakes slough off a person each second. Some of these flakes are very small and light, and are carried off on air currents. Other flakes are larger and heavier, and fall to the ground. The wind may carry some of these heavier particles up to several feet from the subject as they walk, creating a band of scent particles on the downwind side of the subject's path.
Hair is also shed and gives off scent. The chemistry of these flakes and hair reflect the person's genetic, dietary, and environmental conditions, making the associated scent as unique as a fingerprint. A dog is able to distinguish the scent of one person from that of another. If a person remains in one location for very long, there is a concentration of scent particles around them, forming a scent pool. Convection currents and wind carry the scent particles away from the scent pool. A secondary scent pool is formed when particles are carried by air currents and settle into a low lying area away from the person.
Wind, convection currents, terrain, and vegetation play major roles in the dispersion of scent particles and the characteristics of the pattern of scent that SAR dogs will detect. Bacteria also reside on the scent particles and decompose the scent particles. Bacterial decomposition converts a scent particle into gasses and other by-products, which continually reduces the size of the particle until it is gone.
The bacterial decomposition rate and, therefore, the length of time that a scent particle is converted to gasses, depend on the particle's temperature and moisture content. Temperature and moisture levels fluctuate through the day, between day and night, and from day to day. The size of the scent particle and the rate of bacterial action on it determine how long the scent particle will give off gasses, esters, and other decomposition by-products and how long a dog will be able to detect the unique smell of the particle.
The length of time that undisturbed scent may be detected ranges from several hours to several days, depending on the environmental factors effecting decomposition rate. Many events can disturb or destroy the scent particles, including rain, wind, and the passage of people, animals, and vehicles.
Search and rescue dogs detect scent that is either from light particles carried from the subject’s scent pool on air currents (air scenting) or given off by heavier particles that have fallen to the ground (trailing) during the subject’s passage through the area. Wilderness SAR dogs are certified in either air scenting or trailing, though many dogs are functional in both and some dogs are certified in both disciplines. Some SAR dogs are also certified as cadaver, disaster, and/or water search dogs.
In a lost person incident, dog teams are deployed with the intention of either air scenting or trailing, and are worked differently, depending upon their type of assignment (air scenting or trailing). Air scenting dogs work off leash and alert on scent from airborne particles. If possible, the handler will begin in the downwind portion of the assigned search area and work the dog in a systematic pattern that will allow the area to be covered as completely as possible.
The air scenting dog frequently ranges out of sight of the handler. The pattern of alerts of teams of air scent dogs, considered in the context of the atmospheric, vegetation, terrain, and wind conditions, provide information on possible areas where the search subject may be located. An air scent dog may also follow the stream of scent particles (called the scent cone) carried on the wind from the scent pool directly in to the search subject.
Trailing dogs typically work on a long (20 to 40 foot) leash and follow the scent given off by scent particles on the ground, much like a print tracking team. After they pick up the subject’s ground scent, they usually don't smell every step, but sample the scent in the air above the ground as they trot along. Some dogs alert on any human scent that they encounter in an area (other than members of the canine field team). Scent discriminating dogs have been trained to alert on or follow only a specific scent that has been presented to them through an article (called the scent article) containing the scent of the search subject.
When working an incident that includes search dogs, use common sense, both in base camp and the field, to avoid safety problems and misunderstandings that could develop from inappropriate actions. Never feed a search dog anything unless requested by the handler.
Dogs vary in temperament. In base camp, request permission from the handler before approaching a dog to pet it or play with it. On a field assignment, don't distract, pet, or play with a dog unless requested by the handler, and don't call out or talk to a dog unless its safety is in immediate jeopardy.
Before deploying, ask the handler how to respond if the dog approaches you while it is searching. In the field, dog team members may be asked to help lift the dog over a fence, and after an assignment, the handler may ask team members to hide for or play with the dog. Those who are not comfortable around dogs should request that Operations assign them to a non-canine team.
Prior to beginning an assignment with a canine field team, ask the handler for any special instructions or requests. The dog handler should be made aware of any known safety hazards in the assigned area, particularly for air scent dogs, who will be working away from their handler. Also, prior to deployment, inquire if it is all right to call out to the search subject if that is a viable tactic on the search to attract the subject's attention. Some search dogs may be distracted by people near them shouting.
Dogs that follow or alert on a specific scent will be given an item, called a scent article, to smell containing the search subject's scent. It is important that the scent article be as free of contaminating scents as possible, particularly the scent of a person other than the search subject, such as a family member, who may be in the search area.
Prior to dog teams arriving, the first SAR group on scene should isolate potential scent articles (as well as prints and other possible clues) from sources of contamination and destruction. If feasible, a dog handler should secure the scent article and place it in a sealed bag. Techniques for securing scent articles should be included in joint trainings with SAR dog groups. Persons involved in securing and transporting the scent article need to be as careful as possible to limit the contamination of the scent article and the bag it is placed in. A SAR dog is usually scented on the article only once, then the scent article is resealed in the bag.
On a field assignment with a dog team, support personnel should ask the handler where to walk with respect to the handler and dog. Most handlers will want the other team members to walk behind them. If the dog is on a leash, other members of the team should stay at least a leash and a half distance from the handler, so they don’t get tangled in the leash should the dog swing around.
Like prints, scent is also fragile and effected by the passage of people, vehicles, and animals through the area. Because of the possibility of more than one dog team working the same trace of scent, it is important that teams disturb the scent as little as possible in performing their assignments. Ground scent particles are often carried by the wind to one side of the path that the subject walked. When operating with a trailing dog following ground scent, observe how the dog is working and then stay on the opposite side of the trail, being careful to also avoid any relevant prints or other clues.
If in doubt, ask the dog handler for suggestions on how to avoid disturbing the scent that the dog is working. Air scenting dogs work from scent that is carried on air currents and which is usually being continuously replenished by scent particles from the scent pool around the subject. Sometimes, though, a dog will alert in a secondary scent pool. It is important to minimize the disturbance of these scent pools, because another dog may be sent to verify the alert of the first dog.
Most dog handlers, particularly those working trailing dogs, will focus their attention on reading the dog's body language for indications of the dog’s interest in specific areas. Other members of the team should be looking for hazards in the area and inform the dog handler if any are seen.
It will also be the job of the other members of the team to act as navigator, recorder, and, possibly, communicator. Trailing dogs follow close to the subject’s path, where there may be relevant clues. Canine field team members should look for prints and other clues that might be related to the subject's passage through the area.
If potentially relevant clues are found, they should be noted, flagged, and the information shared with all team members, including the dog handler. If the dog shows interest in a particular area, the handler may request a team member to note the location, flag it, and check the area for additional clues while the handler and dog continues ahead.
Remember that you are working as a team - the dog's skills and the print tracker's skills should both be used by the field team to detect clues related to the subject's passage through the area. Ideally, the team will move at the pace of the dog, but relevant clues, such as print fragments and other environmental disturbances, should be noted, called in to Operations, and marked for additional follow-up, perhaps later, by a print tracking team. Members of an air scent dog team may be requested to flag the perimeter of the search area or mark it on a map.
In addition to the normal contents of our field response packs, a dog handler will also pack food, extra water, and other gear for their dog. Because of the additional weight carried by the dog handler, the other team members should expect to carry the team equipment, such as, a medical trauma pack and mountaineering gear.
Some handlers create a leash out of tubular webbing. In field use, this leash is quickly abraded and worn, including being chewed on by the dog. The leash should not be used for any component of a rappelling system, including as part of an anchor system or as an improvised rappelling harness.
The most effective way to learn to efficiently work an incident with a SAR dog team is to participate in trainings with a dog group. SAR groups that use dogs from outside agencies should schedule joint trainings with the dog groups that they expect to call in on their incidents. In addition to familiarizing print tracking SAR personnel with dog operations and the dog/handler teams that they will be working with, the joint trainings should also include discussions and demonstrations on isolating and protecting scent articles.