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Introduction
The way dogs experience the world differs from that of most humans in that olfaction replaces vision as the dominant modality of sensation. Knowing this, we have made and continue to make use of our four-legged friends' exceptional ability to perceive nonvisual cues in order to supplement our own sensory capabilities. In some cases, such as hunting, people rely on dogs' innate patterns of behavior to achieve the desired results. In other situations, however, such as in detection of odors, dog handlers use conditioning techniques to train their dogs to work alongside and communicate with them.
For example, police dogs detect odor traces or substances. When committing a crime, an offender comes into direct contact with his victim or with objects. Consequently, he often leaves traces (fingerprints, footprints, marks left by objects). Crime-scene investigators throughout the world today give increasing importance to the physical changes to a crime scene made by scent prints. They also analyze traces of substances found at a scene, on a victim, or on an offender. Scientific progress in recent decades has led to a reduction in the amount of odorous substance investigators require for successful analysis. This in turn has led to the possibility of carrying out analyses on microtraces (microscopic amounts of substances). A human smell is a particular type of microtrace.
Based on our experience with tracker dogs, we believe that an offender can be identified by the particular smells he leaves behind at the crime scene. Each person has a distinctive smell; this has been proven by experience as well as by experiments using various apparatus. Mass spectrography has also been used to analyze and identify human odors. The identification of offenders by analyzing traces of their odors has increased in importance as it has been scientifically proven that no two individuals smell alike.
All humans perspire. When it is hot, odor molecules from human perspiration disperse into the environment; this dispersal increases as the temperature increases. The human body seeks to maintain its average body temperature (98.6 F/37 C), and when it is hot, perspiring helps the body cool off. As well, when we experience fear, or undergo physical or emotional exertion, our body temperatures rise, which leads to increased perspiration and accompanying odor. We don't like to admit it, but we are sources of smells, and when we move about we leave behind odors. The entire human body emits smells. For example, when we walk across a room, odor molecules are released onto the floor and become attached to other objects we touch. Thus, despite any and all meticulous precautions he may take, an offender cannot avoid leaving traces of his specific smell at the scene of a crime. He can neither destroy secretions nor prevent them from forming.
Each dog's nose depends on its individual physical qualities, its training, and the frequency with which it is used. Even a dog with a natural talent for sniffing things out must be trained well in order to be able to identify odors correctly. Daily training, increasing in difficulty as the training period progresses, helps dogs develop conditioned reflexes. The sole aim of training a dog to identify odors is to teach him to make optimum use of his exceptional gifts in order to meet human needs.
A dog's ability to detect and, by inference, objectively identify odors depends on proper training techniques. If he doesn't regularly practice identifying smells under his handler's supervision, the dog will not be successful when he sets out to detect and identify odors. So, scent-detection dogs aren't ready for work unless they train regularly and systematically.
The dog's sex is an interesting factor when it comes to scent detection. It has long been known that females have a better sense of smell than males, so it might seem surprising that police dogs are almost exclusively males (hence the use of the masculine pronoun relative to dogs throughout this book). It seems that the presence of females, particularly when in heat, can upset males. In addition, a female's sense of smell decreases considerably when she is in heat, and her work is therefore not effective for a 16 to 24-day period every six months, and may even be affected weeks before and after this period. Most spayed (also called neutered or castrated) females, however, do not cause the same upset to males, nor do they experience periodic decreases in their sense of smell, and so their search work is consistent.
Training improves a dog's sensitivity to smells, enabling him to progressively detect fainter and fainter traces of odors. In this book, we have drawn up special training programs to this effect, and the overall effectiveness of the exercises has been demonstrated in practice. Drawing from our extensive experience in training our many service dogs the sorting, tracking, and detecting skills they need to find, for example, drugs or explosives, we have laid out here the specific exercises your dog needs to practice to become a scent-detection expert. In this book, we also tell you about the mistakes that can be made in different training programs, clearly justifying our method. Moreover, we insist that teaching a dog to track is the logical next step after teaching him how to sort odors.
And, of course, in this book you will find the necessary hints and tips that will help you help your dog learn. Following are the first three:
1. Identification: When sorting odors, always be aware of the so-called Clever Hans effect, by which a dog reacts to minimal and often unconscious changes in posture or other small movements made by you, the handler, or others present, as soon as he approaches the matching odor. (You can read more about this subject in our book K9 Fraud!)
2. Tracking: If your dog has lost the track, try to find it again by approaching where you think it might be at an angle of 90°. Your dog's behavior will tell you if you are back on track again: if he crosses the track, he will turn left or right and will follow the track again.
3. Detection: Although it is not pleasant, always take a close look at dog waste bags. Several times we have found drugs in such bags, casually placed next to other poop bags or near garbage bins.
Identifying the odors you present to your dog is not a natural activity for him, and so he must be specially trained to do so. A dog does not identify a human smell just because it is there. A scent-detection dog does this for his handler and for the reward he gets in return. A dog's attachment to his handler is therefore the foundation of scent-detection training and the work that follows. Always remember that your behavior and skills as a handler have a profound influence on your dog. His accomplishments are the result of the tight bond he has with you, his two-legged partner.
