Episode six: The scent
A dog's sense of smell is 10,000 times more powerful than our own.
Dogs are able to sniff continuously, exhaling through slits on the side of their nose.
They can determine which nostril the scent has come from, helping hone in on the direction of an odour.
And when they hit a trail, they can tell which direction the thing they're tracking was moving, based on the minuscule differences in the strength of the scent.
Dogs were domesticated around 15,000 years ago and human beings have making use of their incredible noses ever since.
They've been used for hunting and tracking, although nowadays, working dogs are more likely hunting for drugs or explosives.
Canine noses can also detect the smell of bacteria in beehives, abnormal blood sugar levels in diabetics, metastasizing cancer cells...
And then there are cadaver dogs, trained to detect the scent of human remains.
In episode six of SKS, handler Kim Cooper and her cadaver dogs Breeze and Grief continue their search of the area around Holmes Lake, where five-year-old Adrien McNaughton was last seen.
They are joined by highly trained volunteers, Pauline Sunman and her dog Quinn, as well as Susan Reid and her dog Zappa.
If Adrien died that day in June 1972, these four dogs might be able to find him.
These dogs and their powerful noses could help lead us closer to the truth.
Someone Knows Something is an episodic series, best listened to in order. Click here to catch up on any episodes that you may have missed.
Q&A with Kim Cooper, cadaver dog trainer and handler
Q - What's the difference between a search and rescue dog and a cadaver dog?
A - A search and rescue dog looks for live humans, though they can often successfully locate the recently deceased. Many are cross-trained to indicate items (clues) bearing human scent, such as clothing, wallets or water bottles. Cadaver dogs are specifically trained to find human remains, in all their stages of decomposition.
How long have cadaver dogs been in use?
Since the early 70's. The first cadaver dog program came out of England, followed closely by a program in the US.
In what sorts of situations are they generally used?
Cadaver dogs might be deployed when it is deemed that so much time has gone by since the initial disappearance that the missing person is unlikely to still be alive. Cadaver dogs might be used to search for drowning victims. They have been used to locate murder victims in shallow graves or even interred in basement foundations.
How often do you participate in these sorts of searches?
Ottawa Valley Search and Rescue Dog Association (OVSARDA) typically attends three to six searches a year.
What breeds make the best cadaver dogs?
Breed is not important, it is a dog's characteristics that define a good cadaver dog candidate. Dogs need to be very energetic and very motivated to work for a reward. Insatiable ball drive is a highly desirable trait. The dog needs to be of athletic build and in excellent health. Typical cadaver dog breeds might include German Shepherds, Malinois and Labrador Retrievers, but there are many dogs not of these breeds that could be excellent prospects.
Briefly describe the training process for the dogs.
Dogs might start their training as young as eight weeks of age, though some start later. First, the dog is imprinted on an odour by being exposed to it, which will be paired with food or toy rewards. As the odour of human decomposition literally changes on a daily basis, there are many different scent pictures that the dog must imprint. Once the dog values the odour and will eagerly seek it out, an indication is taught. Some dogs will sit or "down" when they locate a source. Others might be taught to "recall-refind."
What exactly do you use to teach them the odour of human decomposition?
The dogs are trained on true odour sources, which means real human remains. Mainly this consists of bones and tissue, very commonly placental tissue donated by new moms. Occasionally, we get access to the surface upon which a body has lain for several days before discovery, such as carpet or dirt, which will hold products of decomposition. We will train on a given odour source for approximately six months before disposal, making no effort to preserve it.
Are the dogs certified in some way?
Our dogs certify with the North American Police Work Dog Association. Certification testing involves obedience and search components. For the search components, the dog must search in six different contexts: woods, buildings, vehicles, rubble, buried and submerged. A total of 12 hides will be placed and the dog must correctly indicate a minimum of 11 in order to pass. Dogs are recertified annually.
What's the process (training, certification, etc.) for becoming a handler?
There are various certification standards under which one might qualify. In the Ottawa Valley, our handlers must be qualified annually by our provincial association in basic search and rescue skills: map and compass, search strategies, clue awareness, survival, etc. We all maintain first aid/CPR certification, and receive additional training in K9 first aid. In addition, as cadaver dog handlers, we must also qualify in HAZMAT, Bloodborne Pathogen Awareness, and Crime Scene Protection. By virtue of all the time we spend in the bush training, we are extremely proficient with GPS and radio.
Additional reading about the scent of human decomposition:
Chemical & Engineering News: April 4, 2016
Scientists search for death's aroma
"Just 15 mg of human tissue, blood, or bone can be enough to alert cadaver dogs to the location of a corpse, says Arpad A. Vass, a forensic anthropologist at the University of Tennessee's Law Enforcement Innovation Center. Although they aren't perfectly accurate, properly trained cadaver dogs can focus on human remains while ignoring the corpses of other dead animals nearby, a fact that's given scientists hope that they might identify a unique scent for decomposing human flesh—a human odor mortis, so to speak."