The Right Dog for the Job

Saturday, May 15, 2021

Whether it is a missing child, a father who went hiking and never returned, or a brother suspected of having perished in a fire, those who seek CARDA’s help have one thing in common: a search for answers that will bring their loved ones home.

Training a dog for search work is not an overnight process. It takes time, patience, and commitment.

Handlers train all sorts of dog breeds for CARDA, with some of the most popular being German Shepherds, Labrador retrievers, and border collies.

Doberman Pinschers, Australian Shepherds, bloodhounds, and other herding or hunting dogs are also top choices.

CARDA does not have a protocol as to which breeds are allowed — the door is open to all, including mixed-breed dogs. This is because the breed is not what necessarily makes a good search dog. Rather, it is the drive that matters.

Good search dogs are typically high-drive dogs — motivated, tenacious, Type A-personality dogs who want to play the game, do the work, and get the reward.

They are active and energetic, ready to work the minute they step onto the field. They have great stamina, able to search for hours in a variety of climates and terrains. And they can maintain focus on the task at hand, unheeding of distractions.

These dogs want to work. They want to search and hunt. They just need to be trained on what to hunt for. Therefore, any breed can search, as long as the drive is there.

“They’re excited to work,” said CARDA volunteer Casey Rogers.

However, the general consensus is that toy or teacup dogs, such as chihuahuas, are not suitable for this kind of work. They typically lack the high speed, stamina, and drive required for search missions.

On the other extreme, very large dogs are also usually unsuitable, since their size can impede agility.

There is no exact “recipe” by which to train a cadaver dog. However, as with dog training in general, repetition and positive reinforcement are key.

Training begins when the dog is quite young, usually by the age of two years old. The handler may first place the human remains source somewhere simple, such as in a box, to pique the dog’s interest.

Then, after the dog alerts on the source, they receive a reward, such as food or a toy — whatever the dog wants. Over time, the scenarios become more and more complex as the dog is trained to find the source in more challenging situations.

Therefore, through consistent training, the dog learns which scent to focus on, and which scents to ignore, to get the reward.

“Everyone trains differently. But the overall basis is that you start by, like, putting out 10 boxes, and one has source in it,” said Rogers. “You start by teaching the dog that that’s the scent we want. That’s what we want you to look at.

“Then, we teach them how to tell us that it’s there — a sit, a come-back-and-find-us, whatever the individual handler chooses to do. And then we just expand from there, distance-wise, amount of source. It goes from in the box to somewhere in the room. And they have to start hunting.”

To avoid potentially disturbing the evidence, dogs are trained to alert by calmly sitting or lying down, nose pointed towards the source.

As for human remains training sources, placentas, blood, and teeth are the primary ones used due to their relative ease of obtainment. Dried, unbleached human bones can also be purchased from certain websites.

To familiarize dogs with every possible level of human decomposition, handlers often use the same sources for one to two years.

This allows the sources to age, and to capture a larger “spectrum” of human decay, as opposed to just a single “snapshot.” And of course, handlers must take care to keep their sources clean and uncontaminated.

Synthetic “corpse scents,” such as cadaverine and putrescine, are available for training use, but are not preferred. The gold standard is always actual body parts or tissue, because when it comes to human remains, nothing beats the real thing.

However, no matter how well-trained the dog, or how experienced the handler, the real world outside of training always presents challenges.

One of the biggest difficulties in searching for human remains is verifying the validity of a find. During training, the handler knows exactly where the source is, and can immediately confirm a dog’s find. But out in the field, this is no longer the case.

A dog’s nose is extremely powerful, and can detect tiny sources invisible to the human eye. For example, when a cadaver dog alerts to a find, such as a drop of blood in the dirt, a handler may see nothing.

Therefore, determining whether something of interest is actually present is a major challenge in human remains detection missions. Further analysis via technology may be required in such instances.

Indoor environments also pose challenges in accurately determining the location of human remains. In the outdoors, airflow is largely predictable and reliable, aside from some exceptional situations. In a building, though, ventilation systems such as fans and air conditioning can tamper with the airflow, spreading the scent around and throwing the dogs off their path.

“In a dormitory situation, for example, let’s say it’s five stories high,” said Rogers. “The deceased person could be on level three, and the dogs are picking it up on five because it’s going through the AC system. We did a search once where law enforcement decided to turn on the fans to clean out the smell in the room.

“You’re pushing the scent to where the body actually isn’t. And that’s when we as handlers have to backtrack to where the body could be.”

Ventilation systems should therefore be turned off while conducting indoor human remains detection searches, to allow the scent to settle and the dogs to pick up on the smell.

Water cadaver (C4) certification is a whole other specialty within CARDA that comes with its own unique hurdles. After becoming land cadaver-certified, a dog can also become water cadaver-certified, or trained to detect submerged human remains, such as drowning victims. Working on boats and along bodies of water, these dogs alert to the smell of human remains that rises up from under the water as the body produces gases.

The dogs already know the scent to focus on, and the physics of how scent travels does not differ much with water.

Like air, water distributes smell via currents, and the more water moves, the faster scent travels. But training for water cadaver certification presents logistic challenges. For example, situating human remains sources into bodies of water for training is difficult. And oftentimes, trainers must get creative with their methods.

One approach involves placing source into waterproof jars, tying them onto a pier, and then having the dogs attempt to detect from a boat.

In another newer method, divers enter the water with the cadaver scent on their persons. Once the dog alerts on the source, the divers surface with the dog’s reward, such as a toy.

Regardless, water is still a very tough discipline. In California, this is compounded by the fact that most bodies of water used for training contain blue-green algae, which is incredibly toxic for dogs. Thus, within CARDA, there are only six water-certified teams, out of over 300 members total.

Disaster situations, such as avalanches, earthquakes, and fires, are other scenarios in which cadaver dogs are deployed to search for victims. For earthquakes, agility is crucial, as the dogs must be able to enter the wreckage safely. Consequently, they are trained on rubble or tall concrete piles for these situations.

Such training facilities are hard to come by, but resourceful teams can find a way.

Some CARDA teams, for instance, attend an annual training day in San Luis Obispo called “Locating the Dead,” which offers full-body cadavers and rubble piles in their practice scenarios. Other teams use abandoned office buildings in Oakland, cordoning off each floor to a specific type of disaster training.

For fires, the principles are still largely the same as with human remains detection on undamaged property. Charred remains still emit the decomposition scent needed for detection.

Therefore, dogs are trained on cremains for fire scenarios, with each training source containing different amounts of bone. And surprisingly, the dogs do not frequently incur injuries while on fire jobs, considering the amount of destruction left behind.

“Amazingly, in a fire situation — and we’ve been in several of them — the only time my dog ever got hurt was after it rained,” said Rogers. “And speaking with most handlers, that’s when all the dogs got hurt. So there is something about the way they walk. They didn’t get hurt from the broken glass, the metal, the roof shingles, any of that, until it rained.”

Mudslides are more problematic. Because the mud often contains human waste, there is far more decomposition scent in the area. This makes it harder for the dogs to locate actual human remains, as it is more difficult to discriminate between scents. The mud also obscures visibility, making it challenging for handlers to verify finds.

In the long run, scent training is the most critical skill for cadaver dogs, and search dogs in general, to master. However, a search dog must also grasp other skills to participate in this line of work. Among them is basic obedience.

All CARDA search dogs must be able to heed voice commands for behaviors such as “sit,” “lie down,” and “long-down,” meaning to stay down for 10 minutes with the handler out of sight.

Another important cue is “stop on recall,” meaning that the dog is down, the handler calls them over, and then halfway over, the dog stops instantly on command for safety. This ability to follow verbal instructions must be spot-on.

Additionally, the dogs must be well-socialized and able to stay calm and undistracted around other animals or people. On the way to and from missions, they need to be able to stay in the car as told. Other necessary skills include agility and swimming, so that they can safely maneuver across terrains and through rubble.

However, the dog is not the only team member who matters. In CARDA, handlers must also master certain skills to effectively work alongside their dogs. Some of these include basic survival, such as CPR, Emergency Medical Response, and Wilderness First Aid.

They must know how to proficiently use a map, compass, and GPS to draw logical conclusions about source location, especially on trailing missions.
“Man-tracking” — another important asset for handlers to learn — involves visually assessing disturbances, such as crushed grass, footprints, and tracks, to determine where a person went.

“So what could happen is, we could be walking along, walking along, and then all of a sudden, I see a set of footprints where there shouldn’t be footprints,” said Portje. “And if my dog is following them, then I realize we just found the subject’s footprints. Now we have a last confirmed known location, which changes the search.

“So, [man-tracking] teaches us to be aware of our surroundings and how to find little clues that most people don’t notice.”

Read out about the inner life of CARDA volunteers next week’s in the final article of the series.