Germany shocked the law enforcement world in 2010 with an ingenious idea: Why not use turkey vultures to search for dead bodies in murder investigations? Turkey vultures hunt with their sense of smell and scientists say they’re the best sniffers among the raptors. They’re naturally attracted to carrion. They can detect a dead mouse from a mile away and aren’t hindered by rough terrain. Could they be trained to distinguish human from animal bodies, be fitted with GPS devices, and help law enforcement solve cases?
As great as the idea was, it met its demise in the sharp talons of the vulture’s biology. Vultures aren’t sociable. They’re all beaks and claws. They use projectile vomiting to defend themselves, spewing the rancid, corrosive mess up to ten feet. The German researchers couldn’t get them to cooperate and the project was quickly abandoned.
Should Germany have looked at ravens instead?
It’s not that vultures can’t be useful on cadaver searches. Cadaver dog handler Cat Warren admits to keeping an eye on turkey vulture kettles during her searches. But other wild birds offer clues, too. Hanns Gross, the Austrian father of criminology, kept his eye on European vultures and kites, but also on a different carrion-eating genus: the corvids. Ravens and crows. Here’s an example from his 19th century handbook on criminology:
“The body of a murdered woman was once found in the following way: The teachers of the surrounding schools told the children to let them know if they noticed a flock of many crows, ravens, etc., anywhere; some of them made such a report, with the successful result that the murdered person was found.”
I say the Germans were experimenting with the wrong bird species. Shall we take a closer look at the raven?
Ravens are sociable and super smart
Scientists consider corvids the most intelligent birds. They’ve even documented corvids using tools. They’re trainable. A big plus is that they’re affable to humans.
It’s no accident that the raven plays such a prominent role in Norse and American Indian mythology. Ornithologist Bernd Heinrich devotes three chapters in his book, Mind of the Raven, to the raven’s cooperation with other hunters: wolves, polar bears, cats, and humans. There are anecdotes of ravens spotting prey and leading predators to it. Ravens probably learned that large prey, in combination with a hunter, translated into food. As a reward, the ravens got a chance at the leftovers.
In fact, man’s first best friend might not have been the dog. It could have been the raven.
A corvid, canine, and homo sapiens hunting triad?
It may not be an accident, either, that the Norse god Odin took two ravens and two wolves with him on the hunt.
In order to track down the bases for raven mythology, modern anecdotes of interspecies hunting cooperation, and rumors that Eskimo hunters “talk” to ravens, Bernd Heinrich traveled to Inuit villages on the Canadian tundra. He found ravens everywhere, often in close association with the Eskimo dogs.
The Inuit told stories of hunters’ ability to communicate with overflying ravens in bygone times. They used incantations and called out the raven’s name, “tulugaq!” Ravens, they said, indicated the direction of the prey by wing tipping. “And after [the hunters] killed the caribou or the polar bear,” said one elderly Inuit, “they always left the raven the choicest tidbits of meat as a reward.” It wasn’t always the faithful dog, then, that accompanied the ancient hunter. The raven may have been there too.
Where they don’t have humans to help them, ravens are just as happy to work with canines. Research from Yellowstone National Park indicates that ravens are dependent on wolves to kill and open carcasses for them. Heinrich says that points to a relationship with an ancient evolutionary history.
Given that ravens also eat carrion and can spot it from the air, could they be trained to search for human bodies and work in cooperation with cadaver dogs and their handlers? Humans and canines are, after all, two of the raven’s traditional partners.
It’s an idea worth exploring. And it’s a more pleasant one than working with vultures.
Literature on point:
Cat Warren, What the Dog Knows: Scent, Science, and the Amazing Ways Dogs Perceive the World (New York: Simon & Schuster, 2013)
Bernd Heinrich: Mind of the Raven: Investigations and Adventures with Wolf-Birds (New York, Harper Collins, 1999). The quote appears on p. 252 of the Harper Perennial paperback edition.
Hanns Gross, Handbuch für Untersuchungsrichter (3rd ed., Graz: Leuschner & Lubensky’s 1899) p.124.Read More
Interview with Author and Cadaver Dog Handler Cat Warren
CAT WARREN is a professor and former journalist with a somewhat unorthodox hobby: she works with cadaver dogs—dogs who search for missing and presumed-dead people. What started as a way to harness the energies of her unruly, smart, German shepherd puppy, Solo, soon became a passion for them both (though Solo thinks it’s simply a great game, with the reward of a toy at the end). They searched for the missing throughout North Carolina for eight years. Cat is the author of What the Dog Knows: Scent, Science, and the Amazing Ways Dogs Perceive the World. You can visit her website at What the Dog Knows.
Ann Marie: Most cadaver dog handlers work on a volunteer basis. Why is that?
Cat Warren: It’s mostly about budgets. The fact is, cadaver dogs aren’t needed every day in the same way a patrol dog is needed every day. One of the founders of the field, Andy Rebmann, started the first cadaver dog program in the late 1970s with the Connecticut State Police. That program has survived up through the present. Other programs spun off from Andy’s founder effect—Rhode Island, Massachusetts, New Hampshire, Vermont, Maine. And a couple of large cities, New York and Chicago, have cadaver dogs and handlers. There are a few larger departments in the United States that still have cadaver dog and handler teams, and some small ones scattered across the country, especially sheriff departments, partly because their work can tend to be more rural. But increasingly, law enforcement depends on volunteers for this function. A good volunteer dog-and-handler team can produce some excellent results.
Let’s get the big question out of the way first. I can imagine that the biggest objection most people would have to cadaver searching is the shock and horror of finding a dead body. What would you tell them?
I have a harder time watching a show like Bones or any Hollywood version of death and decay than I do looking at a dead body out in nature. I think we media-saturated Westerners are now hardwired to replay all the worst possible film and television scenarios in our heads. But decomposition, even human decomposition, is usually a quieter phenomenon. The human violence or tragedy that brought the victim to that spot is past, and I have trained myself not to focus on that, especially when we are searching. It’s important that the dog have a good time; that’s how they do their best work: in happy mode. Any dread the handler feels, as trainers note, goes right down the leash. It’s the handler’s job to let the dog do his best work. Besides, for me and — I expect, for the majority of searchers — finding the person who is missing and dead represents success. Absolutely, it’s sad that someone has died, but it’s not a surprise. We usually know going out to search that the outcome probably won’t be finding someone alive. Finding the victim is the beginning of a resolution for those who knew the person, and for law enforcement. I do understand it when people think I must do this work as a dutiful public service. No. It’s a challenging puzzle, it pushes dogs and handlers to their mental and physical and scent limits. Plus, I get outside, often in the woods, and I get to watch dogs use their noses — one of the most pleasurable sights on earth.
What are the qualities that make a good cadaver dog?
The same qualities that make any good scent detection dog make a good cadaver dog. Good cadaver dogs love to hunt. They have what trainers and handlers call “drive,” which is a complicated and often misunderstood term. To oversimplify, a dog with drive has a lot of engine underneath its hood, even if it doesn’t have that engine revved in every situation. Often, with scent detection dogs, trainers look for dogs who are toy- or ball-obsessed because that obsession can be transferred over to the hunt for the particular scent the dog is being trained to find.
A good cadaver dog needs to have a good nose, an ability to focus, the desire to work long and hard for a reward, and be in good physical, and mental condition. Good cadaver dogs need to be both deeply bonded to their handlers, but also be independent and able to make decisions on their own. It’s a strange combination when you think about it — but you want dogs that are experts, in a way. You want to work with a dog that says, “let’s go this way, not that way.” And finally, a good cadaver dog is trained on a spectrum of human decomposition scent: from teeth and old bone up to material that is much fresher.
And a good handler?
Ah, I wish I were capable of doing all the things that make a good handler. Then I would be a better one. It takes an enormous amount of talent, time, dedication, imagination — and patience! When I watch good handlers work, here is what I see: They have great timing, so that they are rewarding their dogs at the exact moment necessary. Too soon or too late on the reward, and the dog doesn’t understand what it just did correctly. Good handlers are able to push their dogs by challenging them to learn more and do better, but not so much that their dogs lose their sense of security. In other words, it’s a delicate balance to create independence and expertise in dogs without throwing too much at them. But good handlers are always setting up increasingly difficult puzzles in training. Good handlers get out of the way of their well-trained dogs and let them work without interference. They set the dog up for success on searches. That means paying a great deal of attention to terrain and weather conditions, and what else is out in the environment. When I see good handlers work with their dogs, the process looks effortless and easy. Of course, it’s not.
How do you train a dog for cadaver searches?
That’s such an interesting question — and a complicated one. You train them both to be environmentally “hard” that is, to ignore and work past distractions, such as weird surfaces, rubble, fallen trees, the scent of other animals, traffic (cars and people). You also train them to recognize the whole spectrum of human decomposition. Bombs, drugs, and landmines are chemically simple in comparison to human decomposition. Yet, we do know that solidly trained dogs can tell the difference between deceased human, a dead deer, or aged goat cheese. But it’s not straightforward. Forensic anthropologist and research chemist Arpad Vass and his colleagues have identified nearly 480 different volatile compounds coming off of decomposing bodies. It’s just a start. He thinks it will be closer to 1,000 organic compounds, though not all of them volatiles, by the time they are finished creating a DOA database — which stands for Decomposition Odor Analysis, not Dead on Arrival.
Where do you obtain the scent for training?
It depends on what state or country you live in, and what the regulations are for that state or country. It’s really important to know the laws, exactly, before you obtain scent. For some countries, you can only use what we call “pseudoscent,” which is a company’s effort to get as chemically close to the scent of human decomposition as possible. Having diverse materials to train on is ideal, and “decomp,” as it’s called, comes in all varieties, from bone and teeth, to recent blood, to dirt that is harvested from beneath a body that has spent a good amount of time in the woods before being found. Dogs also need to be exposed to what they might find out on a search — a whole body. It can be confusing and even intimidating to some dogs, who are not trained on a daily basis with that much scent. We are fortunate in North Carolina to have a forensic anthropology research facility that helps train cadaver dogs on a small research plot where donated bodies decompose. That facility helps train forensic anthropologists — and cadaver dogs and handlers.
Even if a dog owner isn’t sure about training a dog for cadaver searches, what are some other scent games an owner can play with a dog?
There are so many things that one can do these days with dogs and their noses, from work to sport to just playing in the yard and house. Besides cadaver dog work, there’s conservation dog work — helping count and find either invasive or endangered species. There’s search and rescue for finding live victims. But many dog owners are finding their dogs love to do canine nose work. It’s a relatively recent sport, just like agility, only using many dogs’ inherent love of sniffing to get them engaged and confident. And I love to do simple games when it’s hard to get the dogs outside. Hiding a particular toy in the house and asking the dogs to go find that toy (and not the others) is great mental stimulation for the dogs. They work together, and get enormously competitive and interested in being the first one to find the hidden toy.
Whom should a dog owner contact if he or she wants to find out more about the possibility of cadaver search training?
It depends on where they live — the first step is to contact their area search and rescue groups, to see what they are doing. In the United States, we have several national groups that are a good place to start: the American Rescue Dog Association, the National Search Dog Alliance, or The North American Police Work Dog Association, which allows non-law enforcement handlers to be associate members, with some restrictions.
I also highly recommend a book entitled Cadaver Dog Handbook: Forensic Training and Tactics for the Recover of Human Remains, by Andrew Rebmann, Edward David, and Marcella H. Sorg. More than any other book, it gives you everything you need to know about the discipline.
Thank you, Cat! Please give Solo a hug from me and tell him I said “bravo!”
What scent games does your dog enjoy? And if you have any questions for Cat Warren, you may post them in the comment section.
Interested in Cat’s book, What the Dog Knows? It hit the #7 spot for bestselling paperback nonfiction. Check it out on Amazon!