Since a canine nose is equipped with some 200 million more olfactory receptors than a human's, scientists are increasingly turning to dogs as field assistants to track and monitor populations of wild species.
Such "conservation dogs" can sniff out creatures as small as a lizard or as large as a gorilla, pinpoint where invasive plants are growing, and even guide marine biologists to fresh whale poop. (See pictures of scat research.) But can a dog smell the past?
Australian dog trainer Gary Jackson of Multinational K9 has trained a black lab mix named Migaloo as the world's first "archaeology dog," able to locate bones that are hundreds of years old. He spoke with National Geographic magazine's Amanda Fiegl.
What gave you the idea to train an archaeology dog?
I like to experiment with things that have never been tried before. I've trained dogs to find cane toads, koalas, lots of unusual things. So I thought: Can you imagine the discoveries in archaeology that could happen around the world, if dogs could be trained to locate human bones? For years, people have been training cadaver dogs to find decomposed bodies. But the problem with that is at some point rot becomes the primary odor rather than the actual human odor. And many things are rotting throughout a forest. By training the dog on just human bones, you eliminate those distraction odors.
Why did you think Migaloo would be good at this kind of work?
She was a rescue dog from out in western Queensland, a black Labrador with a small cross of mastiff. Her name means "white fellow" in Aboriginal—it's an oxymoron. She loves to play, and she's an absolute nut about her ball. I think she would chase it till she drops dead. So, once we trained her to recognize the odor of human bones, and taught her that she only gets her ball when she finds the target odor, she became obsessive with trying to find that odor. (Also see video: "Poop-Sniffing Dog Tracks Predators.")
Now, I just have to bounce the ball a few times and say: "D'ya want this? Find." She'll go out and start sniffing like a hyperactive kid, and before long she lets me know: "I've got something!"
How does she let you know?
She focuses on one spot, and kind of goes crazy until I say "show me." Then she'll put her nose on the ground and start moonwalking backward from the spot where she smells it.
Did you bury bones in certain spots to train her?
Yes, we got permission from the Aboriginal tribal elders to use some ancestral bones from the South Australian Museum's collection. So we re-created an Aboriginal graveyard, and also scattered some animal bones there. What we saw was that the dog was able to find a buried bone from about ten feet (three meters) away, even if it's as small as a fingernail. We would even just take a cotton ball and touch the bone, and touch that to the rock—and she could still find the smell. (See blog: "Dogs Sniff Out Exotic Pythons in the Everglades.")
Also, we knew of an Aboriginal burial tree that had been found in 1970. They had knocked it over while building a golf course and a skull had rolled out. We figured other bones were still in there, so we took her to that golf course. She zeroed right in on that tree and went crazy.
What's the oldest bone she has found?
The big test was at an Aboriginal burial ground in South Australia, where a 600-year-old grave had been found a few years ago. We were given about an acre (0.4 hectare) to search. Museum officials and tribal elders were there—they knew where the graves were, but not us. Within two minutes, Migaloo was circling this one spot. (See dog pictures readers have submitted to National Geographic.)
She stayed on top of it, started digging, laid down, and jumped back up. So then I asked: Is there something here? And they said yes: exactly where the dog was, is that 600-year-old grave. That was remarkable, because you know bones that old don't have any flesh on them, they're completely dry, yet she still smells something.
Do you worry she might damage artifacts by digging or putting them in her mouth?
No, Migaloo only digs if I don't reward her right away. And she has no interest in the bones other than finding them. She just wants the ball!
What's next for Migaloo?
We're starting to look at not only human remains, but cross-training her on pottery and fossils. Is it possible that dogs can find dinosaur remains? Ancient pots? We're looking at all these scenarios now. And we're hoping to be able to take Migaloo to France and Belgium next year to try to discover some lost WWII graves on former battlefields that are now farmland. That would be so special, to be able to get closure for the families of Australian and American soldiers who died over there.
Can other dogs be trained this way?
Definitely, if they've got the drive. And more dogs coming on board could open up a whole stack of cold cases. Police might suspect someone's buried in a backyard, for example—they can have a dog find out for them quickly and easily. This could help Aboriginal tribes prove the location of sacred grave sites, instead of having to actually dig up their ancestors to protect the land from development.
I'm hoping to inspire other trainers to take the lead and continue with this, now that they see it's possible. Families will be able to bury their relatives, cold cases will be solved, archaeologists will be able to make new discoveries. Migaloo will start it, but there's going to be many great dogs that will follow in her footsteps. It's going to be great for mankind.