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Of Biosensors and Buddy's Nose

The German Shepherd zigzags across the raw, snow-patched earth ahead of his handler, nose to the ground. Suddenly he stops, concentrating on a bit of earth no different from any other to human senses, then begins to dig furiously. His handler rewards the dog with a tidbit and an affectionate hug, flags the spot the dog has marked, then sends the dog out ahead again, searching for more pipeline leaks.

Pipeline leaks? Found by a dog?

Back in 1974, a new buried natural gas pipeline was due for opening in Ontario. The line, however, leaked -- and engineers and scientists using every bit of technology at their disposal had been unable to find the leaks. Sections of the pipeline would literally burst from overpressure before the leak rates became high enough to be detected. The line was due to be opened in just nine days when someone thought to consider dogs and contacted dog trainer Glen Johnson.

Johnson took three dogs already trained in scent work, and in two and a half days taught them to dig for a buried article where they smelled the butyl mercaptan used to "odorize" the natural gas. Then they tackled the first twenty miles of the pipeline, where the pipeline workers thought there might be three small leaks. The dogs found twenty the first day. "Impossible," was the verdict -- until the indicated sections were dug up and the leaks finally found. Eventually, the dogs found 150 leaks.

Where odorous compounds are concerned, technology still cannot match a dog's nose. The dogs on the pipeline were identifying odors at forty feet that chemists could not detect at all, and were responding to concentrations in the parts per trillion range.

People probably domesticated dogs to use their noses in finding game, and that ability must have been extended to the finding of lost children and fugitives very early. Sherlock Holmes used a tracking dog in one of his cases, and the fugitive slave or criminal pursued by slavering bloodhounds is a stock piece of American fiction. (In fact, the bloodhounds drool because of the loose facial skin which helps direct scent to their noses, and would be more likely to drown an escaped prisoner as they licked his face than to attack.)

In this technological century, we have found new ways to utilize the dog's nose. Dogs have been used to detect gypsy moth egg masses, fire accelerants used by arsonists, drugs, explosives, firearms, utility line leaks under the streets of downtown New York, and termites, as well as the more traditional victims of avalanches, earthquakes, and just plain getting lost.

Dogs' noses are also used in sport. Hunting dogs are well known, but dogs of all breeds can compete in advanced obedience work, where one of the things they must do is to select an article touched by their handler from a group of similar articles. Then there's sport tracking, where the dog must follow the trail of a stranger and identify an object dropped by that person. Many search and rescue dog teams have started out in sport tracking and graduated to real-life rescue work.

Here in Alaska there are three volunteer search and rescue dog groups: SEADOG in Juneau, ASARD in Anchorage, and PAWS in Fairbanks. Tracking tests -- sport tracking trials -- are held in both the Anchorage and Fairbanks areas. (This year, the Anchorage area test is 95 miles up the Parks Highway on August 19, and the Fairbanks tests -- along with a seminar by Glen Johnson, who'll be one of the Fairbanks judges -- are Labor Day weekend.)

Thus far, to the best of my knowledge, dogs in Alaska have not been involved in detecting tiny pipeline leaks. But if a similar problem ever arises here, we should keep in mind that these furry, four-legged biosensors, self-repairing, self-propelled, user-friendly, and operating on renewable resources, have demonstrated their ability to outperform modern technology at finding things that smell.