The search for the most destructive invasive species in Florida has gone to the dogs.
The giant African land snail eats 500 kinds of plants and even chomps on the stucco on the walls of houses. In the two years since the snails were first discovered proliferating in a Miami neighborhood, state officials say they have found and killed 128,000 of them.
In a news conference last month, Florida's commissioner of agriculture, Adam Putnam, attributed some of that success to what he called "canine detector teams" — in other words, dogs that had been trained by the U.S. Department of Agriculture to track the snails' mucus trail.
The USDA's snail-sniffing dogs — Bear, Sierra and RJ, all Labrador retrievers — are part of a national trend to employ old-fashioned olfactory detection in new ways.
Using dogs to find bombs and drugs is old-school. Now dogs' sensitive schnozes are being put to work finding everything from illegal elephant ivory to contraband sea horses to the root fungus killing pine trees across the South.
In Florida, dogs have even been trained to sniff for bat guano. Why make them hunt for something so gross? To help U.S. Fish and Wildlife Service biologists locate the habitat of the elusive bonneted bat, which last year was proposed for addition to the endangered species list.
"It's just the same as training a dog to find bombs or drugs," explained Todd Steury, a wildlife ecology professor at Auburn University who works with a group called EcoDogs that has sniffed out skunk poop and weasel scat to aid scientists. "You teach them to associate a scent with a reward."
EcoDogs takes a different approach to their training from the USDA's venerable training center in Georgia. The USDA dogs are trained to associate the location of their target with getting a snack. Instead of food, the EcoDogs get a ball to play with.
"We look for dogs that have a very strong ball drive," Steury said. "Some of them will work themselves to death to play with that ball. They love what they do."
Bart Rogers, a trainer with Auburn's EcoDogs, took two Labs on the bonneted bat search, Baxter and Felix, both 3-year-olds. He also took some very low expectations.
"That's probably the rarest bat species in the United States," Rogers, 26, said. "I totally expected to work 21 days and not find anything."
Florida bonneted bats are the state's largest, with a wingspan of 19 to 21 inches. Their name comes from their broad ears that slant forward over their eyes as if wearing an old-fashioned bonnet. Biologists estimate there are no more than a few hundred of them, roosting in hollow trees in places like the Picayune Strand State Forest near Naples and eating their weight in insects every night.
Sniffing out their fecal remains is a subtle talent, Steury explained. "Bear poop has an odor you can pick up 100 yards away," he said. But bat guano is smaller, so its smell is less pungent.
Rogers and his dogs hunted the bats in places like the Babcock-Webb Wildlife Management Area near Punta Gorda. Working eight to 10 hours a day for 21 days, covering a total of 165 miles, Rogers' dogs located "one piece of pill-size guano" that might be from a bonneted bat, he said. DNA tests that would settle the matter have not yet been concluded.
This wasn't Rogers' first foray into Florida with the EcoDogs. In 2010 and 2011, he participated in a test to see if dogs could do a better job than humans in tracking down the pythons that have virtually taken over parts of the Everglades.
Rogers' dogs found pythons more often, and found even the littlest ones, said Christina Ramagosa, a University of Florida professor who worked on the testing. He took a dog out to an Everglades tree island where someone had spotted a snake "and the dog found it in a matter of seconds," she said. "It was a female with 19 eggs."
However, they learned that the humidity affected the dogs' ability to find the pythons. The Florida heat gets to the dogs pretty quickly, too. They couldn't hunt for as long.
As for the giant African snail search in Miami, the USDA dispatched handler Jodi Daugherty to spend a month training the three dogs to hunt for the snails, which were allegedly smuggled into Florida by a religious cult that used them in its ceremonies.
The agency picked Labs instead of the beagles used at airports, said supervisor Aaron Beaumont, because the Labs are hardier and less likely to get distracted. The dogs were trained to sniff out "the mucus, the live snail, the shell — the whole thing," he said.
State officials regarded the use of the USDA dog team as a test. They passed, finding not only some snails that had been planted as part of the experiment, but also two more that were wild. As a result, look for handlers for a couple of snail-sniffing dogs to be added to the state's own payroll soon, at an estimated cost of $250,000.
"We are currently in the recruiting process of hiring two permanent canine handlers to be dedicated to working on the eradication program," said Denise Felber of the Florida Department of Agriculture and Consumer Services. "We are hopeful to have handlers and canines working in the field early next year."
Researcher Caryn Baird contributed to this report. Craig Pittman can be reached at firstname.lastname@example.org.