Las Vegas Sun

March 28, 2024

Researcher trains dogs to sniff out tortoises

For years, an ecologist at Nevada's Desert Research Institute has tried to convince fellow scientists that search dogs might be the answer to tracking the elusive, threatened desert tortoise. What a ridiculous notion, they said.

Finally, Mary Cablk has proven them wrong. Last year she conducted experiments that demonstrated that trained German shepherds are expert scouts of the rare animals, and she is getting ready to do further tests.

"We've sort of proven that it wasn't such a crazy idea," Cablk said.

Cablk's research has the potential to save the lives of countless tortoises threatened by desert development and to allow researchers to gain insight into the creatures.

Her study is a new frontier in the already broad portfolio of uses for dogs' phenomenal sense of smell. While dogs have previously been used to find animal droppings, "this is the first research study to use dogs for wildlife detection," Cablk said.

In tests conducted in April at the Bureau of Land Management Desert Tortoise Conservation Center, southwest of Las Vegas, Cablk and biologist Jill Heaton found that the dogs successfully found the tortoises more than 90 percent of the time, regardless of conditions and the turtles' size and age.

The dogs were able to locate tortoises more than 200 feet away. With their acute noses, the dogs could find tortoises that were hidden to the eye in burrows or behind bushes -- they could even work at night.

By contrast, people can find tortoises in the landscape only 30 to 60 percent of the time, Cablk said.

Cablk wasn't surprised the dogs proved so able. In addition to her work as a scientist, Cablk is a volunteer Washoe County deputy whose search and rescue dog, Mica, is licensed in both Nevada and California and certified for avalanche, wilderness and cadaver work.

"As I trained my dog in a variety of disciplines, it was amazing to me what they can do," she said. That gave her the tortoise inspiration.

The institution that finally gave Cablk's "crazy idea" a chance was the University of Redlands, in California, which granted a relatively small $50,000 for the project out of federal endangered species funds.

Based on the success of the initial research, Cablk and Heaton are negotiating for a much larger grant from the Army's Ft. Irwin, in California, which needs to relocate tortoises from a large area of desert in order to expand.

For the original experiment, the researchers trained the dogs with pieces of gauze that had been rubbed on the turtles' heads and necks. Then they tethered tortoises at random locations over a large area and sent the dogs after them.

The dogs were taught to turn toward their trainers when they located a tortoise.

The essential question, Cablk said, "was, can dogs find tortoises? Because we don't know, for lack of a better word, how 'smelly' they are. And if they can find them, can they do it safely? And how reliable are they?"

The tortoises turned out to be plenty smelly -- even to humans, they have a noticeable odor, Cablk said. But the question of safety was a troublesome one.

Many observers believe feral dogs in the Mojave Desert are partly to blame for declining tortoise populations, although the evidence is sketchy. Thus, there was resistance to allowing dogs to come in contact with tortoises, Cablk said.

"But think about it," she said. "Bomb dogs don't detonate the bombs they find. The dogs can be trained not to interact with the objects they locate."

Some also feared that, by tracking down the tortoises, the dogs would draw attention to them, inviting coyotes and other predators to the spot. But Cablk's tests found that the risk was no greater than with human tortoise-finders.

The research scheduled for later this year will put the dogs in the real desert, with tortoises not planted by humans, to see how the canines do with the wide distribution of tortoises in the desert -- sometimes just a couple of tortoises per square mile.

The desert tortoise, which the federal government lists as a threatened species, is native to the Mojave Desert. Largely because of the difficulty of finding the animals, scientists don't know how many of them there are.

Seeking to protect the tortoise, a federal judge in San Francisco last week ordered that off-road vehicles be banned from more than a half million acres in Southern California.

The dogs' potential to help scientists is huge. Despite years of study, not very much is known about the tortoises' habits in the wild. Among the questions tortoise-sniffing dogs could answer, Cablk said: "Do they stay in their burrows at night? Do they come out and forage? Do they move around?"

If the dogs pass their next test, Fort Irwin's 120,000-acre expansion won't bulldoze any of the threatened reptiles, although researchers still don't know whether or not tortoises can thrive when relocated.

"The more tortoises we move out of that area, the fewer are in harm's way," Cablk said.

With Nevada's continuing growth pushing urban boundaries ever outward, the question is not whether the tortoises will be displaced, but if they will survive their displacement, she said.

"Development is happening," Cablk said. "It's just critical that we learn as much as we can about tortoises so we can help them continue as a species."

archive