Dogs have helped law enforcement and search-and-rescue crews discover human remains for decades. But recently, a new group has enlisted the help of canines and their olfactory superpowers: archaeologists.

In a recent paper in the Journal of Archeological Method and Theory, Vedrana Glavaš, an archaeologist at the University of Zadar in Croatia, and Andrea Pintar, a cadaver dog handler, describe how dogs trained to find human remains helped them track down gravesites dating to around 700 B.C.

For The Guardian, Joshua Rapp Learn reports that the team tested the dogs at a hilltop fort called Drvišica along Croatia’s Adriatic coast. Previously, Glavaš had identified tombs in a necropolis near the fort and wanted to find more. However, the irregular, rocky terrain made it difficult to just randomly excavate suspected burial sites. So, in 2015, she decided to contact Pintar, who trains cadaver dogs typically used in criminal cases.

Cadaver dogs are champions at finding remains that are just hours and even several decades old. But the team wasn’t sure if sensitive canine noses could detect the scent of death—actually, the more than 400 scents of death; decomposition releases hundreds of complex compounds—after 2,700 years in the ground.

To test the dogs, Glavaš had them sniff around an area where they she had excavated three grave sites the year before. The human remains had been removed, and due to weathering, it was no longer apparent where the excavations had taken place. Two dogs, working independently, easily located all three spots.

They then allowed the dogs, Sattve and Mali, to sniff around another site where they suspected there were more graves. The dogs located six of the unique graves, which consist of a small stone burial chest containing small finger and toe bones and a few small artifacts surrounded by a walled stone circle. The paper describes five of those graves. The dogs located others, however, due to limited resources, Glavaš has not yet excavated those sites.

The study is a proof of concept that dogs could be used more extensively in archaeology as a non-destructive method of finding human burials, especially in rocky areas, like Drvišica, where ground-penetrating radar isn’t feasible.

“Many archaeologists are looking for burial sites of settlements,” Glavaš tells Rapp Learn. “I think dogs can solve their problems.”

But cadaver dogs can be hard to come by. Most are trained by volunteers who work with law enforcement when their services are needed. The dogs undergo a rigorous 18-month to 2-year training protocol before they are able to work in the field. But once they are ready for service, they are incredibly accurate and only seek out the scent of human remains. (Though occasionally they will alert to pig bones, which are often used in their training.)

“This method is excellent because dogs locate the scent of a decayed human body, which is specific to human beings,” Glavaš tells Joe Orovic at Total Croatia News. “No other creature smells like a human.”

In an interview with blogger Ann Marie Ackermann, Pintar says she does not believe the age of the bone matters as much as the environment in which it is found. Moisture, sunlight, and temperature all impact how much scent remains will give off. She says she believes the graves in Drvišica were relatively easy for the dogs to find since the bodies were laid on slabs of limestone. As they decomposed, the scent compounds leached into the rock, which has trapped them for centuries.

This is not the first time dogs have been used in archaeology, though it is by no means a common practice. In 2012, an Australian dog named Migaloo was hailed as the first trained “archaeology dog,” taught to pinpoint the scent of human bones and was able to detect a 600-year-old Aboriginal grave. Another dog named Fabel currently works with Swedish archaeologist Sophie Vallulv, who decided to investigate working with dogs during graduate school. Fabel has located bones up to 1,600 years old at a depth of five feet. But Vallulv believes that’s likely not the limit of Fabel’s capabilities.

The use of archaeology dogs is even happening in the United States. Last year, archaeologists with the Kettle Creek Battlefield Association, which oversees the Revolutionary War battle sites in Georgia, called in cadaver dogs to survey the area and locate the makeshift graves of fallen soldiers. The dogs located over two dozen graves. While the graves did not contain teeth or buttons—telltale signs of the men laid to rest there—ground penetrating radar did show they were shallow pits surrounded by rocks. It’s likely all traces of the bodies once in them decomposed over 240 years.

As the dogs prove themselves in the field, Durham University archaeologist Angela Perri, who was not involved in the study, tells Rapp Learn that using dogs is a promising technique, escecially if dogs could find bones hundreds or thousands of years old.

“It would be interesting to push the boundaries on that and see just how old you could get,” she says. “It seems like a pretty great way to move forward in archaeology.”