The scent-tracking abilities of trained dogs have helped archaeologists discover iron age tombs in Croatia dating back nearly three thousand years.

The dogs sniffed out burial chests containing human bones and artefacts in a hilltop fort in the Velebit mountains along the Adriatic coast. Experts have said that using dogs could be a good way to identify archaeological sites, as it is less destructive than many traditional methods.

“Dogs’ noses obviously don’t make mistakes,” said Vedrana Glavaš, an associate professor of archaeology at the University of Zadar in Croatia and the lead author of the study, which was published in the Journal of Archaeological Method and Theory.

Glavaš had already found a few tombs in a necropolis near the prehistoric hilltop fort of Drvišica, which dates back to the eight century BC. Hoping to find more, she contacted Andrea Pintar, a trainer who works with dogs used for sniffing out graves in criminal investigations.

Facebook Twitter Pinterest Bronze buttons discovered during an excavation. Photograph: Department of Archaeology/University of Zadar

Pintar brought Belgian malinois and German shepherds to the remote site in 2015. Glavaš first sent the dogs to graves they had dug up the previous year but which were not apparent, without telling the trainers the location.

“We always use at least two dogs to confirm the position,” Glavaš said, adding that the second trainer and dog were not told where the first dog and trainer had indicated a grave.

The canines discovered all three graves, even though the human remains, associated artefacts and surrounding soil had been removed. The area had also been exposed to wind, sun and rain since the excavation.

Glavaš said the porous rock around the excavated soil had probably absorbed enough of the aroma of decomposition that the dogs could still detect it.

Glavaš then let the dogs loose in an area they suspected more remains could be found, and excavated six new tombs – five of which are described in the recent paper.

The dogs were extremely accurate in every case. The tombs consist of small stone burial chests in the middle of walled stone circles, each about five metres in diameter. Each chest contained small bones such as the fingers and feet of several individuals – perhaps several generations from the same family – along with buckles and other artefacts.

Glavaš said the people in the site were probably fairly poor due to the harsh, windy climate of the area and the difficulty of growing crops.

While Glavaš has used dogs successfully in other sites in Croatia and Germany, she has yet to excavate some of the tombs located by them in Drvišica due to a lack of time and money.

Facebook Twitter Pinterest One expert said it was likely the dogs could still detect the aroma of decomposition. Photograph: Zlatko Bala�/Department of Archaeology/University of Zadar

Angela Perri, a postdoctoral archaeology researcher at Durham University who was not involved in the study, said using dogs to sniff out burials was an especially promising technique as it is non-destructive and can be used in situations where ground-penetrating radar or other techniques may not work.

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

Perri, who studies the ancient history of how humans first began to domesticate and use dogs, said the technique was just the latest in humans’ long history of using dogs as biotechnology. “We’re still finding new ways of having dogs help us,” she said.

Glavaš believes archaeologists could use dogs in numerous different contexts. “Many archaeologists are looking for burial sites of settlements,” she said. “I think dogs can solve their problems.”