The researchers have been shedding light on the lost history of this unidentified people by studying their burial rituals.
The scientists have provided the first radiocarbon dates for unusual jar and log coffin interments found on exposed ledges high in southern Cambodia's rugged Cardamom Mountains.
Since 2003, they have been working to locate and survey 10 interment sites and to date them, using samples of coffin wood, tooth enamel and bone.
Senior Research Fellow Dr Nancy Beavan and lecturer Dr Sian Halcrow, both of the Otago anatomy department, working with colleagues from Cambodia, Australia, the United States and Scotland, have published the dating results of four sites in the international journal Radiocarbon.
This work shows that mysterious funerary rituals, which were unlike any other recorded in Cambodia, were practised from at least 1395AD to 1650AD.
This period coincided with the decline and fall of the Kingdom of Angkor, which was based in the lowlands.
"Funeral practices in the Angkor Kingdom and its successors involved cremation rather than anything remotely like those found at sites we are studying," Dr Beavan said.
This suggested that, in cultural terms, these unidentified mountain dwellers were a "world apart" from their lowland contemporaries.
She hoped this publication and her attendance at a radiocarbon research conference in Paris in July would bring "more international awareness" of the people they had been studying.
Partly because little had been previously known of them, it had been hard to obtain funding to support planned research.
She has been living and working in Cambodia since 2010, and the Cambodian Ministry of Culture and Fine Arts had been "very supportive".
