The 14,000-year-old mummification secret: They preserved the dead by incensing them

According to CNN's report citing research published in the US-based PNAS journal, the practice of incensing the dead is still a technique used in Papua New Guinea.

Previously, the earliest examples of mummification were seen in the Chinchorro culture of northern Chile, dating back about 7,000 years, and in Ancient Egypt, about 4,500 years ago.

Thousands of years ago, people would wait and dry their dead by placing them in a crouched position over the smoke of a low-temperature fire, then carry the mummified body to the burial site.

While traces of smoking were found in bones taken from nine regions in the study, the oldest example was seen in an arm bone from Northern Vietnam that showed signs of burning, dating back approximately 14,000 years.

Most other similar examples were found in graves dating back to 12,000 to 4,000 years ago.

Dr. Hsiao-chun Hung, a senior research fellow at the Australian National University and lead author of the study, told CNN that their research reveals a unique interaction between technique, tradition, culture and beliefs in pre-Neolithic cultures in southern China and Southeast Asia.

Hung noted that this practice continued for a surprising period of time and across a wide region, noting that in the Neolithic period and before, the incense method "could only be sustained with deep love and spiritual devotion."