Humans have used psychoactive plants for their narcotic effects for thousands of years. Throughout Thailand, remains of betel nuts, plants used for their stimulant effects, have been discovered at burial sites. To learn more about the practice, an international team of researchers have examined 4,000-year-old teeth and found traces of compounds from betel nuts. This indicates that betel nut chewing has been practiced for thousands of years, if not more, in the country. The study is the first to detect ‘archaeologically invisible’ cues in dental plaque, revealing ancient behaviors and practices that otherwise could have been lost to time.

Decades ago, archaeologists discovered a sticky substance in a copper jar in an ancient Greek shrine. And until recently, the identity of the residue was still murky — is it a mixture of fats, oils and beeswax or something else? Researchers publishing in the Journal of the American Chemical Society have reanalyzed samples of the residue using modern analytical techniques and determined that it’s likely the remains of ancient honey — a conclusion previous analyses rejected.

A University of Kansas researcher recently published a reexamination of ancient human migratory routes from Africa, where homo sapiens first evolved, based on a newly improved glacial isostatic adjustment (GIA) model of historical sea levels along with DNA and archaeological data. An improved simulation of ancient sea levels can reveal how melting glaciers — continuing long after the Last Glacial Maximum — may have transformed migration pathways and shaped the rise of civilizations in Africa.