Intricate clay figurines like the one pictured above are the only clue archaeologists have to the mysterious Koma Land culture, which occupied part of northern Ghana between 600 and 1300 C.E. Many of the human figures have cavities carved into their nostrils, ears, mouths, or the tops of their heads. Archaeologists have long wondered whether people poured liquid offerings, such as palm wine or medicinal infusions, into these holes during rituals. Now, researchers have used ancient DNA to test that hypothesis. They used sterile swabs to sample the residue left in the cavities without damaging the figurines themselves. When they analyzed the samples, they discovered DNA from plantains and bananas, pine trees, and a variety of grasses. The grass species could have been local, but plantains and bananas are not native to Ghana, and researchers don’t think they were cultivated by the Koma Land people—although they were likely grown in other parts of West Africa. The closest pine trees, meanwhile, were on the other side of the Sahara Desert in North Africa. Pine needles and bark were often boiled to make medicinal infusions, perhaps making them a valuable commodity for African cultures at the time. The study, to be published in the March issue of the Journal of Archaeological Science, provides the first window onto the trade routes employed by the Koma Land people. It also provides more evidence that ancient DNA can be found in hot climates, something researchers once feared would be impossible.