JENA, GERMANY—Consumption of dairy products helped humans to survive in the Tibetan Plateau some 3,500 years ago, according to a BBC Science Focus report. Researchers including Nicole Boivin, Li Tang, Shevan Wilkin, Hongliang Lu, and Shargan Wangdue of the Max Planck Institute of Geoanthropology used paleoproteomics to analyze proteins in the calculus on the teeth of 40 people who lived at 15 different sites in the region. They found that milk drinkers included men, women, and children who all came from the northern and western areas of the plateau, in zones at more than 12,000 feet above sea level. Paleoproteomics also allowed the researchers to determine that the milk came from goats and sheep, and possibly cattle and yak. However, no evidence of milk drinking was found in the remains of Tibetans who lived in the southern areas of the plateau, where it was possible to grow crops. Further analysis of the dental calculus will try to determine what else the Tibetans consumed. For more on high-altitude living in the past, go to "The Heights We Go To."