SEOUL, SOUTH KOREA—The International Business Times reports that David Wright of Seoul National University thinks that Neolithic cattle herders may have contributed to the desertification of the Sahara as they spread west from the Nile River some 8,000 years ago. Cattle grazing and the loss of vegetation may have been enough to tip the balance from the green pastures of 6,000 years ago to the spread of scrub vegetation, changing atmospheric conditions, and less frequent monsoon rains. Wright wants to obtain cores from former lake beds in the Sahara to study the vegetation records. For more, go to “Stone Towns of the Swahili Coast.”