GUAYAQUIL, ECUADOR—According to a statement released by the Polytechnic School of the Coast, between 1,500 and 400 years ago, hunter-gatherers consumed guanaco, armadillo, birds, and large rodents at the site of Zoko Andi 1, which is located in Argentina’s transition zone between the Pampas and Patagonia. Gustavo Martínez of the National University of Central Buenos Aires and his colleagues determined that this use of the site is about 500 years earlier than previously thought. In addition to serving as a camp, the site may have been used for ritual purposes, since burials were also uncovered. This connection to ancestors may have continued to draw people to the site for centuries, the researchers...