Certain resources allow long term human encampments if people know how to preserve and store food. There are recorded instances of Siberian reindeer hunters in May still living off mass kills made in late August. In many parts of Europe during the Upper Paleolithic, meat could easily have been stored over the winter simply by freezing it. Recent studies of animals killed in Upper Paleolithic sites show that , in some instances, people managed to live in the same location from September to March. They occupied other sites for shorter periods, probably as short as overnight. Shown here is a 19th century Eskimo meat cache made of boulders. When opened, it revealed the carcass of a headless caribou.