BORDEAUX, FRANCE—Ars Technica reports that evidence for the use of ochre spanning a period of 4,500 years has been uncovered at Ethiopia’s Porc-Epic Cave. Daniela Rosso of the University of Barcelona and the University of Bordeaux and her colleagues examined more than 4,000 pieces of ochre recovered from the cave in order to try and determine how it was processed and used some 40,000 years ago. Microscopy and experimental grinding techniques revealed that the rocks were probably ground into powders for decoration and art, rather than for making adhesives and tanning hides. The techniques used to produce the powders changed slightly over time, as did the color preferences and the range of colors in use. Rosso and her team suggest the symbolic use of ochre in the cave may have been part of a cultural tradition shared by community members. For more on the use of ochre, go to “The Red Lady of El Mirón.”