On the banks of the Solo River in Java, Indonesia, 19th-century physician Eugene Dubois uncovered an astounding fossil find: the bones of what appeared to be an ancient human, surrounded by animal ...

Figure 1: Holes in unionoid shells.

Homo erectus on Java was already using shells of freshwater mussels as tools half a million years ago, and as a 'canvas' for an engraving. The discovery of an engraved geometrical pattern on one of ...