There are several variations in Greek mythology regarding the battle between the pygmies and the cranes. According to Hecataeus of Miletus, the pygmies fight to protect their fields from the migrating cranes who hated them becuase of their small size. The pygmies retaliated by stealing the crane's eggs and young. The battles depicted on Greek vases, beginning with the François Vase, are perhaps best considered as representations of the theater. See Swindler, "A Terracotta Altar in Corinth," in AJA 36 (1962), pp. 515-517.