I have previously presented some evidence concerning the possibility of a Baltic zodiac, documented by archaeological artefacts and supported by historical sources (Vaiškūnas 2000). It seems clear that such knowledge was imported into the Baltic region from Classical and Medieval cultures to the south. If the Baltic zodiac was a simple copy of the Mediterranean one, it would be of minor interest for the iconography of Baltic constellations, but in the Baltic versions we observe very important differences from the Classical model. In this paper I analyse the relevant traditions in more detail and discuss these differences in the hope that it can offer us valuable information about sky mythology in northern traditions.