Caterpygmies are more xenophobic even than Anthroaches and Arachane. Caterpygmies live in great silken weblike nests high in the treetops of the swamp, far from the mammals they despise. Caterpygmies perceive mammals as irrelevant and generally ignore them unless their community is threatened. Both Caterpygmies and Fritillaries have a deadly fear of Arachane, fleeing if such are near. Anthroach territory is forbidden to Caterpygmies and therefore the Anthroaches do not have much contact with them. The Alligataurs have a long standing enmity with the Caterpygmies.

The greatest threats Caterpygmies can encounter are the giant eagles and giant owls that frequently feed on them. The Caterpygmies refer to themselves as "Caterpyge", both singular and plural, and consider the term "Caterpygmy" derogatory. Caterpygmies are led by the Fritillaries.