Body size of tiger snakes in southern Australia, with particular reference to Notechis ater serventyi (Elapidae) on Chappell Island

Insular gigantism was studied in tiger snakes on Chappell Island, Bass Strait, to determine which of 3 hypotheses (food availability, predation and/or social-sexual interaction) best accounted for large body size. Predictions of predation and social-sexual hypotheses were not consistent with evidence. Prey availability, and the correlations of clutch size and reproductive frequency with body size, provide an explanation for the selective advantage of large body size. This allows increased fat storage and provides a low surface-to-volume ratio conferring resistance to extreme temperatures or moisture. Both features are important when resources are saturating but very highly seasonal.