Ecology of Eastern Australian Whipsnakes of the Genus Demansia

Body sizes, food habits and reproduction in eastern Australian elapid whipsnakes are described, based on dissection of 537 specimens. The four species studied are Demansia atra, D. olivacea, D. psammophis and D. torquata. Males attain larger body sizes than females in all species, and male-male combat is recorded in D. atra. The diet consists mainly of lizards, especially skinks. Female reproductive cycles are strongly seasonal in the two southernmost Demansia (D. psammophis and D. torquata), with ovulation in spring. In contrast, the tropical D. atra and D. olivacea apparently reproduce year-round. All four species are oviparous, with mean clutch sizes between 3 and 8 eggs. Inferred rates of bodily growth in Queensland D. psammophis are high, with sexual maturation at = 20 months of age in both sexes. Several colubrid snake taxa in other continents are remarkably similar to Demansia in morphology (slender body, long tail, large eyes) behavior (rapid movement, diurniality, terrestriality) and ecology (saurophagy and oviparity). These whipsnake characteristics are interpreted as adaptations to facilitate the chase and capture of fast-moving diurnal prey items, especially lizards.