Comparative Ecology of Three Australian Snake Species of the Genus Cacophis (Serpentes: Elapidae)

The elapid snake genus Cacophis consists of three small nocturnal species, widely distributed along the eastern coast of Australia. Dissections of 550 museum specimens yielded data on food habits, body sizes, sexual size dimorphism, mode of reproduction, clutch sizes, growth rates and seasonal schedules of reproduction. Prey items include scincid, agamid and pygopodid lizards, lizard eggs, typhlophid snakes and myobatrachid frogs. However, > 70% of items belong to two scincid lizard genera, Lampropholis and Leiolopisma. Feeding occurs in all months of the year. All three species are oviparous, with mean clutch sizes of 3.2 (C. krefftii), 5.1 (C. harriettae) and 6.2 (C. squamulosus). Vitellogenesis commences in autumn, ovulation occurs in spring, oviposition in summer, and hatching in autumn. Growth of juveniles is rapid, with males of all three species attaining sexual maturity in the second spring after hatching (at the age of 20 months). Females also mature at this age in the small species C. krefftii, but maturity is delayed for another year in most female C. harriettae and all female C. squamulosus. Females attain much larger body sizes than males in all three Cacophis species. Growth after maturity is more prolonged in the larger species.