Arboreality in Snakes: Ecology of the Australian Elapid Genus Hoplocephalus

Abstract

species. H. bitorquatus feeds mainly on arboreal pelodryadid frogs, H. bungaroides on lizards, and H. stephensi on lizards, mice and frogs. All species are viviparous, with ovulation occurring in late spring and birth in late summer. Young at birth are large (SVL 20 cm) relative to maternal size (SVL 50 to 70 cm), and litters are small (usually 4 to 6 young). Size-frequency distributions suggest sexual maturation at 3 to 4 years of age in H. bitorquatus. Most adult female Hoplocephalus reproduce only once every two years, or less often. Compilation of published data on snake faunas of several continents reveals that a) food habits of arboreal and terrestrial snakes usually are similar; b) arboreality is more common in some taxonomic groups (e.g. colubrids) than in others (e.g. elapids); and c) the proportion of arboreal species in a snake fauna is highly correlated with annual precipitation. These findings may explain why arboreality is rare in Australian snakes.