The reproductive biology of Australian reptiles: a search for general patterns.

Egg size and fecundity vary greatly between species, and are correlated with maternal size in both interspecific and intraspecific comparisons. Species of large body size produce slightly larger young, and many more young, than do smaller taxa. Oviposition sites of most Australian reptiles are holes dug in moist sand or soil, but many species deposit eggs under logs or rocks. Specialized nest-sites include those of geckoes with calcareous-shelled eggs (enabling oviposition in drier micro-environments) and the elaborate mounds of saltwater crocodiles. Mating systems are poorly known: male combat has been recorded in many taxa, and seems to be correlated with sexual dimorphism in body size. The seasonal timing of reproduction is very consistent in southern Australia, with breeding restricted to the warmer months. However, tropical taxa display a variety of breeding seasonalities, ranging from continuous, to wet-season, to dry-season breeders. Parental care is recorded only from pythons and crocodilians, and takes very different forms in the 2 groups. Viviparity, sometimes involving placental transfer of nutrients, has evolved independently in at least 22 lineages of Australian squamates, primarily as an evolutionary response to cold climates. The proportion of viviparous lizards and snakes at any given site in Australia is highly correlated with environmental temperatures. -from Author