Life-history and diet of two populations of Natrix maura (Reptilia, Colubridae) from contrasted habitats in Sardinia

摘要: Aspects of general ecology and population biology two populations freeliving viperine snakes (Natrix maura) were studied in Mediterranean localities the island Sardinia (Thyrrenian Sea, Italy). The apparent adult sex-ratio was not significantly different from equality, but males slightly more numerous than females. diet consisted mainly arnphibians, both adults tadpoles (area A) or fish B). Females longer males. Reproduction yearly, clutch size female total length positively correlated. A hundred seven live offsprings obtained 135 eggs (79.2% successful incubation rates). proportion unsuccessful correlated with either size. There no evidence a trade-off between offspring size, as hatchlings smaller clutches that unusually large relation to maternal body Oviposition date neither nor lncubation period mean hatchling length. No died after oviposition, thus suggesting very low incidence mortality rates dueto starvation reproductive costs. case long-term sperm storage deriving autumnal mating is described. Population estimates are provided for study areas. Key words: Natrix maura, Ecology, region, Sardinia.