The taipan, Oxyuranus scutellatus, is a large slender elapid of coastal tropical Australia. The small-scaled snake, O. microlepidotus, is a similar snake from the arid zone. These are among the most highly venomous snakes in Australia, and probably in the world. We present information on body sizes, sexual size dimorphism, feeding habits, reproductive cycles, fecundity and inferred growth rates, based on dissection of museum specimens and observation of captive snakes. Adult snakes average approximately 1.5 m SVL in both Oxyuranus species, and males and females attain similar body sizes. Oxyuranus species are unique among Australian elapids in feeding exclusively upon endothermic prey. A wide variety of marsupials and rodents is taken: especially Rattus villosissimus and Antechinomys laniger by O. microlepidotus, and Melomys sp., Mus musculus, Perameles nasuta and Rattus spp. by O. scutellatus. The large body size, highly toxic venom and 