In Tasmania's relatively cold conditions keeping the young within the body allows the parent to have greater control over the incubation temperature and the chances of survival are increased. All over the world there is a trend towards live-bearing amongst reptiles in colder areas. Water Management Reptiles are well adapted to survive dry conditions. They do not lose moisture through their skins by sweating and land-dwelling reptiles conserve water by excreting their uric acid in a solid white pellet at the end of their droppings. In other words, these reptiles don't pee.
Many reptiles have other adaptations for life in a dry environment.
For example, all snakes and many lizards have a transparent scale permanently fixed over the eye. As well as providing protection for the eye, the transparent scale prevents moisture loss through evaporation. Most small Tasmanian skinks have a transparent scale in their lower eyelid which performs a similar function. These lizard normally close their eyes when at rest, but can still see. If there is any movement that might mean danger or food, they quickly open their eyes.