 The optimum body temperature range varies with species, but is typically below that of warm-blooded animals; for many lizards, it falls in the 24°–35 °C (75°–95 °F) range, while extreme heat-adapted species, like the American desert iguana "Dipsosaurus dorsalis", can have optimal physiological temperatures in the mammalian range, between 35° and 40 °C (95° and 104 °F).While the optimum temperature is often encountered when the animal is active, the low basal metabolism makes body temperature drop rapidly when the animal is inactive.As in all animals, reptilian muscle action produces heat.