A number of factors may help account for the difference in biodiversity between low and high latitudes. A. Frogs, which survive temperature ranges from as low as -2℃ to as high as 41℃, are evidence that amphibians are independent of ambient temperatures B. Physical adaptations offer amphibians a number of ways to protect against extreme or dangerous climate conditions. C. Amphibians can increase their body temperature by exposing themselves to the sun (heliothermy) and by pressing against the ground (thigmothermy). D. Sunrise is the time when some amphibian species have the greatest need for thermoregulatory mechanisms. E. Avoidance behaviors, such as sheltering from the sun, as well as estivation and hibernation, help amphibians control their body temperature. F. Hibernation always involves digging deep holes in mud or sand, whereas estivation sometimes involves nothing more than hiding in deep rock crevasses.