THERMOREGULATION
The optimum temperature range for snakes is 18-34° C. Temperate snakes have a preferred body temperature of 24° C and tropical snakes favor around 28° C. Heat stress occurs at 35° C and death at 38-44° C.
When the temperature drops to 10° C the snake goes into torpor and will die if it is reduced to below 4° C.The tropical regions provide ideal temperatures for snakes and this is why the greatest variety of diurnal and nocturnal species are found there. In temperate climates snakes are usually diurnal, basking in the morning sun to heat up and hibernating in winter. Subtropical snakes spend the hottest part of day under the substrate. In times of drought when food and water is scarce the snake will estivate to conserve water.
Their length enables snakes to have regional differences in body temperatures. Snakes have a very high ratio of surface area to body mass when uncoiled and so lose heat rapidly. When coiled this minimizes surface area to mass and this enables heat to be conserved.