It has been proposed by scientists that reptile scales are an evolutionary adaptation to prevent desiccation and to regulate body temperature. The authors of this article report on an experiment that was performed to test this hypothesis. The scientists examined the physiological role of snake scales by making measurements of a normal, scaled snake and a scaleless snake and comparing the resulting values.

The two snakes were both hatchlings, were similar in size, and were collected from the same region in California. Both snakes were provided with food and water while they were allowed to adjust to captivity for a month. The scientists made three types of measurements and comparisons between the normal snake and the scaleless snake. The first was a comparison of tissue samples taken from the dorsolateral region. The second set of measurements was of oxygen consumption and evaporative water loss rates. Each snake was suspended in a darkened chamber set at 28^o C to stimulate natural environmental conditions. The snakes were exposed to dry air, which the scientists then measured to determine changes in relative humidity and oxygen content. In the third set of measurements, the experimenters measured the rates at which the snakes gained or lost heat by monitoring the body temperature of the animals. After each snake was first equilibrated to 15^o C then exposed to 33^o C, the rate of increase in body temperature was measured. The experiment was repeated, but this time the snakes were first placed in a 32^o C environment and then put in a 15^o C chamber to determine the rate at which the snakes lost their body heat. Each set of heating and cooling measurements was conducted five times for both snakes.

The results of the tissue sample comparisons show that while the normal snake contained a large amount of both a- and b-keratin, the two types of keratin normally found in the epidermal layer, the scaleless snake contained normal levels of a-keratin only; the b-keratin layer was greatly reduced. The results of the water loss and oxygen consumption experiments show that the rates for the normal snake and for the scaleless snake were very similar. Finally, the results of the heat transfer experiments show that the rates of heating and cooling were very similar for the two snakes. Moreover, the rates of heating were similar to the rates of cooling for each individual, a result that the authors found interesting because it did not agree with results from similar experiments performed on large lizards.

In conclusion, the authors found no empirical evidence that supported the hypothesis that reptile scales are important in preventing water loss or mediating heat transfer. The authors suggest, however, that scales may play an important role in maintaining the reptile's body temperature in ways other than convective transfer. They state that additional experiments to test these alternative methods would need to be conducted before any effect on body temperature can be ruled out.