Further Observations on Thermoregulation in the Brooding Female Python molurus bivittatus (Serpentes: Boidae)

Resting oxygen consumption of a gravid Python m. bivittatus increased appreciably, and weak spasmodic contractions of the body began before eggs were laid. Contractions increased in frequency and strength at oviposition and were accompanied by a rapid rise of oxygen consumption and body temperature. The incubating female responded to a decrease in ambient temperature ( T A) with an increase in oxygen consumption and contraction rate and was able to maintain a stable body temperature ( T B) above 33 C until T A fell below 26 C. At a T A of 23 C the temperature differential T B- T A was 8.3 C and oxygen consumption had increased to a mean of 169 ml O2 kg-1 hr-1, 20 times that of the non-gravid animal at the same T A. An increase of T A caused a decrease of contraction rate and oxygen consumption. Mean daily oxygen consumption of the eggs during the last 9 days of incubation ranged from 110 to 130 ml O2 kg-1 hr-1. Mean standard metabolic rate of day-old hatchlings was 124 ml O2 kg-1 hr-1 at a T A of 28 C. Air samples from among the eggs inside the body coil during incubation had a CO2 concentration of 1%. Standard metabolic rate of the non-gravid animal increased with temperature, but not in a simple, exponential fashion.