EFFECTS OF TRAINING AND CAPTIVITY ON THE METABOLIC CAPACITY OF THE LIZARD SCELOPORUS-OCCIDENTALIS

The effects of training and captivity on the running performance and selected metabolic and biochemical variables were investigated in the lizard Sceloporus occidentalis (Sauria: Iguanidae) in two studies of 6 and 8 weeks duration. Resting and maximal oxygen consumption, lactate concentration of the blood and whole body, and enzyme activities in skeletal muscle were compared among trained and untrained-captive animals taken recently from the field. No significant changes in these metabolic and biochemical measurements occurred as a result of training or of captivity. Distance run to exhaustion and the running endurance of these animals also failed to change in a way attributable to the experimental treatments. Training and captivity appear incapable of altering the maximal rates or the components of metabolic energy production in S. occidentalis. This inflexibility is in contrast to the adaptability and plastic nature of the metabolic capacities exhibited by captive and domestic mammals subjected to varying amounts of chronic activity. © 1979, Springer-Verlag. All rights reserved.