Seasonal variation in metabolic rates and maintenance costs of the eastern fence lizard,Sceloporus undulatus

Metabolic rates of lizards, Sceloporus undulatus, differed between acclimated and acclimatized individuals. Oxygen consumption of field acclimatized Sceloporus undulatus peaked during the early morning and afternoon and was highest overall during spring. Oxygen consumption in the summer was similar to that in the fall. Laboratory acclimated animals collected during spring exhibited significantly lower rates of oxygen consumption than acclimatized individuals. Rates were similar in summer. Oxygen consumption did not vary between spring and summer for acclimated animals. Activity season maintenance costs of adult males based on field body temperatures and seasonal measurements of metabolic rates of acclimatized lizards (23.8 kJ/g) were higher than maintenance costs computed with data for summer lizards (20.6 kJ/g; a difference of 13.4%) and acclimated lizards (15.6 kJ/g; a difference of 34.5%).