STANDARD AND MAXIMAL METABOLIC RATES OF GOANNAS (SQUAMATA, VARANIDAE)

Standard metabolic rate and maximal metabolic rate during forced exerc ise are examined for nine species of goanna (genus Varanus), with body mass varying from 10 to 3,750 g. At 35 degrees C, the common pooled m ass exponent for standard metabolic rate is 0.97 and at 25 degrees C i t is 0.89, with considerable variation between species (0.43-1.20). St andard metabolic rate at 35 degrees C scales interspecifically with bo dy mass(0.92) and at 25 degrees C with body mass(0.87). The Q(10) for standard metabolic rate is approximately 2.5 between 25 degrees and 35 degrees C. At 35 degrees C, maximal metabolic rate scales intraspecif ically with body mass(0.79) and scales interspecifically with body mas s(0.72). Factorial metabolic scope ranges from nine for the larger spe cies to 35 for the smaller species; it scales with body mass-(0.199) a t 35 degrees C. The maximal metabolic rate of 6.36 mL O-2 g(-1) h(-1) for Varanus caudolineatus is the highest recorded for any squamate. Va riations from the interspecific regression line appear to have some ec ological significance. Varanus tristis (a widely foraging arboreal goa nna) and Varanus eremius (a widely foraging terrestrial goanna) have a higher standard metabolic rate than Varanus acanthurus (a sedentary t errestrial goanna). The three arboreal goannas (Varanus caudolinentus Varanus gilleni and Varanus tristis) have a higher maximal metabolic r ate than the terrestrial species (Varanus brevicauda, V. eremius, V. a canthurus, Varanus gouldii, Varanus rosenbergi, and Varanus panoptes).