Tadpoles of Limnodynastes peroni show no evidence of any ability to undergo thermal metabolic acclimation when kept at 15 degrees C and 25 degrees C for periods up to 75 days. When kept for 90-120 days, small differences were seen between rate-temperature curves of 15 degrees C and 25 degrees C history tadpoles. The reality of these differences as evidence for thermal metabolic acclimation is difficult to assess. An overall equation to describe the effect of temperature (T, C) and weight (W, grams) on oxygen consumption (QO2, ml g-1 h-1) is log10 QO2 = -2.13 + 0.05T - 0.48 log10 W, for which r2 = 0.86 (no. = 360). Q10 is 3.16 and in the relationship M +/- Wb (where M = oxygen consumption, ml h-1), the exponent b = 0.52. The results suggest that in tadpoles of L. peroni any adaptations to fluctuating temperatures may be behavioral rather than physiological or biochemical.