Tables
Table 1: Mean (± SD) evaporative water loss (EWL in mg/min) of agar frog models (3% agar) made from six anuran species. These values of EWL were used to correct the values of water exchange shown in Fig. 1. Mean body masses of the frogs used to make the models are given in Fig. 1.
Species Mean EWL n (mg/min)
Xenopus laevis 0.42 ± 0.02 4
Rana catesbeiana 4.7 ± 0.93 3
Rana pipiens 2.8 ± 0.42 4
Bufo boreas 2.5 ± 0.16 3
Pseudacris cadaverina 0.54 ± 0.15 4
Pseudacris regilla 0.53 ± 0.06 4
Table 2: Osmotic potentials of blood (mean ±SD) in six anuran species while at 100% and 90% standard body mass (the mass of a fully hydrated frog with an empty bladder) as measured using a freezing point osmometer. Sample sizes are given in parentheses. Water potentials at 90% hydration for all species were significantly higher (t = 1.995,P < 0.05) from those at 100% hydration. Letters designate osmotic potentials at 90% hydration that were statistically similar by Tukey HSD posthoc analysis (Q = 2.93, P < 0.05).
Osmotic Potential (-kPa)
Species Blood (100%) Blood (90%)
Xenopus laevis 581 ± 23 (6) 686 ± 29 (7) dRana catesbeiana 480 ± 32 (12) 580 ± 13 (6) dRana pipiens 593 ± 22 (7) 635 ± 31 (7) cBufo boreas 590 ± 7 (6) 685 ± 11 (8) bPseudacris cadaverina 635 ± 35 (4) 707 ± 13 (3) bPseudacris regilla 710 ± 44 (6) 842 ± 41 (9) a