Metabolism, pulmocutaneous water loss and respiration of eight species of ground squirrels from different environments

Abstract

1. 1. The night time metabolism of eight species of ground squirrels ( Spermophilus spp.) is described by the allometric relationship: metabolism ( ml/hr) = 3·2G 0·66 ± 0·1176 (2 S.E.)—60 per cent of the metabolism for other mammals of comparable size. 2. 2. The circadian cycle of T b has an amplitude of 1·9°C, with a nocturnal T b of 35·7 ± 0·2 (2 S.E.) . 3. 3. The Q 10 of metabolism vs. T b between 1·96 and 5·4. 4. 4. The dry conductance of six species decreased at T a of 35°C and above. 5. 5. Breathing rate was 2·25−2·75 times minimal values resulting in 100 per cent dissipation of metabolic heat at T a between 38·7 and 42°C, inclusive. 6. 6. There were distinct differences between species in their tolerance to high T a .