Energy metabolism and body water turnover rates of two species of free-living kangaroo rats, Dipodomys merriami and Dipodomys microps

Water and energy metabolism in free-living multi-mammate mice,Praomys natalensis, during summer

“…Perognathus /ormosus exhibits maximum metabolic rates of about 5,6 ml C~/g h during the late northern winter months of February and March, about double the rates found in summer (Mullen & Chew 1973). Similar seasonal influences on metabolic rates have been found in free-living Dipodomys merriami (Mullen 1971). Increased metabolic rates during winter probably result from increased thermogenesis during cold conditions.…”

“…The metabolic rates in free-living P. noto/ensis are intermediate to those that have been reported for other rodents (Table 1). The ratio of water to energy use in P. noto/ensis was 0,14, which is much higher than the values reported for desert rodents; 0,04 to 0,07 ml/k1 (Mullen 1971;Withers, Louw & Henschel 1980).…”

Water and energy metabolism in free-living multi-mammate mice,Praomys natalensis, during summer

“…Perognathus /ormosus exhibits maximum metabolic rates of about 5,6 ml C~/g h during the late northern winter months of February and March, about double the rates found in summer (Mullen & Chew 1973). Similar seasonal influences on metabolic rates have been found in free-living Dipodomys merriami (Mullen 1971). Increased metabolic rates during winter probably result from increased thermogenesis during cold conditions.…”

“…The metabolic rates in free-living P. noto/ensis are intermediate to those that have been reported for other rodents (Table 1). The ratio of water to energy use in P. noto/ensis was 0,14, which is much higher than the values reported for desert rodents; 0,04 to 0,07 ml/k1 (Mullen 1971;Withers, Louw & Henschel 1980).…”

Energy Expenditure in Free‐Ranging Lizards

“…However, the ratio of cost of free living to maintenance cost is remarkably similar in these vertebrate groups: the ratios for lizards are 2.0 to 2.5 inS. occidentalis (Table 2) and 1.7 in Sauromalus obesus (Nagy and Shoemaker 1975); for birds, 2.8 in Progne subis (Utter and LeFebvre 1970) and 2.3 in Mimus polyglottos (Utter 1971); and for rodents (mean monthly averages), 2.8 in Perognathus formosus (Mullen 1970), 2.4 in Dipodomys merriami and 2.5 inDipodomys microps (Mullen 197Ia), and 3.5 in Peromyscus crinitus (Mullen 1971b). The primary reason for this discrepancy is that the free-living increment ratio is calculated from daily resting metabolism at both warm (diurnal) and cool (nocturnal) body temperatures for the lizards, so the denominator of this ratio is < 10--17% of endotherm levels stated above.…”

Field metabolic rates and water influxes of two sympatric Gerbillidae:Gerbillus allenbyi andG. pyramidum

“…Mass specific water influx in winter increased by 63.1% in G. allenbyi and by 62.5% in G. pyramidum when compared to their respective summer water influxes. For the two granivorous heteromyids, P.formosus (Mullen 1970) and D. merriami (Mullen 1971), these values were 58.7% and 56.6% of their predicted FMRs, respectively. FMRs of G. allenbyi and G. pyramidum were 69.3% and 74.5%, respectively, of those predicted for rodents of their body masses.…”

“…Means are ex-pressed+ SD and were compared using Student's t-test. Body mass (mb), total body water volume (TBW), water influx (WI), CO2 production (I2CO2) and field metabolic rates (FMR) of Gerbillus allenbyi and G. pyramidum in winter and summer Morris and Bradshaw (1981): WI (ml/day)=0.21 m b (g)0.9o c FMR predicted according to Nagy (1987): log FMR (kJ/day) = 1.022+ log m b (g) d Data from e Data from Mullen (1970) r Data from Mullen (1971) n = 33 in summer) in both winter and summer; intraspecific comparisons showed no significant seasonal differences in body mass. (34.24-4.5 g, n=10 in winter and 31.8:t:9.2 g, n= 19 in summer) was heavier than G. all enbyi (22.74-3.1 g, n=10 in winter and 22.84-5.9 g, Table 1.…”

Water and energy metabolism in free-living multi-mammate mice,Praomys natalensis, during summer

“…Perognathus /ormosus exhibits maximum metabolic rates of about 5,6 ml C~/g h during the late northern winter months of February and March, about double the rates found in summer (Mullen & Chew 1973). Similar seasonal influences on metabolic rates have been found in free-living Dipodomys merriami (Mullen 1971). Increased metabolic rates during winter probably result from increased thermogenesis during cold conditions.…”

“…The metabolic rates in free-living P. noto/ensis are intermediate to those that have been reported for other rodents (Table 1). The ratio of water to energy use in P. noto/ensis was 0,14, which is much higher than the values reported for desert rodents; 0,04 to 0,07 ml/k1 (Mullen 1971;Withers, Louw & Henschel 1980).…”

Energy Expenditure in Free‐Ranging Lizards

“…However, the ratio of cost of free living to maintenance cost is remarkably similar in these vertebrate groups: the ratios for lizards are 2.0 to 2.5 inS. occidentalis (Table 2) and 1.7 in Sauromalus obesus (Nagy and Shoemaker 1975); for birds, 2.8 in Progne subis (Utter and LeFebvre 1970) and 2.3 in Mimus polyglottos (Utter 1971); and for rodents (mean monthly averages), 2.8 in Perognathus formosus (Mullen 1970), 2.4 in Dipodomys merriami and 2.5 inDipodomys microps (Mullen 197Ia), and 3.5 in Peromyscus crinitus (Mullen 1971b). The primary reason for this discrepancy is that the free-living increment ratio is calculated from daily resting metabolism at both warm (diurnal) and cool (nocturnal) body temperatures for the lizards, so the denominator of this ratio is < 10--17% of endotherm levels stated above.…”

Field metabolic rates and water influxes of two sympatric Gerbillidae:Gerbillus allenbyi andG. pyramidum

“…Mass specific water influx in winter increased by 63.1% in G. allenbyi and by 62.5% in G. pyramidum when compared to their respective summer water influxes. For the two granivorous heteromyids, P.formosus (Mullen 1970) and D. merriami (Mullen 1971), these values were 58.7% and 56.6% of their predicted FMRs, respectively. FMRs of G. allenbyi and G. pyramidum were 69.3% and 74.5%, respectively, of those predicted for rodents of their body masses.…”

“…Means are ex-pressed+ SD and were compared using Student's t-test. Body mass (mb), total body water volume (TBW), water influx (WI), CO2 production (I2CO2) and field metabolic rates (FMR) of Gerbillus allenbyi and G. pyramidum in winter and summer Morris and Bradshaw (1981): WI (ml/day)=0.21 m b (g)0.9o c FMR predicted according to Nagy (1987): log FMR (kJ/day) = 1.022+ log m b (g) d Data from e Data from Mullen (1970) r Data from Mullen (1971) n = 33 in summer) in both winter and summer; intraspecific comparisons showed no significant seasonal differences in body mass. (34.24-4.5 g, n=10 in winter and 31.8:t:9.2 g, n= 19 in summer) was heavier than G. all enbyi (22.74-3.1 g, n=10 in winter and 22.84-5.9 g, Table 1.…”

Water and energy metabolism in free-living multi-mammate mice,Praomys natalensis, during summer

“…Perognathus /ormosus exhibits maximum metabolic rates of about 5,6 ml C~/g h during the late northern winter months of February and March, about double the rates found in summer (Mullen & Chew 1973). Similar seasonal influences on metabolic rates have been found in free-living Dipodomys merriami (Mullen 1971). Increased metabolic rates during winter probably result from increased thermogenesis during cold conditions.…”

“…The metabolic rates in free-living P. noto/ensis are intermediate to those that have been reported for other rodents (Table 1). The ratio of water to energy use in P. noto/ensis was 0,14, which is much higher than the values reported for desert rodents; 0,04 to 0,07 ml/k1 (Mullen 1971;Withers, Louw & Henschel 1980).…”

Energy Expenditure in Free‐Ranging Lizards

“…However, the ratio of cost of free living to maintenance cost is remarkably similar in these vertebrate groups: the ratios for lizards are 2.0 to 2.5 inS. occidentalis (Table 2) and 1.7 in Sauromalus obesus (Nagy and Shoemaker 1975); for birds, 2.8 in Progne subis (Utter and LeFebvre 1970) and 2.3 in Mimus polyglottos (Utter 1971); and for rodents (mean monthly averages), 2.8 in Perognathus formosus (Mullen 1970), 2.4 in Dipodomys merriami and 2.5 inDipodomys microps (Mullen 197Ia), and 3.5 in Peromyscus crinitus (Mullen 1971b). The primary reason for this discrepancy is that the free-living increment ratio is calculated from daily resting metabolism at both warm (diurnal) and cool (nocturnal) body temperatures for the lizards, so the denominator of this ratio is < 10--17% of endotherm levels stated above.…”

Field metabolic rates and water influxes of two sympatric Gerbillidae:Gerbillus allenbyi andG. pyramidum

“…Mass specific water influx in winter increased by 63.1% in G. allenbyi and by 62.5% in G. pyramidum when compared to their respective summer water influxes. For the two granivorous heteromyids, P.formosus (Mullen 1970) and D. merriami (Mullen 1971), these values were 58.7% and 56.6% of their predicted FMRs, respectively. FMRs of G. allenbyi and G. pyramidum were 69.3% and 74.5%, respectively, of those predicted for rodents of their body masses.…”

“…Means are ex-pressed+ SD and were compared using Student's t-test. Body mass (mb), total body water volume (TBW), water influx (WI), CO2 production (I2CO2) and field metabolic rates (FMR) of Gerbillus allenbyi and G. pyramidum in winter and summer Morris and Bradshaw (1981): WI (ml/day)=0.21 m b (g)0.9o c FMR predicted according to Nagy (1987): log FMR (kJ/day) = 1.022+ log m b (g) d Data from e Data from Mullen (1970) r Data from Mullen (1971) n = 33 in summer) in both winter and summer; intraspecific comparisons showed no significant seasonal differences in body mass. (34.24-4.5 g, n=10 in winter and 31.8:t:9.2 g, n= 19 in summer) was heavier than G. all enbyi (22.74-3.1 g, n=10 in winter and 22.84-5.9 g, Table 1.…”