Table 1.

Effects of sex, acclimation and body mass on morphological and physiological traits of Peromyscus maniculatus

Cold acclimated Warm acclimated Ratio
MalesFemalesMalesFemalesC/WM/FPacclimationPsexPbody mass
N 1010109
Body mass (g)23.17±0.8024.33±0.8024.60±0.8325.75±0.800.940.950.1350.226
Carcass dry mass (g)6.46 [5.97–7.00]6.55 [6.06–7.07]6.86 [6.34–7.43]6.95 [6.42–7.53]0.940.990.1930.776 <0.0001
O2max (ml min–1)9.399±0.2088.670±0.2016.878±0.2086.149±0.2081.391.07 <0.0001 0.004 <0.0001
O2mean (ml min–1)4.241±0.1894.239±0.1832.157±0.1892.155±0.1891.971.00 <0.0001 0.993 0.030
Heart dry mass (g)0.0495±0.00180.0483±0.00180.0365±0.00180.0353±0.00181.361.03 <0.0001 0.583 0.0003
Lung dry mass (g)a0.0398±0.00120.0381±0.00120.0376±0.00120.0359±0.00121.091.050.1250.229 0.001
Stomach dry mass (g)0.1086±0.00460.1257±0.00450.0958±0.00460.1128±0.00461.130.86 0.022 0.003 0.011
Small intestine dry mass (g)0.2244±0.01330.2632±0.01290.1655±0.01330.2043±0.01331.320.83 0.001 0.016 0.017
Large intestine dry mass (g)0.0489±0.00320.0594±0.00310.0372±0.00320.0477±0.00321.280.80 0.004 0.008 0.003
Cecum dry mass (g)0.0598±0.00300.0695±0.00290.0444±0.00300.0542±0.00301.320.84 <0.0001 0.007 0.006
Spleen dry mass (g)0.0100±0.00100.0098±0.00100.0115±0.00110.0113±0.00100.871.020.2360.896 0.002
Kidney dry mass (g)0.1047±0.00320.1003±0.00310.0806±0.00320.0762±0.00321.311.05 <0.0001 0.235 0.0004
Liver dry mass (g)0.4515±0.01190.4559±0.01150.3839±0.01190.3883±0.01191.170.99 <0.0001 0.750 <0.0001
Absolute body fat (g)1.683±0.2402.354±0.2382.406±0.2463.077±0.2400.740.75 0.014 0.021 <0.0001
Relative body fat (%)7.12±0.919.24±0.919.60±0.9411.73±0.910.770.80 0.026 0.053 <0.0001
Hematocrit (%)50.90±0.8649.70±0.8648.94±0.8647.75±0.861.041.020.0620.2420.463
  • We report adjusted means ± s.e. for a deer mouse of 24.5 g, or 95% confidence intervals between brackets for carcass dry mass back-transformed from log10 values. Ratios were estimated from acclimation or sex-adjusted means controlling for all additional factors and covariates (acclimation × sex interaction not included; see Materials and methods). Values in bold are significant at α=0.05

    C, cold acclimated; W, warm acclimated; M, males; F, females

  • a One cold-acclimated female was removed from the analyses because of measurement problems