Table 2.

Analyses of covariance for O2max and daily O2mean testing for effects of acclimation, sex and different subordinate traits, controlling for differences in carcass mass (as a surrogate for body size, see Materials and methods)

O2maxO2mean
Initial model (IM)d.f.C/WM/FF changePC/WM/FF changeP
   Acclimation1,3582.582 <0.0001 67.961 <0.0001
   Sex1,356.018 0.019 0.1290.722
   Carcass mass1,351.391.0913.520 0.001 [+] 1.900.970.0990.755 [+]
IM + heart1,341.281.099.222 0.005 [+] 1.610.976.789 0.014 [+]
IM + lungsa1,331.371.075.441 0.026 [+] 1.810.9211.763 0.002 [+]
IM + digestive tract1,341.341.132.9240.096 [+]1.731.053.7150.062 [+]
IM + spleen1,341.401.090.8610.360 [+]1.960.982.8480.101 [+]
IM + kidney1,341.331.081.9290.174 [+]1.610.966.249 0.017 [+]
IM + liver1,341.351.091.9900.167 [+]1.690.995.439 0.026 [+]
IM + absolute body fat1,341.351.0411.426 0.002 [–] 1.800.898.671 0.006 [–]
IM + relative body fat1,341.381.0711.053 0.002 [–] 1.870.954.974 0.032 [–]
IM + hematocrit1,341.391.090.0230.881 [+]1.930.980.3370.566 [–]
  • Signs of partial regression coefficients for carcass mass and subordinate traits are in brackets. The magnitude of acclimation and sex effects is shown with ratios between adjusted means from cold- vs warm-acclimated animals (C/W) and males vs females (M/F). Values in bold are statistically significant after accounting for false discovery rates (Materials and methods)

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