Data from: On the interplay among ambient temperature, basal metabolic rate and body mass

One of the most generalized conclusions arising from studies analyzing the
ecological variation of energy metabolism in endotherms is the apparent
negative correlation between ambient temperature and mass-independent
basal metabolic rate (residual BMR). As a consequence, ambient temperature
has been considered the most important external factor driving the
evolution of residual BMR. It is not clear, however, if this relationship
is size dependent, and artifacts such as the biased sampling of body
masses in physiological data sets could cause us to overstate the ubiquity
of the relationship. Accordingly, here we used published data on body mass
(mb), BMR, and annual mean temperature (Tmean) for 458 mammal species
(and/or subspecies) to examine the size-dependence of the relationship
between temperature and BMR. We found a significant interaction between mb
and Tmean, such that the effect of Tmean on residual BMR decreases as a
function of mb. In line with this, the amount of residual variance in BMR
explained by Tmean decreased with mb, from 20 - 30% at body sizes <
100 g to almost zero at body size > 1,000 g. These data suggest
that our current understanding of the importance of broad-scale variation
in ambient temperature as a driver of metabolic evolution in endotherms
probably is affected by the large number of small species in both nature
and physiological datasets.