The relationship between the mass specific cost of transport and body mass.

<p>Open symbols represent metabolic energy (<i>E</i>_met), closed symbols mechanical energy (<i>E</i>_{mech, CM}), triangles are species with <1 kg body masses <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0006927#pone.0006927-Heglund1" target="_blank">[3]</a> and squares species>1 kg <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0006927#pone.0006927-Cavagna1" target="_blank">[6]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0006927#pone.0006927-Cavagna2" target="_blank">[7]</a>. Data for <i>Macropus rufus</i> are labelled with <i>mr</i> symbols. Individual trend-lines calculated from the ANCOVA coefficient tables are for the <i>E</i>_{mech, CM} data; <i>y</i> = 1.17<i>x</i>^−0.03 (all data grouped), <i>y</i> = 2.06<i>x</i>^−0.22 (species>1 kg) and <i>y</i> = 0.391<i>x</i>^−0.46 (species<1 kg). For the <i>E</i>_met data the trend-lines are <i>y</i> = 11.38<i>x</i>^−0.30, <i>y</i> = 8.38<i>x</i>^−0.19 and <i>y</i> = 6.55<i>x</i>^−0.53 for all data grouped, species>1 kg and species<1 kg respectively.