Figure 2: Preferred gait kinematics in terrestrial vertebrates.

Log-log plots of (a) duty factor (DF), (b) stride frequency (f_stride, Hz), (c) stance duration (t_stance, s) and (d) swing duration (t_swing, s) against body mass (M_b, kg). The dotted line in (b) represents the line of best fit through the only comparable data for African mammals³. The dashed line in (d) represents the natural pendular period for mammalian limbs²¹. The lines fitted through the data are derived from the ANCOVA output and are: DF = 0.62 M_b^0.02 (mammals), DF = 0.67 M_b^0.03 (birds); f_stride = 1.62 M_b^−0.15 (mammals), f_stride = 1.21 M_b^−0.15 (birds); t_stance = 0.38 M_b^0.17 (mammals), t_stance = 0.56 M_b^0.17 (birds); t_swing = 0.25 M_b^0.11 (mammals), t_swing = 0.26 M_b^0.11 (birds). More details of the analyses can be found in Supplementary Table S2.