Fig. 7. (A) Manus and pes placement about the arboreal trackway. Location of the center of pressure of each foot is drawn to scale relative to branch cross-sectional shape. (B) Representative required coefficient of friction data from M. domestica on the arboreal trackway (1.10 m s^–1). High values occur at the foot touchdown and again at the end of the step. The broken line indicates the median value for this record (0.528). (C) Median required coefficient of friction for fore limbs and hind limbs on horizontal terrestrial and arboreal substrates. Ellipses are used to make each group more visible, and are calculated as in Fig. 5.