Fig. 7.

Pitch rotations during walks, trots, and canters of the head vs the neck (A), the neck vs the trunk (B) and the head vs the trunk (D) relative to space, and of the head relative to the neck vs the neck relative to the trunk (C). Pitch rotations of the head vs the trunk during overground walks and slow gallops in two monkey species – bonnet macaques (Macaca radiata) and hanuman langurs (Semnopithecus entellus) – in the wild (E) are presented for comparison with graph D. Horizontal and vertical broken lines indicate 20 deg. threshold for stabilization. Monkey data (E) are from Dunbar and colleagues (Dunbar et al. 2004) and the graph is modified from Dunbar (Dunbar, 2004).