Most primates exhibit a trio of locomotor characteristics during horizontal walking that distinguishes them from most other mammals. These unusual primate features include a preponderance of diagonal sequence (DS) gaits, large forelimb protraction at the shoulder and higher vertical peak forces on the hindlimbs than the forelimbs (Demes et al., 1994; Kimura, 1985, 1992; Kimura et al., 1979; Larson, 1998; Larson and Demes, 2011; Larson et al., 2000; Schmitt, 1999, 2003a, 2012; Schmitt and Hanna, 2004; Schmitt and Lemelin, 2002, 2004). Though this suite of features is not universal to primates (e.g. the common marmoset, Callithrix jacchus, exhibits a preponderance of lateral sequence [LS] gaits [Schmitt, 2003a]) nor unique to primates (e.g. the woolly opossum, Caluromys philander, exhibits all three ‘primate-like’ gait features [Schmitt and Lemelin, 2002]), it is thought that these three biomechanical features are related to the earliest origins and diversifications of the primate clade.