The effect of branch diameter on primate gait sequence pattern

Abstract

Most mammals use lateral sequence gaits during quadrupedal locomotion, a pattern characterized by the touchdown of a forelimb directly following the ipsilateral hind limb in a given stride cycle. Primates, however, tend to use diagonal sequence (DS) gaits, whereby it is the touchdown of a contralateral forelimb that follows that of a given hind limb most closely in time. A number of scenarios have been offered to explain why primates favor DS gaits, most of them relating to the use of the arboreal habitat and, in particular, the exploitation of a narrow branch niche. This experimental study explores the potential explanation for the use of DS gaits by examining the relationship between branch diameter and gait patterns in 360 strides collected from six species of quadrupedal strepsirrhine primates on broad and narrow diameter supports. Gait sequence is quantified using limb phase, or the percentage of time during a stride cycle that a forelimb touchdown follows an ipsilateral hind limb touchdown. Although Loris, Nycticebus and Eulemur rubriventer individuals in this study did exhibit significantly lower locomotor velocities on narrower supports (P<0.01 in all three species), analyses of covariance showed no significant differences in limb phase values between broad and narrow diameter supports. Hence, results indicate surprisingly little evidence to suggest that alterations in gait sequence pattern provide a specific advantage for negotiating narrow supports.

Kinematics of quadrupedal locomotion in sugar gliders (Petaurus breviceps): effects of age and substrate size

“…This study contributes new data to a growing body of comparative literature addressing kinematic responses of (adult) small-bodied mammals to arboreal substrates, including those that are arboreally adapted with grasping extremities (Pridmore, 1994;Schmitt, 2003b;Schmitt and Lemelin, 2004;Delciellos and Vieira, 2006;Stevens, 2006;Delciellos and Vieira, 2007;Scheibe et al, 2007;Stevens, 2007;Nyakatura et al, 2008;Nyakatura and Heymann, 2010) and those that lack grasping capability and are predominantly terrestrial (Lemelin et al, 2003;Lammers and Biknevicius, 2004;Lammers, 2007;Lammers and Gauntner, 2008;Lammers, 2009;Schmidt and Fischer, 2010;Lammers and Zurcher, 2011). Much insight on L. J. Shapiro and J. W. Young arboreal adaptations has been gained from these studies, but this study is one of very few to provide ontogenetic kinematic data for mammals in an arboreal context (e.g.…”

“…Starting with the basic assumption that in arboreal mammals, stability is inversely related to relative body size, we hypothesized that sugar gliders would employ kinematic stabilizing mechanisms as body size increased relative to substrate diameter. Previous studies have tested for the effects of decreasing substrate diameter on quadrupedal kinematics in arboreal (Schmitt, 2003a;Delciellos and Vieira, 2006;Stevens, 2006;Delciellos and Vieira, 2007;Scheibe et al, 2007;Stevens, 2007;Lemelin and Cartmill, 2010) and non-arboreal (Lammers and Biknevicius, 2004; Lammers, 2007; Schmidt and Fischer, 2010) mammals, but these studies have been restricted to adult subjects at a given body size. By including both adults and juveniles in our sample, and by tracking kinematics longitudinally through ontogeny, our study has the added advantage of permitting the assessment of the effects of relative body (to substrate) size on locomotion across a more extensive range of body sizes within a single species (see also Young, 2009a).…”

“…Caluromys, Dromiciops, Trichosurus) share a preference for limb phases that correspond to DSDC walking gaits (Hildebrand, 1967;White, 1990;Pridmore, 1994;Lemelin et al, 2003;Reilly et al, 2010) [but see Shapiro and Young (Shapiro and Young, 2010) for discussion of Dromiciops]. DSDC walking, along with a complex of other kinematic features, has been associated with adaptation to a small branch arboreal niche (Larson, 1998;Cartmill et al, 2002;Lemelin et al, 2003;Cartmill et al, 2007), but the potential biomechanical advantage provided by DSDC for walking on small diameter substrates remains unclear (Stevens, 2006;Shapiro and Raichlen, 2007;Stevens, 2007;Wallace and Demes, 2008), and adult sugar gliders prefer LSDC walking, even on very narrow substrates (Shapiro and Young, 2010). In addition, infant primates have been shown to differ from adults in their gait preferences as a means to enhance stability or reduce limb interference (Hildebrand, 1967;Rose, 1977;Rollinson and Martin, 1981;Hurov, 1982;Vilensky and Gankiewicz, 1989;Nakano, 1996;Dunbar and Badam, 1998;Shapiro and Raichlen, 2005;Shapiro and Raichlen, 2006).…”

“…However, few studies have examined locomotor ontogeny in an environment where the 481 Locomotor ontogeny in sugar gliders natural diversity of substrates is represented. Field and especially lab-based studies of arboreal mammals have identified detailed kinematic or kinetic locomotor adjustments to substrate variation in adults (McClearn, 1992;Vilensky et al, 1994;Lemelin et al, 2003;Schmitt, 2003a;Schmitt and Hanna, 2004;Delciellos and Vieira, 2006;Stevens, 2006;Scheibe et al, 2007;Stevens, 2007;Nyakatura et al, 2008;Carlson and Demes, 2010;Nyakatura and Heymann, 2010;Schmidt and Fischer, 2010) but much less extensively from an ontogenetic perspective (but see Young, 2009a;Young, 2009b). In contrast, naturalistic studies of locomotor ontogeny in arboreal taxa (mainly primates) have mostly focused on ontogenetic shifts in locomotor and substrate preferences (e.g.…”

Üner Tan Syndrome: Review and Emergence of Human Quadrupedalism in Self-Organization, Attractors and Evolutionary Perspectives

“…However, no environmental mechanisms could be revealed to explain this particular footfall pattern in primates (Stevens, 2008;Cartmill et al, 2002;Shapiro & Raichlen, 2005;Stevens, 2003Stevens, , 2008. So, the question about the evolutionary mechanisms of the primate quadrupedal locomotion remained unresolved, at least concerning its benefits for balancing on the fine terminal branch settings, as Shapiro and Raichlen (2006) stated that there was "no consensus on why primates prefer this unusual type of gait."…”