Datasets and R code for "Ecological and phylogenetic influences on limb joint kinematics in wild primates"

R code and datasets relating to "Ecological and phylogenetic influences on limb joint kinematics in wild primates". Arboreal locomotion is precarious and places multiple challenges upon stability when animals are moving over narrow, compliant, angled, and disparate supports. Previous studies have shown that captive primates often respond to narrower and steeper supports by flexing limb joints (lowering the center of mass) and adopting a compliant gait, marked by increased proximal joint excursions and increased yield at distal joints (flattening the center of mass trajectory). In this study we tested whether these same kinematic responses to narrow and steep supports are adopted by wild primates freely ranging over a variety of supports in their natural habitats. Our wild primate sample included five species of platyrrhines, five species of catarrhines, and four species of strepsirrhines. We used modified GoPro cameras to record high speed videos of wild primate locomotion and remote measurement to precisely quantify the diameter, orientation, and compliance of their natural locomotor supports. Video images were imported into ImageJ to measure the angular kinematics of forelimb and hindlimb joints during quadrupedal locomotion on a variety of arboreal supports. Statistical models were fitted to infer associations between joint posture and support diameter/inclination. Additionally, we disentangled the influence of phylogeny and substrate using variation partitioning and redundancy analysis. Our results partially confirm previous kinematic studies of captive primates and suggest variation in support orientation, more than diameter, influences quadrupedal gait kinematics; in particular shoulder excursion and knee yield increase on declines and hip excursion increases on inclines . Phylogenetic relatedness explained more variation in the data than substrate properties. This suggests that when moving in their natural environment, primates either prospectively choose relatively ‘safe’ substrates for locomotion, or that they possess other locomotor adaptations independent of limb joint kinematics per se to overcome the challenges of the precarious arboreal environment.