A user's guide for the quantitative analysis of substrate characteristics and locomotor kinematics in free‐ranging primates

Abstract

Ultimately, these methods will help researchers identify more precisely how primate gait kinematics respond to the complexity of arboreal habitats, furthering our understanding of the adaptive context in which primate quadrupedalism evolved.

Effects of substrate and phylogeny on quadrupedal gait in free‐ranging platyrrhines

“…We collected data opportunistically and attempted to film individuals moving quadrupedally in different forest strata and on substrates varying in diameter, orientation angle, and type (i.e., tree branch, palm frond, liana, or bamboo). We used modified GoPro Hero 5 cameras (GoPro, Inc., San Mateo, CA) equipped with a Back‐Bone Ribcage H5Pro (Back‐Bone, Ottawa, Ontario, Canada) and C mount Fujinon HD 8–80 mm Vari‐Focal CCTV lenses (Fujifilm, Tokyo, Japan) (Dunham et al, ). We filmed at 1080 p resolution and 120 fps which provided a sufficient footage for recording limb touchdown and liftoff events (Dunham et al, ).…”

“…We remotely quantified substrate diameter using the distance meter photogrammetric technique (Dunham et al, ). This method is predicated on collecting accurate measurements of the distance between the target object plane (i.e., a plane‐oriented perpendicular to the optical axis and containing all target landmarks) and the camera lens (Galbany et al, ).…”

“…Finally, pixel pitch (i.e., the distance between the centers of neighboring pixels, typically reported in μm) is an intrinsic property of the camera sensor. Our previous research has demonstrated that the distance meter photogrammetric technique is capable of measuring the diameter of cylindrical substrates to an accuracy of ±1.5 mm (Dunham et al, ). We used a forestry‐grade range finder (TruPulse 360R, Laser Technology Incorporated, Centennial, CO) to quantify substrate orientation angle (Dunham et al, ).…”

“…Our previous research has demonstrated that the distance meter photogrammetric technique is capable of measuring the diameter of cylindrical substrates to an accuracy of ±1.5 mm (Dunham et al, ). We used a forestry‐grade range finder (TruPulse 360R, Laser Technology Incorporated, Centennial, CO) to quantify substrate orientation angle (Dunham et al, ). Our previous research found that the rangefinder recorded substrate orientation to an accuracy of ±2.5° (Dunham et al, ).…”

“…Due to prohibitory costs and other limitations, laboratory studies of primate locomotion are also often plagued by small sample sizes (i.e., usually a few individuals representing a single species). Recent technological and methodological developments now allow researchers to more easily collect kinematic data on free‐ranging animals and to remotely quantify important aspects of their environments (McNamara, Dunham, Shapiro, & Young, in review; Dunham, McNamara, Shapiro, Hieronymus, & Young, ; Hirasaki, Malaivijitnond, & Hamada, ; Nyakatura & Heymann, ; Shapiro, Young, & Souther, ; Stevens, Ratsimbazafy, & Ralainasolo, ; Youlatos & Gasc, ), permitting more relevant tests of locomotor performance and adaptation (Gilman & Irschick, ; Irschick & Garland, ).…”