2026-02-17 フランス国立科学研究センター(CNRS)
<関連情報>
- https://www.cnrs.fr/en/press/climb-down-trees-primates-adopt-upright-postures
- https://elifesciences.org/articles/108268
樹上性哺乳類の降下戦略の運動学と形態学的相関は、真霊長類の初期の直立姿勢を示唆している Kinematics and morphological correlates of descent strategies in arboreal mammals suggest early upright postures in euprimates
Severine LD Toussaint ,Dionisios Youlatos,John A Nyakatura
eLife Published:Feb 17, 2026
DOI:https://doi.org/10.7554/eLife.108268.3
Abstract
Ascending and descending sloping and vertical branches are critical for arboreal locomotion and likely played a major role in early primate evolution. While most studies have focused on ascent, descending behaviors also provide insight into the functional significance of arboreal adaptations. To test how descending vertical supports of varying diameters affect locomotor abilities, we quantified postural and kinematic features during descents and ascents on vertical supports in 21 eutherian and metatherian mammals and examined their relation to morphology. Primates showed greater variability in descent behaviors, using tail-first and side postures more often than other mammals, which predominantly descended head-first. Overall, animals adopted several kinematic adjustments to enhance stability during descent compared to ascent, including slower speeds, higher duty factors, and greater use of asymmetrical gaits. Additionally, vertical descent strategies reflected trade-offs among body mass, limb proportions, and head mass. Using a morphology-based model, we then inferred possible descent behaviors in 13 extinct euarchontoglires. Our results suggest that ancestral adaptations for vertical locomotion may have promoted frequent upright (head-up) postures in early primates.
