Start Date
April 2026
Location
2nd floor - Library
Abstract
Primate limb proportions are closely associated with locomotor behavior and environmental adaptation. Arboreal and terrestrial primates exhibit distinct skeletal morphologies that reflect the mechanical demands of their primary modes of movement. This study examined interspecific differences in limb proportions among primates with varying locomotor strategies. The species analyzed included Gorilla gorilla (gorilla), Pongo (orangutan), Ateles (spider monkey), and Alouatta (howler monkey). Measurements of major limb bones: the humerus, radius, femur, and tibia were collected from digital images and quantified using ImageJ software. Limb indices (intermembral, brachial, and crural) were calculated and compared using analysis of variance (ANOVA), revealing significant differences among species (p < 0.05). Orangutans exhibited the highest intermembral index, indicating relatively elongated forelimbs, whereas gorillas showed intermediate values. Spider monkeys and howler monkeys displayed more balanced limb proportions. These results suggest that variation in limb proportions reflects species‑specific locomotor behaviors, with elongated forelimbs associated with suspensory locomotion and more proportional limb lengths associated with quadrupedal movement.
Limb Proportions and Locomotor Behavior in Primates
2nd floor - Library
Primate limb proportions are closely associated with locomotor behavior and environmental adaptation. Arboreal and terrestrial primates exhibit distinct skeletal morphologies that reflect the mechanical demands of their primary modes of movement. This study examined interspecific differences in limb proportions among primates with varying locomotor strategies. The species analyzed included Gorilla gorilla (gorilla), Pongo (orangutan), Ateles (spider monkey), and Alouatta (howler monkey). Measurements of major limb bones: the humerus, radius, femur, and tibia were collected from digital images and quantified using ImageJ software. Limb indices (intermembral, brachial, and crural) were calculated and compared using analysis of variance (ANOVA), revealing significant differences among species (p < 0.05). Orangutans exhibited the highest intermembral index, indicating relatively elongated forelimbs, whereas gorillas showed intermediate values. Spider monkeys and howler monkeys displayed more balanced limb proportions. These results suggest that variation in limb proportions reflects species‑specific locomotor behaviors, with elongated forelimbs associated with suspensory locomotion and more proportional limb lengths associated with quadrupedal movement.
