The Capture Shift Hypothesis: Functional Decoupling of Capture and Feeding as a Framework for Coordinated Primate Evolution

Sangguk Han

The evolutionary origin of defining primate characteristics has been explained through ecological, behavioral, and dietary hypotheses, yet a broader question remains: why did multiple traits evolve in a broadly coordinated manner? This study proposes the Capture Shift Hypothesis (CSH), a testable conceptual framework in which prey capture was progressively redistributed from the oral apparatus to the forelimbs. This behavioral transition is hypothesized to have reorganized functional relationships among anatomical systems by reducing the shared dependence of prey acquisition and food processing on the same structures. The resulting functional decoupling may have partially relaxed capture-related constraints, allowing craniofacial morphology, dentition, manual specialization, sensory organization, cervical biomechanics, and neural systems to respond more independently to their respective selective pressures while evolving within a shared functional context. CSH does not replace established hypotheses concerning arboreality, visual predation, dietary adaptation, or social and cognitive evolution. Rather, it operates at a complementary explanatory level by asking whether a common change in functional organization helped coordinate otherwise distinct adaptive responses. Comparative anatomy, functional morphology, biomechanics, developmental biology, paleontology, and phylogenetic analysis provide evidence consistent with the biological plausibility of the framework, although no current observation directly demonstrates the proposed historical sequence. CSH therefore generates ten explicit predictions concerning temporal sequence, functional organization, morphological diversification, evolutionary modularity, sensorimotor integration, cross-lineage generality, and the fossil record. Its scientific value will depend on whether these predictions can support, refine, or falsify the proposed framework.