2026/04/26 by Maja Mielke, Falk Mielke, Nicholas W. Gladman +4 · 1 voice
Biochemistry, Genetics and Molecular Biology · Earth and Planetary Sciences · Psychology · #Animal Vocal Communication and Behavior #Paleontology and Evolutionary Biology #Primate Behavior and Ecology
paper · doi:10.64898/2026.04.22.720076
openalex publication_date 2026/04/26 · openalex created_date 2026/04/27 · openalex updated_date 2026/07/22
Abstract Dexterous manipulation of objects relies on precise coordination between anatomical elements. In seed-eating birds, seeds are manipulated and dehusked using both the beak and tongue, but the functional roles and coordination of these structures remain unresolved. Here, we quantified the 3D movements of the upper beak, lower beak, tongue, and seed in a hard-biting and a weak-biting songbird species using X-ray Reconstruction of Moving Morphology (XROMM) and measured contractile properties of their primary jaw muscles. We show that the tongue serves as the main tool for seed rotation, transport, and stabilization. Multi-dimensional, high-frequency movements of the upper and lower beaks reveal that efficient seed processing depends on high mobility of the kinetic avian skull. Strong and weak biters differ in feeding kinematics and jaw muscle speeds, suggesting ecological specialization of cranial mechanics. The complexity, precision, and tight coordination of beak and tongue motions show that the avian cranium rivals the dexterity of the primate hand despite limited degrees of freedom.