Mobile larynx in Mongolian gazelle: Retraction of the larynx during rutting barks in male Mongolian gazelle (Procapra gutturosa Pallas, 1777) |
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Authors: | Roland Frey Alban Gebler Kirk A. Olson Daria Odonkhuu Guido Fritsch Nyamsuren Batsaikhan Ingo W. Stuermer |
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Affiliation: | 1. Leibniz Institute for Zoo and Wildlife Research (IZW), Berlin, Germany;2. Institute for Theoretical Biology, Humboldt University, Berlin, Germany;3. Wildlife Conservation Society, 2300 Southern Boulevard, Bronx, New York 10460;4. Department of Natural Resources Conservation, 160 Holdsworth Way, University of Massachusetts, Amherst, Massachusetts 01003‐9825;5. Wildlife Conservation Society, Mongolia Program, Amar Street‐3, Internom Bookstore Building, 3rd floor, Ulaanbaatar, Mongolia;6. Clinic for Small Animals, Oertzenweg, Berlin, Germany;7. Faculty of Biology, Department of Zoology, National University of Mongolia, Ulaanbaatar, Mongolia;8. Sensory Developmental Research Group, Department of Phoniatrics and Pedaudiology, Georg‐August‐University, Goettingen, Germany |
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Abstract: | This study provides the first evidence of pronounced temporary laryngeal descent in a bovid species. An elaborate acoustic display is prominent in male courtship behavior of polygynous Mongolian gazelle. During rut, rounding up of females is accompanied by continuous head‐up barking by dominant males. Throughout the rut their evolutionarily enlarged larynx descends to a low mid‐neck resting position. In the course of each bark the larynx is additionally retracted toward the sternum by 30% of the resting vocal tract length. A geometric model of active larynx movements was constructed by combining results of video documentation, dissection, skeletonization, and behavioral observation. The considerable distance between resting position and maximal laryngeal descent suggests a backward tilting of the hyoid apparatus and an extension of the thyrohyoid connection during the retraction phase. Return to the resting position is effected by strap muscles and by the elastic recoil of the pharynx and the thyrohyoid connection. An intrapharyngeal inflation of the peculiar palatinal pharyngeal pouch of adult males is inferred from a short‐time expansion of the ventral neck region rostral to the laryngeal prominence. The neck of adult dominant males is accentuated by long gray guard hairs during the rut. The passive swinging of the heavy larynx of adult males during locomotion gives the impression of a handicap imposed on rutting males. Apparently, this disadvantage becomes outweighed by the profits for reproductive success. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc. |
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Keywords: | vocal tract comparative anatomy laryngeal sound production evolutionary morphology rutting behavior |
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