Young B A
Department of Anatomy, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
J Exp Zool. 1991 Dec;260(3):275-87. doi: 10.1002/jez.1402600302.
A bioacoustic analysis is conducted on the defensive sounds produced by 21 species of snakes. The "typical" snake hiss is described as having a broad-frequency span (from roughly 3,000 to 13,000 Hertz) and a dominant frequency near 7,500 Hertz. The "growl" of the king cobra (Ophiophagus hannah) differs from the "typical" snake hiss in consisting solely of frequencies below 2,500 Hertz, with a dominant frequency near 600 Hertz. Structural analysis of the upper respiratory tract of O. hannah suggests that the "growl" is produced by tracheal diverticula functioning as low-frequency resonating chambers. This hypothesis is supported in several ways. An acoustic analysis of a mechanical model of the trachea demonstrates the potential for these diverticula to produce resonance effects. A "growl" also occurs in the mangrove ratsnake (Gonyosoma oxycephalum), a species that also has tracheal diverticula. Flushing the respiratory tract of G. oxycephalum with helium produces a shift of over 1,000 Hertz in the "growl," a shift that is indicative of a resonance effect.
对21种蛇发出的防御性声音进行了生物声学分析。“典型”的蛇嘶嘶声被描述为具有较宽的频率范围（大致从3000赫兹到13000赫兹），且主频接近7500赫兹。眼镜王蛇（眼镜王蛇属）的“咆哮”与“典型”的蛇嘶嘶声不同，它仅由低于2500赫兹的频率组成，主频接近600赫兹。对眼镜王蛇上呼吸道的结构分析表明，“咆哮”是由作为低频共鸣腔的气管憩室产生的。这一假设得到了多方面的支持。对气管力学模型的声学分析表明，这些憩室具有产生共振效应的潜力。红树林鼠蛇（尖吻蛇属）也会发出“咆哮”声，该物种同样具有气管憩室。用氦气冲洗尖吻蛇的呼吸道会使“咆哮”声的频率发生超过1000赫兹的偏移，这种偏移表明存在共振效应。
