Begall Sabine, Burda Hynek, Schneider Bianca
Department of General Zoology, Faculty of Biosciences (FB9), University of Duisburg-Essen, 45117 Essen, Germany.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2004 Nov;190(11):963-9. doi: 10.1007/s00359-004-0552-1. Epub 2004 Aug 18.
Learning curves and behavioural audiograms of subterranean, socially living coruros (Spalacopus cyanus) were obtained using a positive reinforcement conditioning procedure. The individually varying audiograms revealed best hearing at frequencies between 1.25 and 1.6 kHz, which corresponds with the common pattern established in subterranean rodents studied so far. However, the broad hearing range covering frequencies at least between 0.25 and 20 kHz coupled with the high sensitivity (average minimum 7 dB) that is found in coruros are atypical features for audiograms of subterranean rodents, which usually show restricted high-frequency hearing ranges and very poor sensitivity. Hearing at low frequencies (peaks at frequencies <1 kHz), which may be related to sound transmission in underground burrows, and high sensitivity at 1.25/1.6 kHz are discussed in relation to vocalization. In addition to these peaks, a third peak at 8 kHz--probably a plesiomorphic feature of mammals--may be of significance in aboveground communication.
利用正强化条件反射程序，获得了地下群居豚鼠（Spalacopus cyanus）的学习曲线和行为听力图。个体差异的听力图显示，在1.25至1.6千赫兹的频率范围内听力最佳，这与迄今为止对地下啮齿动物所确立的常见模式相符。然而，豚鼠的听力范围很广，至少覆盖0.25至20千赫兹的频率，且具有高灵敏度（平均最低7分贝），这对于地下啮齿动物的听力图来说是不典型的特征，地下啮齿动物通常表现出有限的高频听力范围和非常低的灵敏度。讨论了低频听力（频率<1千赫兹时出现峰值）可能与地下洞穴中的声音传播有关，以及在1.25/1.6千赫兹时的高灵敏度与发声的关系。除了这些峰值外，8千赫兹处的第三个峰值——可能是哺乳动物的一个原始特征——可能在地面交流中具有重要意义。
