Brudzynski S M, Bihari F, Ociepa D, Fu X W
Department of Clinical Neurological Sciences, University of Western Ontario, London, Canada.
Physiol Behav. 1993 Aug;54(2):215-21. doi: 10.1016/0031-9384(93)90102-l.
There is a remarkable variation in the length of single ultrasonic calls emitted by adult rats. The duration of calls is likely to convey information for conspecifics. The goal of the present study was to analyze 22 kHz calls emitted by naive laboratory rats in response to contact with the human hand and to measure their acoustic features, with a particular emphasis on call duration. Repeated hand touch applied to the nape of the neck of rats induced ultrasonic calls, 97.4% of which were within the range of 20-29 kHz and 2.6% of which were within 44-67 kHz. Distribution of duration of 6765 calls revealed two subpopulations of 22 kHz calls: 20-300 ms calls with its peak at 150 ms and calls above 310 ms with highest values at approximately 500-600 ms without a clear peak. These two call populations were referred to as short and long calls, respectively. The short and the long vocalizations contained 80% and 100% of calls within the range of the 22 kHz frequency, respectively. The findings indicated that, in the situation studied, the 22 kHz vocalization of adult rats consists of two distinguishable subpopulation of calls: short and long with the boundary between them at 300 ms.
成年大鼠发出的单次超声波叫声的时长存在显著差异。叫声的时长可能会向同种个体传达信息。本研究的目的是分析未经训练的实验大鼠在与人类手部接触时发出的22千赫兹叫声，并测量其声学特征，尤其着重于叫声时长。对大鼠颈部后方反复进行手部触摸会诱发超声波叫声，其中97.4%的叫声频率在20 - 29千赫兹范围内，2.6%的叫声频率在44 - 67千赫兹范围内。6765次叫声的时长分布显示，22千赫兹的叫声可分为两个亚群：时长为20 - 300毫秒且峰值在150毫秒的叫声，以及时长超过310毫秒且最高值在约500 - 600毫秒且无明显峰值的叫声。这两个叫声群体分别被称为短叫声和长叫声。短叫声和长叫声中，频率在22千赫兹范围内的叫声分别占80%和100%。研究结果表明，在所研究的情境中，成年大鼠发出的22千赫兹叫声由两个可区分的亚群组成：短叫声和长叫声，它们之间的界限为300毫秒。
