College of Marine Science, University of South Florida, 140 7th Avenue South, St Petersburg, Florida 33701, USA.
J Acoust Soc Am. 2010 Jan;127(1):568-78. doi: 10.1121/1.3257202.
Trained odontocetes appear to have good control over the timing (pulse rate) of their echolocation clicks; however, there is comparatively little information about how free-ranging odontocetes modify their echolocation in relation to their environment. This study investigates echolocation pulse rate in 14 groups of free-ranging bottlenose dolphins (Tursiops truncatus) at a variety of depths (2.4-30.1 m) in the Gulf of Mexico. Linear regression models indicated a significant decrease in mean pulse rate with mean water depth. Pulse rates for most groups were multi-modal. Distance to target estimates were as high as 91.8 m, assuming that echolocation was produced at a maximal rate for the target distance. A 5.29-ms processing lag time was necessary to explain the pulse rate modes observed. Although echolocation is likely reverberation limited, these results support the hypotheses that free-ranging bottlenose dolphins in this area are adapting their echolocation signals for a variety of target detection and ranging purposes, and that the target distance is a function of water depth.
经训练的齿鲸似乎能够很好地控制回声定位咔哒声的时间（脉冲率）；然而，关于自由生活的齿鲸如何根据环境改变其回声定位，相关信息相对较少。本研究调查了墨西哥湾 14 组自由生活的宽吻海豚（Tursiops truncatus）在各种深度（2.4-30.1 米）下的回声定位脉冲率。线性回归模型表明，平均脉冲率与平均水深呈显著下降趋势。大多数群体的脉冲率呈多峰模式。假设回声定位是在目标距离的最大速率下产生的，目标估计距离高达 91.8 米。需要 5.29 毫秒的处理延迟时间来解释观察到的脉冲率模式。尽管回声定位可能受到混响限制，但这些结果支持以下假设：该地区的自由生活宽吻海豚正在根据各种目标检测和测距目的调整其回声定位信号，并且目标距离是水深的函数。
