Johnson M, Hickmott L S, Aguilar Soto N, Madsen P T
Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
Proc Biol Sci. 2008 Jan 22;275(1631):133-9. doi: 10.1098/rspb.2007.1190.
Toothed whales echolocating in the wild generate clicks with low repetition rates to locate prey but then produce rapid sequences of clicks, called buzzes, when attempting to capture prey. However, little is known about the factors that determine clicking rates or how prey type and behaviour influence echolocation-based foraging. Here we study Blainville's beaked whales foraging in deep water using a multi-sensor DTAG that records both outgoing echolocation clicks and echoes returning from mesopelagic prey. We demonstrate that the clicking rate at the beginning of buzzes is related to the distance between whale and prey, supporting the presumption that whales focus on a specific prey target during the buzz. One whale showed a bimodal relationship between target range and clicking rate producing abnormally slow buzz clicks while attempting to capture large echoic targets, probably schooling prey, with echo duration indicating a school diameter of up to 4.3m. These targets were only found when the whale performed tight circling manoeuvres spending up to five times longer in water volumes with large targets than with small targets. The result indicates that toothed whales in the wild can adjust their echolocation behaviour and movement for capture of different prey on the basis of structural echo information.
野生环境中的齿鲸在定位猎物时会发出低重复率的咔嗒声，但在试图捕获猎物时会产生快速的咔嗒声序列，即所谓的“嗡嗡声”。然而，对于决定咔嗒声频率的因素，以及猎物类型和行为如何影响基于回声定位的觅食行为，我们知之甚少。在这里，我们使用多传感器DTAG研究了在深水中觅食的布兰氏喙鲸，该传感器记录了发出的回声定位咔嗒声和从中层猎物返回的回声。我们证明，嗡嗡声开始时的咔嗒声频率与鲸鱼和猎物之间的距离有关，这支持了鲸鱼在嗡嗡声期间专注于特定猎物目标的推测。一头鲸鱼在目标距离和咔嗒声频率之间呈现出双峰关系，在试图捕获大型回声目标（可能是群体猎物）时，发出异常缓慢的嗡嗡声咔嗒声，回声持续时间表明群体直径可达4.3米。这些目标只有在鲸鱼进行紧密盘旋动作时才能发现，在有大型目标的水体中停留的时间是有小型目标水体的五倍。结果表明，野生齿鲸可以根据结构回声信息调整其回声定位行为和动作，以捕获不同的猎物。
