Echolocating animals that forage in social groups can potentially benefit from eavesdropping on other group members, cooperative foraging or social defence, but may also face problems of acoustic interference and intra-group competition for prey. Here, we investigate these potential trade-offs of sociality for extreme deep-diving Blainville′s and Cuvier's beaked whales. These species perform highly synchronous group dives as a presumed predator-avoidance behaviour, but the benefits and costs of this on foraging have not been investigated. We show that group members could hear their companions for a median of at least 91% of the vocal foraging phase of their dives. This enables whales to coordinate their mean travel direction despite differing individual headings as they pursue prey on a minute-by-minute basis. While beaked whales coordinate their echolocation-based foraging periods tightly, individual click and buzz rates are both independent of the number of whales in the group. Thus, their foraging performance is not affected by intra-group competition or interference from group members, and they do not seem to capitalize directly on eavesdropping on the echoes produced by the echolocation clicks of their companions. We conclude that the close diving and vocal synchronization of beaked whale groups that quantitatively reduces predation risk has little impact on foraging performance.

中文翻译：

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深潜喙鲸一起潜水但觅食分开

在社会群体中觅食的回声定位动物可能会从窃听其他群体成员、合作觅食或社会防御中受益，但也可能面临声干扰和群体内猎物竞争的问题。在这里，我们调查了极端深潜的 Blainville 和 Cuvier 喙鲸的这些潜在的社会性权衡。这些物种进行高度同步的群体潜水，作为一种假定的捕食者回避行为，但尚未研究这种行为对觅食的好处和成本。我们表明，在潜水的声音觅食阶段，小组成员可以听到他们的同伴至少 91% 的声音。这使得鲸鱼能够在每分钟追逐猎物时协调它们的平均行进方向，尽管它们的个体航向不同。虽然喙鲸紧密协调它们基于回声定位的觅食期，但个体点击率和嗡嗡声率都与群体中鲸鱼的数量无关。因此，它们的觅食性能不受群体内竞争或群体成员干扰的影响，而且它们似乎没有直接利用窃听同伴回声定位点击产生的回声。我们得出结论，喙鲸群的近距离潜水和声音同步在数量上降低了捕食风险，对觅食性能的影响很小。他们似乎并没有直接利用窃听同伴的回声定位点击产生的回声。我们得出结论，喙鲸群的近距离潜水和声音同步在数量上降低了捕食风险，对觅食性能的影响很小。他们似乎并没有直接利用窃听同伴的回声定位点击产生的回声。我们得出结论，喙鲸群的近距离潜水和声音同步在数量上降低了捕食风险，对觅食性能的影响很小。