Center for Conservation Biology, Stanford University, Stanford, CA, United States of America.
Center for the Environment, Harvard University, Cambridge, MA, United States of America.
PeerJ. 2024 Jul 22;12:e17767. doi: 10.7717/peerj.17767. eCollection 2024.
Group-living animals engage in coordinated vocalizations to depart from a location as a group, and often, to come to a consensus about the direction of movement. Here, we document for the first time, the use of coordinated vocalizations, the "let's go" rumble, in wild male African elephant group departures from a waterhole. We recorded vocalizations and collected behavioral data as known individuals engaged in these vocal bouts during June-July field seasons in 2005, 2007, 2011, and 2017 at Mushara waterhole within Etosha National Park, Namibia. During departure events, we documented which individuals were involved in the calls, the signature structure of each individual's calls, as well as the ordering of callers, the social status of the callers, and those who initiated departure. The "let's go" rumble was previously described in tight-knit family groups to keep the family together during coordinated departures. Male elephants are described as living in loose social groups, making this finding particularly striking. We found that this vocal coordination occurs in groups of closely associated, highly bonded individuals and rarely occurs between looser associates. The three individuals most likely to initiate the "let's go" rumble bouts were all highly socially integrated, and one of these individuals was also the most dominant overall. This finding suggests that more socially integrated individuals might be more likely to initiate, or lead, a close group of associates in the context of leaving the waterhole, just as a high-ranking female would do in a family group. The fact that many individuals were involved in the vocal bouts, and that departure periods could be shorter, longer, or the same amount of time as pre-departure periods, all suggest that there is consensus with regard to the act of leaving, even though the event was triggered by a lead individual.
群居动物会发出协调的叫声，集体离开一个地方，通常还会就移动方向达成一致。在这里，我们首次记录了协调的叫声——“出发”隆隆声，在纳米比亚埃托沙国家公园 Mushara 水坑处的野生雄性非洲象群体离开水坑时使用。在 2005 年、2007 年、2011 年和 2017 年 6 月至 7 月的野外季节，我们记录了已知个体在这些叫声中的叫声，并收集了行为数据。在出发事件中，我们记录了参与呼叫的个体、每个个体呼叫的特征结构，以及呼叫者的顺序、呼叫者的社会地位以及发起出发的个体。“出发”隆隆声之前在紧密的家庭群体中被描述为在协调出发时保持家庭团聚。雄性大象被描述为生活在松散的社会群体中，这一发现尤其引人注目。我们发现，这种声音协调发生在紧密相关、高度结合的个体群体中，很少发生在松散的同伴之间。最有可能发起“出发”隆隆声的三个个体都是高度社会融合的，其中一个个体也是总体上最占优势的。这一发现表明，更具社会融合性的个体在离开水坑的情况下更有可能发起或带领一群紧密的同伴，就像高等级的雌性在家庭群体中那样。许多个体参与了叫声，而且出发期可能比出发前更短、更长或相同，这一切都表明，即使是由一个领头个体触发的，离开的行为也得到了一致认可。
