Studies of the social behavior of Cuvier's beaked whales (Ziphius cavirostris) are challenging because of their deep-water habitat usually far from shore and the limited time they spend at the surface. The sociality of these deepest diving mammals is of interest, however, especially for our understanding of how social systems evolve in extreme habitats. High levels of scarring suggest that males compete agonistically for access to females and so we predicted that associations among adult males would be unstable due to competitive exclusion. We tested this prediction by evaluating the diving behavior of animals within social groups off Cape Hatteras, North Carolina, considering diving synchrony a proxy for group membership. Using data from satellite-linked depth-recording tags, we found that adult male–male pairs showed extended periods of synchrony in diving behavior, while all pairs that included an adult male with an individual of another age and/or sex dove synchronously for less than a day. We assessed three hypotheses to explain these surprising results: sexual segregation; extended bouts of male–male competition; and the presence of male alliances. Finally, we considered testable predictions to distinguish among these explanations.

中文翻译：

---

成年雄性居维叶喙鲸（Ziphius cavirostris）进行长时间的同步潜水

居维叶喙鲸（Ziphius cavirostris ）的社会行为研究) 具有挑战性，因为它们的深水栖息地通常远离海岸，而且它们在水面停留的时间有限。然而，这些潜水最深的哺乳动物的社会性令人感兴趣，特别是对于我们了解社会系统如何在极端栖息地中进化。高水平的疤痕表明雄性为了接近雌性而激烈竞争，因此我们预测成年雄性之间的关联会由于竞争排斥而不稳定。我们通过评估北卡罗来纳州哈特拉斯角附近社会群体中动物的潜水行为来测试这一预测，将潜水同步性视为群体成员资格的代表。使用来自卫星链接的深度记录标签的数据，我们发现成年男性 - 男性对在潜水行为上表现出长时间的同步，而包括成年男性和其他年龄和/或性别的个体在内的所有配对都同步潜水不到一天。我们评估了三个假设来解释这些令人惊讶的结果：性别隔离；男女比赛的延长赛；以及男性联盟的存在。最后，我们考虑了可测试的预测来区分这些解释。