Calves as social hubs: dynamics of the social network within sperm whale units
Calves as social hubs: dynamics of the social network within sperm whale units
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DOI：
10.1098/rspb.2013.1113
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发表时间：
2013-07-22
影响因子：
4.7
通讯作者：
Whitehead, Hal
中科院分区：
文献类型：
--
作者：
Gero, Shane;Gordon, Jonathan;Whitehead, Hal
据推测，雌性抹香鲸（Physeter macrocephalus）之间永久社会关系的主要功能是在母亲潜水觅食时为海面上的幼鲸提供其他食物。为了研究抹香鲸单位内部分配的互惠性如何促进群体生活，我们基于年度关联矩阵（2005-2010）构建了加权社会网络，并通过年龄和社会角色的变化将它们跨年关联起来，研究了7个抹香鲸单位内部社会关系的变化。连续年份的关联矩阵对显示出比随机预期更大的正相关，但随着时间滞后的增加，相关系数减小。在所有考虑的单位中，小牛在所有测量的网络统计数据中都有很高的值，而母亲在大多数测量中都有中间值，但在连通性和亲和力方面有很高的值。母亲们在新生幼崽出生的第一年表现出力量和联系的急剧下降。这些广泛的模式似乎在各个单位都是一致的。幼崽似乎是社会单位网络中的重要节点，因此为集体关怀是该物种群体形成背后的进化力量这一理论提供了定量支持。
It is hypothesized that the primary function of permanent social relationships among female sperm whales (Physeter macrocephalus) is to provide allomothers for calves at the surface while mothers make foraging dives. In order to investigate how reciprocity of allocare within units of sperm whales facilitates group living, we constructed weighted social networks based on yearly matrices of associations (2005-2010) and correlated them across years, through changes in age and social role, to study changes in social relationships within seven sperm whale units. Pairs of association matrices from sequential years showed a greater positive correlation than expected by chance, but as the time lag increased, the correlation coefficients decreased. Over all units considered, calves had high values for all measured network statistics, while mothers had intermediate values for most of the measures, but high values for connectedness and affinity. Mothers showed sharp drops in strength and connectedness in the first year of their new calves' lives. These broad patterns appear to be consistent across units. Calves appeared to be significant nodes in the network of the social unit, and thus provide quantitative support for the theory in which communal care acts as the evolutionary force behind group formation in this species.