Data from: The importance of delineating networks by activity type in bottlenose dolphins (Tursiops truncatus) in Cedar Key, Florida

Network analysis has proved to be a valuable tool for studying the behavioural patterns of complex social animals. Often such studies either do not distinguish between different behavioural states of the organisms, or simply focus attention on a single behavioural state to the exclusion of all others. In either of these approaches it is impossible to ascertain how the behavioural patterns of individuals depends on the type of activity they are engaged in. Here we report on a network-based analysis of the behavioural associations in a population of bottlenose dolphins (Tursiops truncatus) in Cedar Key, Florida. We consider three distinct behavioural states — socialising, travelling, and foraging — and analyse the association networks corresponding to each activity. Moreover, in constructing the different activity networks we do not simply record a spatial association between two individuals as being either present or absent, but rather quantify the degree of any association, thus allowing us to construct weighted networks describing each activity. The results of these weighted activity networks indicate that networks can reveal detailed patterns of bottlenose dolphins at the population level: dolphins socialise in large groups with preferential associations; travel in small groups with preferential associates and spread out to forage in very small, weakly connected groups. There is some overlap in the Socialise and Travel networks but little overlap between the Forage and other networks. This indicates that the social bonds maintained in other activities are less important as they forage on dispersed, solitary prey. The Overall network, not sorted by activity, does not accurately represent any of these patterns.网络分析已被证明是研究复杂社会性动物行为模式的有力工具。此类研究往往要么未区分研究对象的不同行为状态，要么仅聚焦于单一行为状态而完全忽略其余状态。采用这两种研究范式，均无法确定个体的行为模式如何随其所参与的活动类型发生变化。本研究针对佛罗里达州锡达基海域的宽吻海豚（Tursiops truncatus）种群开展行为关联的网络分析，现将结果报道如下。我们选取三种明确的行为状态：社交、移动与觅食，并针对每种活动对应的关联网络展开分析。此外，在构建不同活动网络时，我们并未简单将两个体间的空间关联记录为存在或不存在两种二元状态，而是对关联强度进行量化，由此得以构建描述每种活动的加权网络。这些加权活动网络的分析结果表明，网络分析可揭示种群层面宽吻海豚的精细行为模式：海豚会以具有偏好性关联的个体组成大型群体进行社交；以存在偏好关联的小型群体移动，并分散为规模极小、连接松散的群体开展觅食活动。社交网络与移动网络存在一定重叠，但觅食网络与其余两类网络的重叠度极低。这表明当海豚以分散的独居猎物为觅食对象时，其他活动中维系的社会纽带对其觅食行为的影响相对较弱。未按活动类型分类的总网络，无法准确反映上述任何一种行为模式。