Similar but different: dynamic social network analysis highlights fundamental differences between the fission-fusion societies of two equid species, the onager and Grevy's zebra

Understanding why animal societies take on the form that they do has benefited from insights gained by applying social network analysis to patterns of individual associations. Such analyses typically aggregate data over long time periods even though most selective forces that shape sociality have strong temporal elements. By explicitly incorporating the temporal signal in social interaction data we re-examine the network dynamics of the social systems of the evolutionarily closely-related Grevy’s zebras and wild asses that show broadly similar social organizations. By identifying dynamic communities, previously hidden differences emerge: Grevy’s zebras show more modularity than wild asses and in wild asses most communities consist of solitary individuals; and in Grevy’s zebras, lactating females show a greater propensity to switch communities than non-lactating females and males. Both patterns were missed by static network analyses and in general, adding a temporal dimension provides in...

探究动物社会何以形成当前形态的研究，常借助将社交网络分析（social network analysis）应用于个体关联模式的方法，获得诸多关键洞见。尽管塑造社会性的多数选择压力均具有显著的时间维度特征，但此类分析通常会将数据在长时段内进行聚合。通过将时间信号明确纳入社交互动数据中，我们重新审视了进化上亲缘关系密切、社会组织大体相似的细纹斑马（Grevy’s zebra）与野驴（wild ass）的社交系统网络动态。通过识别动态社群，此前被掩盖的差异得以显现：细纹斑马的网络模块性高于野驴，且野驴的多数社群由独居个体构成；而在细纹斑马中，泌乳雌性相较于非泌乳雌性与雄性，展现出更高的社群切换倾向。静态网络分析未能捕捉到这两种模式，总体而言，纳入时间维度可为