Social animals self-organise to create groups to increase protection against predators and productivity. One-to-one interactions are the building blocks of these emergent social structures and may correspond to friendship, grooming, communication, among other social relations. These structures should be robust to failures and provide efficient communication to compensate the costs of forming and maintaining the social contacts but the specific purpose of each social interaction regulates the evolution of the respective social networks. We collate 611 animal social networks and show that the number of social contacts $E$ scales with group size $N$ as a super-linear power-law $E=CN^{\beta}$ for various species of animals, including humans, other mammals and non-mammals. We identify that the power-law exponent $\beta$ varies according to the social function of the interactions as $\beta = 1+a/4$, with $a \approx {1,2,3,4}$. By fitting a multi-layer model to our data, we observe that the cost to cross social groups also varies according to social function. Relatively low costs are observed for physical contact, grooming and group membership which lead to small groups with high and constant social clustering. Offline friendship has similar patterns while online friendship shows weak social structures. The intermediate case of spatial proximity ($\beta=1.5$ and clustering dependency on network size quantitatively similar to friendship) suggests that proximity interactions may be as relevant for the spread of infectious diseases as for social processes like friendship.
翻译:我们整理了611个动物社交网络,并显示社会接触的规模为E美元,其规模与我们的数据相匹配的多层次模式,我们观察到跨社会群体的成本也因社会功能的不同而不同。 相对而言,对于包括人类、其他哺乳动物和非哺乳动物在内的各种动物物种而言,其成本相对较低。 我们发现,权力法前方的美元($beta)=1+a/4美元,其社会互动的社会功能因美元=1+a/4美元的社会功能而不同,但每种社会互动的具体目的则制约着各个社会网络的演变。我们整理了611个动物社交网络,并表明,与我们的数据相匹配的多层次模式,与我们的数据相似,我们发现跨社会群体的成本也因社会功能而不同。对于实物接触、其他哺乳动物和非哺乳动物等动物来说,成本相对较低。我们发现,权力法前方的美元($\beta)前方美元($=1+a/4美元)与社会互动的社会功能不同,而社交关系中层组织则显示,社交关系中层(Sylodal commal somalal creal city clodistrate)为社会组织。