Social complexity has been one of the recent emerging topics in the study of animal and
human societies, but the concept remains both poorly defined and understood. In this paper …

BACKGROUND Whereas early studies of animal evolution focused principally on the
adaptations of different species to their physical environment, more recent studies have …

The evolution of social monogamy has intrigued biologists for over a century. Here, we show
that the ancestral condition for all mammalian groups is of solitary individuals and that social …

The study of language evolution, and human cognitive evolution more generally, has often
been ridiculed as unscientific, but in fact it differs little from many other disciplines that …

Since Hamilton published his seminal papers in 1964, our understanding of the importance
of cooperation for life on Earth has evolved beyond recognition. Early research was focused …

Despite a long history of study, consensus on a human-typical mating system remains
elusive. While a simple classification would be useful for cross-species comparisons, across …

Discerning the relationship between sociality and longevity would permit a deeper
understanding of how animal life history evolved. Here, we perform a phylogenetic …

Darwin famously described special difficulties in explaining social evolution in insects. More
than a century later, the evolution of sociality-defined broadly as cooperative group living …

Hamilton's rule is a central theorem of inclusive fitness (kin selection) theory and predicts
that social behaviour evolves under specific combinations of relatedness, benefit and cost …

Behavior is a way for organisms to respond flexibly to the environmental conditions they
encounter. Our own species exhibits large behavioral flexibility and occurs in all terrestrial …