Reproductive inequality, or reproductive skew, drives natural selection, but has been difficult
to assess, particularly for males in species with promiscuous mating and slow life histories …

Humans exhibit major age-related shifts in social relationships along with changes in social
and emotional psychological processes that underpin these behavioural shifts. Does social …

In most male mammals, fitness is strongly shaped by competitive access to mates, a non-
shareable resource. How, then, did selection favor the evolution of cooperative social …

In animal societies, control over resources and reproduction is often biased towards one
sex. Yet, the ecological and evolutionary underpinnings of male–female power asymmetries …

Highlights•Some species form social bonds that facilitate cooperation and provide
benefits.•Adult male chimpanzees form some of the strongest and most stable social …

Researchers investigating the evolution of human aggression look to our closest living
relatives, bonobos (Pan paniscus) and chimpanzees (Pan troglodytes), as valuable sources …

Socioecological environments that promote frequent interaction and social tolerance have
favored the evolution of strong and equitable social bonds, which facilitate cooperation and …

Grooming interactions benefit groomers, but may have negative consequences for
bystanders. Grooming limits bystanders' grooming access and ensuing alliances could …

Chimpanzees (Pan troglodytes) have a complex mating system in which both sexes use
multiple tactics. Most copulations occur in group contexts, and high‐ranking males can gain …

Across vertebrates, species with intense male mating competition and high levels of sexual
dimorphism in body size generally exhibit dimorphism in age-specific fertility. Compared …