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

The occurrence of cooperation poses a problem for the biological and social sciences.
However, many aspects of the biological and social science literatures on this subject have …

Somewhere in Africa, more than a million years ago, a line of apes began to rear their young
differently than their Great Ape ancestors. From this new form of care came new ways of …

Darwin developed the theory of sexual selection to account for the evolution of weaponry,
ornamentation and other secondary sexual characters that are commonly more developed …

Social interactions are essential for animals to reproduce, defend their territory, and raise
their young. The conserved nature of social behaviors across animal species suggests that …

Although competition between females is one of the cornerstones of the theory of natural
selection, most studies of reproductive competition have focussed principally on mating …

Models of population dynamics generally neglect the presence of males. While this
assumption holds under many circumstances, behavioural ecology increasingly tells us that …

In cooperatively breeding species, subordinates typically suffer strong constraints on within-
group reproduction. While numerous studies have highlighted the additional fitness benefits …

Traditional interpretations of the evolution of animal societies have suggested that their
structure is a consequence of attempts by individuals to maximize their inclusive fitness …

In most mammalian species, females regularly interact with kin, which is expected to reduce
aggressive competitive behaviour among females. It may thus be difficult to understand why …