In The Hadza, Frank Marlowe provides a quantitative ethnography of one of the last
remaining societies of hunter-gatherers in the world. The Hadza, who inhabit an area of East …

Attempts to account for observed variation in the degree of reproductive skew among
cooperative breeders have usually assumed that subordinate breeding has fitness costs to …

Reproductive skew has been identified as a major dimension along which animal societies
vary. Two major kinds of reproductive skew models are transactional models, which explain …

The number of adult males in a group is one of the most variable aspects ofprimate social
organization. The causes for this variation have constituted alongstanding focus in …

When animals live in groups, individuals can invest in resources themselves or exploit the
investments of other group members. Grouping with kin may reduce the frequency of …

Offspring often compete over limited available resources. Such sibling competition may be
detrimental to parents both because it entails wasted expenditure and because it allows …

While competition for limited breeding positions is a common feature of group life, species
vary widely in the extent to which reproduction is shared among females ('reproductive …

In biological systems, as in human society, competing social groups may depend heavily on
a small number of volunteers to advance the group's prospects. This phenomenon can be …

In many social sciurids, male territoriality confers significant mating advantages. We
evaluated resident male paternity in Gunnison's prairie dogs (Cynomys gunnisoni), a …