Formally, African colobines were not thought to be affected by food competition because mature leaves are relatively evenly distributed and low quality. However, greater research on colobus monkeys has shown that they have varied diets and rarely rely on mature leaves and that within-group scramble and both within- and between-group contest competition for food affects them. Within-group contest competition for resources may be seasonal but appears to be sufficient to lead to dominance hierarchies among females. These dominance hierarchies tend to be individualistic and females typically do not stay with kin to defend food. Unfortunately, there are still little data available to examine whether female dominance hierarchies lead to rank-effects on female energy intake or reproductive rates. In sum, African colobines do not seem fit current socio-ecological models and instead appear to fall somewhere between species with within-group scramble and within-group contest competition, where females disperse despite forming decided dominance relations. This appears to give rise to very specific male strategies, such as male defence of food resources, that may attract females and which alter female social strategies in interesting ways, changing social organization and structure.