Group size, grooming and social cohesion in primates

  title={Group size, grooming and social cohesion in primates},
  author={Julia Lehmann and Amanda H. Korstjens and Robin I. M. Dunbar},
  journal={Animal Behaviour},

Figures and Tables from this paper

Network Structure and Social Complexity in Primates

Data is used on primate grooming networks to show that three different social grades can be differentiated in terms of network structuring, which seems to arise from a glass ceiling imposed on group size by limits on the time available for social grooming.

Social complexity and the fractal structure of group size in primate social evolution

It is argued that the grades themselves represent glass ceilings on animals' capacity to maintain social and spatial coherence during foraging and that, in order to evolve more highly bonded groups, species have to be able to invest in costly forms of cognition.

Costs and benefits of group living in primates: group size effects on behaviour and demography

The effect of social and ecological factors on the time budget of wild vervet monkeys

The results indicate that intragroup competition may force larger groups to spend more time feeding and less time resting, and it is found that seasonal variation, and therefore food availability, has a strong influence on the monkeys’ activity budget.

Analysing the effects of group size and food competition on Japanese macaque social relationships

The results indicate that social relationships within the two groups were the result of the combination of group size differences and of the balance between the benefits and costs of a lower/greater level of inter- and intra-group food competition.

Human grooming in comparative perspective: People in six small-scale societies groom less but socialize just as much as expected for a typical primate.

It is found that human grooming may be a (recent) phylogenetic outlier when defined narrowly as parasite removal but not defined broadly as personal hygiene, and there was no support for thermoregulatory functions of grooming, and noSupport for the "vocal grooming" hypothesis of language having evolved as a less time-consuming means of bonding.



Neocortex size and social network size in primates

It is shown that, in respect of neocortex size, there are as many as four statistically distinct grades within the primates (including humans), and analysis of the patterns of grooming among males and females suggested that large primate social groups often consist of a set of smaller female subgroups that are linked by individual males.

Coevolution of neocortical size, group size and language in humans

It is suggested that the evolution of large groups in the human lineage depended on developing a more efficient method for time-sharing the processes of social bonding and that language uniquely fulfills this requirement.

Ecological constraints on group size: an analysis of spider monkey and chimpanzee subgroups

Field studies of spider monkeys and chimpanzees were used to test a model of ecological constraints on animal group size which suggests that group size is a function of travel costs and assess ecological and social factors underlying the social organization of these two species.

The effect of group size on time budgets and social behaviour in wild long-tailed macaques (Macaca fascicularis)

It is concluded that theories postulating feeding advantages to be the primary factor favouring group living do not apply in this case.

Determinants of Group Size in Primates : A General Model

A linear programming approach is used to develop a model of habitat-specific minimum and maximum group sizes for baboons, finding the maximum group size that animals’ neocortex size will allow them to maintain as a coherent stable social entity.

An Ecological Model of Female-Bonded Primate Groups

A model is presented to account for the evolution of FB groups in terms of ecological pressures on female relationships and suggests that relationships in most FB groups are ultimately related to feeding competition.

Cohort size and the allocation of social effort by female mountain baboons

Compared the grooming interactions of adult females from four troops in the Drakensberg mountains, it is argued that females attempt to groom all other females as well as sustain closer relationships with a few females through longer bouts of reciprocated grooming, likely to facilitate fission.

Ecological Determinants of Group Sizes of Foraging Lions

A number of authors have related ecological conditions to group size in birds and mammals to predict not only group sizes but sex ratios, sexual dimorphism, and mate-selection systems in response to resource distributions.

Market forces predict grooming reciprocity in female baboons

We argue that grooming is a commodity that female primates can trade, either for itself or in exchange for other services (sensu biological markets theory) and that the decision to do either will

Functional significance of social grooming in primates

Frequencies of social grooming recorded from 44 species of free-living primates correlate with group size but not body size. This is interpreted as evidence for the social function of grooming and