with more stable social networks formed grooming networks that were significantly more complex, while groups with low stability networks formed far fewer grooming pairs. Interchange of favours Grooming is often offered by an individual in exchange for a certain behavioural response or action. Social grooming is critical for vampire bats especially, since it is necessary for them to maintain food-sharing relationships in order to sustain their food regurgitation sharing behaviour. In Tibetan macaques, infants are seen as a valuable commodity that can be exchanged for favours; mothers allow non-mothers to handle their infants for short durations in exchange for being groomed. Tibetan macaques measure and perceive the value of the infants by noting the relative ratio of infants in the group; as the number of infants increase, their 'value' decreases and the amount of grooming in exchange for infant-handling performed by non-mothers for mothers decreases. In male bonobos, it is suggested that grooming is exchanged in favour of some emotional component because grooming familiar individuals involves larger time differences (i.e. the duration for which each individual grooms the other is not equal) and reduced reciprocity (i.e. likelihood of grooming the other is unpredictable). Hence, the presence of some sort of social bond between individuals results in greater 'generosity' and tolerance between them. Direct fitness consequences Social grooming relationships have been proven to provide direct fitness benefits to a variety of species. In particular, grooming in yellow baboons (Papio cynocephalus) has been studied extensively, with numerous studies showing an increase in fitness as a result of social bonds formed through social grooming behavior. One such study, which collected 16 years of behavioral data on wild baboons, highlights the effects that sociality has on infant survival. A positive relationship is established between infant survival to one year and a composite sociality index, a measure of sociality based on proximity and social grooming. Evidence has also been provided for the effect of sociality on adult survival in wild baboons. Direct correlations between measures of social connectedness (which focuses on social grooming) and median survival time for both female and male baboons were modeled. Social bonds established by grooming may provide an adaptive advantage in the form of conflict resolution and protection from aggression. In wild savannah baboons, social affiliations are shown to augment fitness by increasing tolerance from more dominant group members and increasing the chance of obtaining aid from conspecifics during instances