Girneys

Vocalizations modified by a process of lip movement on teeth scraping is characteristic of atonal girneys. An adult female will produce this distinct call when approaching a cluster of females and infants late in the birth season, particularly when orientated toward the infant of the group.[2]

Tonal girneys are more morphologically variable than atonal girneys as the characteristic tongue and lip movements are superimposed. The call is produced by an adult female who intends to participate in grooming with an unrelated dominant female. The subordinate directs the call while the dominant is separate from the cluster during birth season.[2]

Girneys are used in a variety of contexts but consistently function to ease affiliative social interactions between unrelated members of the same species and are generally directed from the subordinate monkey to the dominant monkey.

Male macaque do not often participate in infant care, so mothers tend to be highly protective of their infants and will display highly aggressive behavior and even physically attack monkeys who come within close proximity. In attempt to establish friendly contact with mother and minimize chance of attack, the subordinate adult female will produce girneys.[2] The call can also benefit the adult female in that it may increase probability of affiliative physical contact such as grooming, which reduces stress. Monkeys who do not produce the call upon approaching mother-offspring dyad are less likely to attain access to an affiliative interaction. Additionally, females without infants may be allowed access to handling an unrelated mothers infant after initiating friendly contact with girneys. In this case, they often continue to make the call during handling.[1]

Japanese macaques form despotic societies in which some members of group are ranked higher than others. The higher ranking macaques are considered dominant, and macaques of lower rank will produce girneys when in close proximity to dominant members, to signal appeasement and acknowledge inferiority. Low ranking females without infants are the least likely to receive girneys while high ranking females with infants are most likely to receive girneys within a troop. This is coherent with the proposition that girneys function to reduce tension, as low ranking females without infants are more likely to be victims of aggression than any other member of troop.[2]

Opponents of a conflict are attracted to each other for a short period of time following the conflict. During this time, the victim will produce girneys in attempt to restore friendly relations with former opponent. The victim is more likely to use the vocalization when opponent is less familiar, indicating that the production of girneys after conflict is dependent on how predictable the winner is to the victim. Despite the reconciliation intent of girneys, victims make themselves vulnerable to further aggression when initiating post conflict affiliation. So it is unclear if the vocalizations are effective in this context.[3]