Lemurs groom-at-a-distance through vocal networks

"Vocal exchanges have been predicted to serve a social bonding function by allowing conspecifics to ‘groom-at-a-distance’. If vocalizations play a bonding role, then they should be mainly exchanged between the bonded conspecifics, and thus display high social selectivity that characterizes other affiliative behaviors such as grooming. However, whether or not vocal exchanges are driven by social bonds remains unclear. We studied the relationships between contact-calling networks and grooming networks in ring-tailed lemurs ( Lemur catta). Network analyses revealed that lemurs produce vocal responses to the calls of the group members whom they frequently groom. This vocal selectivity was robust enough to be replicated through a playback experiment. The relationships between grooming and contact-calling in lemurs, a species where grooming frequency reflects bond strength, demonstrates that vocal exchanges indicate the strong social bonds between conspecifics and may allow them to groom-at-a-distance."