Data from: Isochrony in Titi Monkeys duets: Social context as a proximate cause of duets’ rhythm and regularity

Music and rhythm are typical features of all human cultures, but their
biological origins remain unclear. Recent investigations suggest that
rhythmic features of human music are shared with animal vocalizations.
Moreover, emotions influence human speech and music, similar to what
arousal does to the structure of animal sounds. We investigated Coppery
titi monkeys' (Plecturocebus cupreus) duet rhythms to assess
adherence to rhythmic patterns previously observed only in Old World
primates and to deepen our understanding of the proximate causes of
non-human primate song rhythm. Titis’ songs were remarkably isochronous,
but their tempo depended on the social context: songs sung during
territorial confrontations have a slower pace than during early morning
singing. Songs had a faster tempo and were less regular when infants were
present, suggesting a speed-accuracy tradeoff. Finally, we found that
pair-mates perform isochronous songs with the same precision, suggesting
that isochrony plays a role in boosting pair coordination, as it does in
other singing primates. Our investigation shed light on the ultimate and
proximate causes of primates' isochronous rhythm, confirming its
presence for the first time in a New World monkey and highlighting the
role of social factors in shaping its timing and regularity in the short
term.