Volubility and vocal coordination under information asymmetry in captive common marmosets (Callithrix jacchus)

Abstract

Volubility - the number of vocalizations per unit of time - is an understudied aspect of animal communication, potentially crucial in cooperatively breeding species that depend on coordinated behavior. Callitrichid monkeys such as common marmosets (Callithrix jacchus) are often characterized as highly vocal, yet variation in their calling rates remains poorly quantified. We recorded 69,538 vocalizations from 45 captive marmosets tested in dyads across six experimental conditions. Total call rates varied with condition but not with caller sex or status. Alertness call production depended on caller status: breeders showed context-appropriate responses to an ambiguous object, whereas helpers responded more generally. Food calls were tightly coupled to feeding rather than food availability, with males calling more than females. Dyadic analyses revealed call-type-specific covariation between subjects and partners, consistent with vocal contagion for alertness calls and recruitment for food calls. These patterns indicate flexible, call-type-specific volubility and information sharing beyond simple arousal contagion.