Abstract
Flexible vocal production has been demonstrated in several vertebrate species with much work focusing on the role of the social “audience” in explaining variation in call production. It is, however, likely that the decision to call is an emergent property of both external and internal factors and the extent to which these factors are integrated has been little investigated. We addressed this question by examining the production of alarm calls in wild male meerkats (Suricata suricatta) in different social environments and different predator-encounter contexts. Males searching for reproductive opportunities (rovers), were followed: (i) in their home group and when prospecting, either (ii) solitarily, or (iii) in a coalition with other males. Results showed conspecific presence influenced the production of flee-alarm and recruitment calls. Solitary rovers were less likely to produce flee-alarm calls compared to when with conspecifics, whether coalitionary rovers or the rover’s home group. Experimentally elicited recruitment calls were also produced less when males were solitary than when in their home group. Bark vocalisations, emitted when meerkats were safe were always produced, irrespective of conspecific presence, indicating these calls function to address predators. The probability of producing flee-alarms also increased with urgency of the predation event. Our results indicate that variation in alarm call production depends on whom the call is addressed to, and also the motivational state of the caller. We argue that neglecting to integrate internal and external factors when elucidating mechanisms underlying vocal production can potentially lead to misguided, parsimonious conclusions regarding vocal flexibility in animals.
Townsend, Simon