Adult meerkats modify close call rate in the presence of pups

Abstract

In animals, signaling behavior is often context-dependent, with variation in the probability of emitting certain signals dependent on fitness advantages. Senders may adjust signaling rate depending on receiver identity, presence of audiences, or noise masking the signal, all of which can affect the benefits and costs of signal production. In the cooperative breeding meerkat Suricata suricatta, group members emit soft contact calls, termed as “close calls”, while foraging in order to maintain group cohesion. Here, we investigated how the close calling rate during foraging was affected by the presence of pups, that produce continuous, noisy begging calls as they follow older group members. Adults decreased their overall close call rate substantially when pups were foraging with the group in comparison to periods when no pups were present. We suggest this decrease was likely due to a masking effect of the loud begging calls, which makes the close call function of maintaining group cohesion partly redundant as the centrally located begging calls can be used instead to maintain cohesion. There was some support that adults use close calls strategically to attract specific pups based on fitness advantages, that is, as the philopatric sex, females should call more than males and more to female pups than male pups. Dominant females called more than dominant males when a pup was in close proximity, while subordinates showed no sex-based differences. The sex of the nearest pup did not affect the calling rate of adults. The study shows that meerkats modify their close call production depending on benefits gained from calling and provides an example of the flexible use of one calling system in the presence of another, here contact calls versus begging calls, within the same species.

Bioacoustic monitoring of animal vocal behavior for conservation

“…During learning, the calls of young individuals can be highly variable. In the meerkat, Suricata suricatta, the call rate of the adults' close contact calls decreases when pups are foraging with the group, presumably a response to the loud and continuous begging calls given by the pups (Wyman, Rivers, Muller, Toni, & Manser, 2017). Infants' food-associated repertoire decreases over time as they learn which vocalizations are relevant to feeding.…”

“…The presence of juveniles in a group may also be indicated by changes in the composition or rate of a group's calls. In the meerkat, Suricata suricatta, the call rate of the adults' close contact calls decreases when pups are foraging with the group, presumably a response to the loud and continuous begging calls given by the pups (Wyman, Rivers, Muller, Toni, & Manser, 2017). Additionally, since frequency is strongly affected by the size of the individual's vocal anatomy, the presence of young individuals in a group may be detectable by the greater acoustic energy at higher frequencies.…”

Signalling adjustments to direct and indirect environmental effects on signal perception in meerkats

“…For example, during wet summer periods vegetation in dry savanna habitats is a lot denser and higher than during dry summer periods [24][25][26][27][28]. Background noise, such as wind [10,11] or the presence of noisy sympatric living species [29][30][31] and/or conspecifics [32], are further factors that can influence signal perception directly. Indirect effects on signal perception will mostly relate to the spacing among conspecifics.…”

“…While foraging, close calls, low amplitude contact calls, are the most frequently emitted vocalization, functioning to maintain group cohesion [21,37]. When pups are present, meerkats reduce their close call rate, presumably to avoid attracting the attention of begging pups or to avoid information redundancy, and might thus use the much louder pup vocalizations to localize the centre of the foraging group [32].…”

Introduction to the special column: communication, cooperation, and cognition in predators

“…Finally, Wyman et al (2017) examine the role of social effects in modifying the communicative behavior of cooperative group-living meerkats. Information reliability, and the role of dominance and signaler identity (shown on the lower axis of Figure 1 ) play a major role in shaping the acoustic structure of a group’s communication signals.…”