Alarm call modification by prairie dogs in the presence of juveniles

Abstract

While several drivers of wildlife alarm calls have been identified, recent work on the impact of the audience in the plasticity of alarm calling indicates that intraspecific communication can drive the behavior. We build on this literature by assessing changes in call characteristics in black-tailed prairie dogs (Cynomys ludovicianus) in the presence of recently emerged juveniles. Alarm calls were elicited by approaching individuals, and then recorded using a shotgun microphone. Presence and distance of pups were noted prior to recording. Alarm calls were analyzed for changes in spectral and temporal characteristics relative to those of adults who were not in the immediate presence of pups. Our analyses indicated that adult prairie dogs lowered the central concentration of energy in their alarm calls when calling in the presence of pups. This may show that prairie dogs are conscious of the type of alarm call produced based on the behavioral context of the calling and potentially the audience receiving the message. Furthermore, this may support that alarm calling is intended to reach conspecifics, rather than to send a message to the predator itself.

Biological Functions of Rat Ultrasonic Vocalizations, Arousal Mechanisms, and Call Initiation

“…This is a valid comparison because human non-verbal vocalizations, such as crying, laughing, grunting, groaning, moaning, or shrieking, do not have lexical content, are generated by subcortical limbic mechanisms, and are evolutionary counterparts of other mammalian vocalizations (for classification of human verbal and non-verbal vocalizations as well as pathological vocalizations, see [ 10 ]). Although animal vocalizations have many subtypes and may convey referential information or be situation-specific (e.g., in species of prairie dogs [ 11 , 12 , 13 ]), they do not represent language in a human sense and do not have grammatical structure, sentences, words, syllables, or even fully translatable meaning. Naming mammalian vocalizations as syllables, particularly those emitted in series, is a misnomer and mistake that is still repeated in the literature.…”

Vocal characteristics of prairie dog alarm calls across an urban noise gradient

“…This is especially pertinent given that the function of the alarm call is to both warn conspecifics of approaching danger and to communicate to the predator that they have been detected (Isbell and Bidner 2016). Additional experiments conducted by our research group demonstrated that prairie dogs adjusted their alarm calls -reducing the central concentration of energy -when calling in the presence of vulnerable pups (Wilson-Henjum et al 2019). Adjustment in prairie dog communication, therefore, appears to be structured by social context mediated by spatial proximity to an approaching threat.…”

“…This provides evidence that the seemingly costly behaviour of an individual alerting a predator to their presence may have indirect fitness benefits (Shelley and Blumstein 2005). Moreover, we recently demonstrated that the presence of young influenced the alarm call characteristics of adult prairie dogswhereby they lowered the central concentration of energy in their calls (Wilson-Henjum et al 2019). The social context and function of alarm call production provides an interesting avenue for exploring the effects of exposure to anthropogenic noise on animal vocalisation, particularly when contrasted with findings from the significant body of work focussing on advertisement calls and songs (reviewed by Shannon, McKenna, et al 2016).…”

Vibrational and Acoustic Communication in Animals

“…The development of this messaging system becomes intricate with human language. Whether the degree of development of the young at birth (which could relate to cognitive development; Scheiber et al 2017;Wilson-Henjum et al 2019) influences the complexity of vocalizations and other displays are yet to be determined.…”