Cross-population variation in usage of a call combination: evidence of signal usage flexibility in wild bonobos.

The arbitrary relationship between signifier and signified is one of the features responsible for language's extreme lability, adaptability, and expressiveness. Understanding this arbitrariness and its emergence is essential in any account of the evolution of language. To shed light on the phylogeny of the phenomenon, comparative data examining the relationship between signal form and function in the communication systems of non-humans is central.

The acoustic structure of spider monkey (Ateles geoffroyi) calls is related both to caller goal and arousal.

Analyzing the factors related to the acoustic structure of primate calls is fundamental to identifying the potential information these signals convey, and therefore, their potential function. It is well-accepted that caller arousal is an important driver of acoustic variation in call structure. However, evidence suggests that arousal alone cannot explain the production of calls with different acoustic structures.

Dominance style is a key predictor of vocal use and evolution across nonhuman primates.

Animal communication has long been thought to be subject to pressures and constraints associated with social relationships. However, our understanding of how the nature and quality of social relationships relates to the use and evolution of communication is limited by a lack of directly comparable methods across multiple levels of analysis. Here, we analysed observational data from 111 wild groups belonging to 26 non-human primate species, to test how vocal communication relates to dominance style (the strictness with which a dominance hierarchy is enforced, ranging from 'despotic' to 'tolerant').

Call type signals caller goal: a new take on ultimate and proximate influences in vocal production.

After 40 years of debate it remains unclear whether signallers produce vocalizations in order to provide receivers with information about call context or external stimuli. This has led some researchers to propose that call production is arousal- or affect-based. Although arousal influences certain acoustic parameters within a call type, we argue that it cannot explain why individuals across vertebrates produce different call types.