Duetting and Turn-Taking Patterns of Singing Mammals: From Genes to Vocal Plasticity, and Beyond

Mammalian vocal duets and turn-taking exchanges — long, coordinated acoustic signals exchanged between two individuals— are primarily found in family-living, pair-bonded mammals with a socially monogamous lifestyle (some rodents, some lemurs, tarsiers, titi monkeys, a Mentawai langur, gibbons and siamangs). Duetting and turn-taking patterns combine visual, chemical, tactile and auditory cues to produce some of the most exuberant displays in the realm of animal communication. How and why such phenotypes evolved independently across main lineages are fundamental questions at the core of the nature-nurture debate. Duetting styles ranging from antiphonal (non-overlapping) to simultaneous (overlapping) emissions have now been documented in various taxa, some of which are quite reminiscent of turn-taking rules in human conversation. Nonetheless, much remains to be learned about this complex motor skill, and at all four levels of analysis, namely (1) developmental processes, (2) causal mechanisms (3) functional properties and (4) evolutionary history. Given the strong link between this form of coordinated singing and pair-bonding, gaining a deeper understanding of this kind of cooperative behavior will likely shed more light on the deep evolutionary roots of human culture, language and music.

We propose creation of an interdisciplinary platform, aiming at fostering closer interaction between taxonomists, ecologists, ethologists, and molecular biologists. Towards this goal, we embrace both laboratory and field studies that relate mammalian vocal duets to the life-history strategies of the respective populations, including social structure, ecology, neuroscience, biogeography, taxonomy and genetics. While some researchers have taken up the challenge of resolving phenotypic and phylogenetic relationships using modern DNA sequencing methods, others are more specifically looking for clues of developmental plasticity and vocal flexibility in adulthood. Both these approaches are at the forefront of today’s research in singing mammals. A picture is gradually emerging in which duetting appears to have an instinctive (gene-driven) basis but also involves a learned (socially-driven) component.

Because the spectrographic analysis of vocal duets is particularly challenging in some primate lineages, we also welcome contributions making use of animal borne sensor applications for separating overlapping voices or those reporting new developments in computer-assisted research (via machine learning) for solving the cocktail party problem: how to decode targeted acoustic information from interfering sound sources. Finally, due to the rapid decline of nonhuman primates worldwide, a particular attention will be devoted to studies that use auditory sampling as a tool in population surveys – either via playback or passive acoustic monitoring of loud calls - towards conservation efforts.

This Research Topic is respectfully dedicated to the late Emeritus Professor Charles T. Snowdon; a distinguished scholar in the realms of Animal Behavior and Primatology.

This Research Topic has been developed in collaboration with Sofya Dolotovskaya (German Primate Center, Göttingen, Germany).