A team from the University of Geneva, the National Center of Competence in Research (NCCR) Evolving Language, the reConnect Institute, andInstitut Pasteur that nearly all animal species have been vocalizing in a common rhythm for hundreds of millions of years.
From insects to great apes, including birds and fish, animals communicate using all kinds of sounds. While the pitch or timbre of their vocalizations is important, rhythm appears to play a fundamental role. Scientists from the University of Geneva (UNIGE), the NCCR Evolving Language, the reConnect Institute, andInstitut Pasteur more than 2,000 sound recordings from 98 animal species. All vocalize at a surprisingly similar rate—about two to three acoustic events per second—regardless of their size, environment, species, or social complexity. This constraint is likely linked to the brain’s ability to process auditory stimuli, and human language is no exception. These findings are published in PLOS Biology.
To communicate, many animal species use acoustic signals—calls, songs, or vocalizations—that vary in frequency and pitch. “But what about rhythm? Is there a common tempo, or does it adapt to the characteristics of each species? It is this temporal dimension that we wanted to examine,” says Anne-Lise Giraud, director of the reConnect Institute, a researcher atInstitut Pasteur a full professor in the Department of Basic Neuroscience at the UNIGE Faculty of Medicine, who led this research.
Scientists analyzed the sounds produced by 98 species—mammals, birds, amphibians, insects, reptiles, and fish—by developing a method to calculate the rhythm of vocalizations in a standardized way, and then assessing which factors might influence it. “We observed that 95% of them fall between 0.45 and 4.99 vocalizations per second, with a marked concentration around 2.8 Hz—a surprising consistency for animals that are otherwise so different,” notes Théophane Piette, a postdoctoral researcher in the Department of Basic Neuroscience at the UNIGE Faculty of Medicine and the study’s first author. “Neither body weight, nor lung capacity, nor the complexity of social relationships, nor the living environment proved to be decisive factors. This suggests that this rhythm is shaped by a common, ancient constraint shared across species rather than by recent adaptations.”
A neurological explanation
To analyze a sound, the brain must integrate both its overall structure and its details. Scientists therefore hypothesize that auditory systems have evolved around two complementary temporal scales. Slow oscillations, particularly in the delta band (1 to 4 Hz), are thought to provide a long integration window that allows for tracking acoustic sequences and identifying the general structure of sounds. This rhythm also corresponds to that observed in many animal vocalizations. Conversely, faster processes, likely in the low-gamma bands, would allow for fine-grained temporal discrimination of sounds and the analysis of their detailed acoustic structure. These rapid mechanisms would contribute, in particular, to the identification of speakers or sound sources.
Toward cross-species communication?
Humans are no exception to this universal rule in the animal kingdom. Although our speaking rate is slightly higher than the average for animals—partly due to the way language is structured into syllables, words, and sentences—we naturally slow down in situations where communication is difficult: background noise, an elderly conversation partner, or a young child. This shared rhythm could have another consequence: facilitating communication between species. If most animals emit and receive signals at the same rate, they might be able to decode signals produced by other species. This is exactly what dogs do with their owners: they process human speech at this same slow rate, and humans, in turn, tend to slow down their speech when addressing them. “This shared rhythm may not only reflect how brains process sounds; it could also constitute a kind of universal synchronization that facilitates communication between species,” concludes Théophane Piette. This study is part of the work of the NCCR Evolving Language, co-led by the Universities of Geneva, Zurich, and Neuchâtel, which aims to understand the biological foundations of language, its evolutionary origins, and the challenges posed by new technologies.
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About the reConnect Institute, a foundation under the auspices ofInstitut Pasteur
<br>Créé en avril 2024, l'Institut reConnect fédère les acteurs clés de la santé auditive et des troubles cognitifs et de la parole pour améliorer leur détection et leur prise en charge. Pôle d'excellence dans ce domaine, il vise à compléter une médecine compensatrice d'une médecine réparatrice au cours de la prochaine décennie grâce aux découvertes scientifiques réalisées au cours des vingt dernières années dans le domaine de la génétique et des neurosciences. L'Institut reConnect est une fondation sous l'égide de l'Institut Pasteur, portée par l'Institut de l'Audition, centre de l'Institut Pasteur avec la Fondation Pour l'Audition, l'AP-HP, l'université Paris Cité et l'Inserm, membres fondateurs de l'Institut.
About theInstitut Pasteur
A foundation recognized as being of public utility, established by decree in 1887 at the initiative of Louis Pasteur,Institut Pasteur today an internationally renowned biomedical research center. To fulfill its mission of combating disease in France and around the world,Institut Pasteur its activities in four areas: research, public health, education, and the development of research applications. A recognized global leader in the fields of infectious diseases, microbiology, and immunology,Institut Pasteur dedicated to the study of living organisms . Its research thus focuses on emerging infectious diseases, antimicrobial resistance, certain cancers, neurodegenerative diseases, and disorders of brain connectivity. To enhance the excellence of its research,Institut Pasteur and develops a state-of-the-art technological environment, including in fields such as nanoimaging, computational biology, and artificial intelligence. Since its founding, 10 researchers working atInstitut Pasteur been awarded the Nobel Prize in Medicine, most recently in 2008 in recognition of their 1983 discovery of the human immunodeficiency virus (HIV), which causes AIDS.Institut Pasteur a member of the Pasteur Network, a global network of more than 30 members across five continents, united by shared Pasteurian values, which contribute to the improvement of human health. Since July 1, 2021,Institut Pasteur a research partner of Université Paris Cité. https://www.pasteur.fr/fr/presse
