Thesis defense : Léo Papet

Crocodilians, as other Archosaurs (including birds and dinosaurs), use acoustic communication. To communicate using sounds, they have to analyse the acoustic environment and to localise all sound sources. Previous electrophysiological studies have suggested that crocodilians could benefit from interaural acoustic differences to localise sounds. However, this result has not been confirmed yet by behavioural studies. Here, several studies have been conducted to explore sound localisation abilities in crocodilians: to identify which acoustic cues are useful to localise a sound in space, to quantify their sound localisation abilities and to describe how they can benefit from the sources spatial separation to detect a sound embedded in noise. The first study determined the acoustic cues that could enable to encode the position of a sound source, even when only a small part of the head is emerged. Moreover, the following studies showed that trained crocodiles localise sounds with a great precision and can use both Interaural Time Differences (ITD) and Interaural Level Differences (ILD). Finally, in the presence of noise in their environment, crocodilians perform spatial release from masking to increase the detection of a relevant acoustic signals. Altogether, theses studies showed high sound localisation abilities in crocodilians.

Jury Composition :

- Thierry Aubin, Directeur de recherche au CNRS, Université Paris-Sacaly
- Colleen Reichmuth, Directrice de recherche, Université de Californie Santa Cruz
- Élodie Mandel-Brieffer, Maîtresse de conférence, Université de Copenhague
- Sabine Meunier, Chargée de recherche au CNRS, LMA Marseille
- Karyn Julliard, Professeure des universités, Université Lyon 1
- Nicolas Grimault, Chargé de recherche au CNRS, CRNL Lyon
- Nicolas Mathevon, Professeur des universités, Université Jean Monnet de Saint-Étienne