Guillaume Fosseries

Transition to aquatic life: undulatory kinematic of ophidian swimming

The return to the aquatic life shaped many organisms and had an impact on fossil and present marines’ ecosystems. However, study the evolutionary process involved is difficult; many key steps are missing in most present lineages. That’s not true for snakes. Every intermediaries exist and only one locomotion mode is efficient on ground and in water: the lateral undulation. The hypothesis of this project is that the adaptation to the aquatic life modified the kinematic of snakes’ undulation in order to optimize the swimming by reducing the drag forces and maximizing the propulsive forces. In this case, energetic effectiveness of the swimming would be better in aquatic species. Quantify this effectiveness and measure the athletic performances and kinematic at the same time is technically complicated. We decided here to measure the drag coefficient of the swimming for each individual. Therefore, knowledge in fluids mechanics and numerical modelling are necessary. This PhD is part of the DRAGON2 project, funded by the ANR, including collaborators specialized in these domains and in robotic. In fact, the conception of a snake robot is also an issue of the project.

To carry out this project, a directory of swimming kinematics with a variety of different species is necessary. My aim during this PhD is to record in laboratory and on field several swimming footages of many individuals and different species, which could be terrestrial, aquatic or marine, because almost all the snakes are capable to swim. The analysis of the videos will allow us to compare the athletic performances with the swimming kinematics recorded and then to understand how the adaptation to aquatic life influenced the undulatory locomotion, maybe by optimizing the frequency and/or the amplitude of the oscillation and the body shape during the swimming. Several factors will be take account, like the age, the sex, the length, the hunting method, the reproductive status and the body condition, which will allow us to bring out the intra and interspecific variations in the snake phylogeny.

PhD student in ECOPHY team (2021-2024)
Supervisors: Xavier BONNET (CEBC), Anthony HERREL (MECADEV) and Ramiro GODOY-DIANA (ESPCI)
Doctoral school: EUCLIDE (La Rochelle University)
Funded by ANR DRAGON2
Mail : guillaume.fosseries(at)
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