Both the topics of prey-catching mechanism and visual perception are closely connected, affecting each other in many complex situations. The main subjects of this thesis were amphibians and reptiles and the many effects that impact their hunting abilities. We studied their hunting patterns in a few species of frogs and the leopard gecko (Eublepharis macularius) in an arena. We did not find any universal hunting pattern for neither of those groups, moreover even the quantity of individual sequences differed among them. However, hunting in nature is often engaged in habitats that are far from the flat calm arena. Often the animals have to adapt to different conditions, for example an unsteady surface underneath them. In such conditions they need to compensate for the passive movement with their heads and eyes to stabilize the image on their retina. The ability to compensate while hunting in frogs is affecting their behaviour and the success rate of their prey-catching. Another aspect that is influencing frog's hunting efficiency are their protrusible tongues that are commonly divided into three categories: mechanical, inertial and hydrostatic. The last goal of this thesis was looking for the evolution of this trait in frog's phylogenesis and their different effects on hunting movements.

L’océan austral est un écosystème fragile dont la dynamique est influencée par des variations climatiques qui vont structurer la distribution spatio-temporelle des ressources. L’objectif de cette thèse était d’étudier les stratégies d’acquisition des ressources en proies mises en place par l’éléphant de mer austral face aux contraintes énergétiques (coûts du transport et coûts d’accès à la ressource) et temporelles (temps passé au fond d’une plongée et limite de plongée aérobie) auxquelles il est soumis. L’utilisation d’un ensemble d’enregistreurs de données déployés sur ces animaux a permis de reconstruire en trois dimensions leur plongée, mais également de calculer leur effort de nage, le nombre de proies rencontrées ainsi que leur dépense énergétique. Notre étude montre qu’à l’échelle d’une plongée, les éléphants de mer adaptent leur trajectoire, mais également le temps qu’ils passent au fond, en fonction du nombre de proies rencontrées. Pour des densités locales de proie importantes, ils passent plus de temps au fond, et concentrent leur recherche en zone restreinte, caractérisée par une diminution de la vitesse et une augmentation de la sinuosité horizontale. Au-delà de 550 m, le coût d’accès aux ressources devient supérieur aux coûts d’acquisition ; ils doivent alors faire face à un compromis entre l’accessibilité et la disponibilité en proies. À mesure qu’ils s’alimentent, ces phoques augmentent leur flottabilité, diminuant de surcroît leur dépense énergétique. Cette étude démontre également une structuration spatio-temporelle de cette dépense énergétique qui semble être liée au succès d’alimentation et donc à la distribution des ressources en proies. / The Southern Ocean is a fragile ecosystem whose dynamics are influenced by climate change that will structure the spatio-temporal distribution of resources. The objective of this PhD was to investigate the foraging strategies used by the southern elephant seal, under energetic (cost of transport and costs of access to the resource) and temporal (time at the bottom of a dive and aerobic dive limit) constraints. Using a set of animal-borne data loggers allowed us to reconstruct their three-dimensional path underwater, but also to calculate their swimming effort, the number of prey encountered and their energy expenditure. At the dive level, our study shows that elephant seals adapt their path, but also the time spent at the bottom, depending on the number of prey encountered. For high local prey density, they spent more time at the bottom, and concentrated their foraging effort in areas restricted search, characterized by a decrease in speed and an increase in horizontal sinuosity. Beyond 550 m, the cost of access to resources becomes greater than the cost of acquisition ; they must therefore deal with a trade-off between prey accessibility and availability. While feeding, these seals increase their buoyancy, reducing furthermore their energy expenditure. This study also shows a spatio-temporal structure of the energy expenditure that appears to be related to feeding success and therefore to prey resources distribution.