Dietary patterns of Yacare in the wetlands of Corrientes, Argentina

Abstract We investigated the feeding habits and dietary patterns of Yacare ( Caiman yacare ) in freshwater wetlands located in the province of Corrientes, Argentina, with a focus on how these habits relate to the size of the caiman. A total of 39 caimans were classified into different groups based on their total length, including hatchlings (Class I), juveniles (Class II), and adults (Class III and IV). Stomach contents were obtained through gastric lavage. Insects (Coleoptera, Orthoptera, Odonata, and Hemiptera), mollusks ( Pomacea sp. ), and freshwater crustaceans ( Pseudopalaemon sp. and Trichodactylus sp. ) were the most common prey, while reptiles, fish, and birds were less frequently consumed. Remains of aquatic plants such as Pistia sp., Azolla sp. , and Elodea sp. were also found. Prey diversity and diet composition were similar across the size classes of caimans. As the size of C. yacare increased, smaller prey were not excluded in order to consume larger prey. Larger caimans had larger Pomacea sp . opercula in their stomachs, potentially linked to morphological constraints, such as the limitation in jaw opening. Our findings suggest that Caiman yacare incorporates a variety of prey into its feeding behavior, and there is no abrupt change in dietary pattern as the caimans grow in size.