Nature or Nurture: Is the Digestive System of the Pontoporia blainvillei Influenced or Determined by Its Diet?

Simple Summary: Anatomy is considered critical to understanding the size and shape of the different systems of animals belonging to the same group or individuals that are close in the phylogenetic scale. In the case of the Franciscana dolphin or Pontoporia blainvillei, the digestive apparatus shows some differential characteristics compared to other dolphins or other marine mammals. In the present work, the authors try to demonstrate whether these characteristics are conditioned by the animal's own diet or if they have more to do with certain phylogenetic adaptations. Considering that the Franciscana dolphin is an endangered species, any work that could facilitate better knowledge of these individuals has a high social, ecological, and scientific value because it will help in their care and conservation, and this is of utmost importance to implement effective management strategies for this species. The Franciscana (also known as the La Plata River Dolphin) is a small dolphin that lives in the coastal waters of Brazil, Uruguay, and Argentina. This species is considered the most endangered marine mammal in the western South Atlantic Ocean. Anatomic dissection of the digestive system of 19 animals of different ages, including 2 neonates, 12 juveniles, and 5 adults, was performed. Parameters related to length, breadth, weight, and diameter of the digestive viscera were considered in each case. Our results show that the Franciscana dolphin presents differential characteristics in relation to several parts of the digestive system, including, specifically, the tongue, the teeth, the stomach, and the small intestine. Thus, this paper add precious information to the actual knowledge of this vulnerable marine mammal species in order to improve conservation efforts.