The franciscana dolphin inhabits waters that are sometimes murky from sediments. They locate bottom-dwelling species of fish by echolocation and by digging up the bottom with their long snout. Only a few species account for the majority of the food. In Uruguayan waters the most common fish is Cynoscion striatus . In Brazil, the most common are Paralonchurus brasiliensis, C. striatus, Macrodon ancylodon , and Micropongonias furnieri .
Females eat more squid, Loligo sanpaulensis , than males.
The female dolphin has a breeding cycle of two years. Matings happen from December to February, births from September to December. Females lactate until the following August or September, and then rest for several months. The gestation period lasts from 9 to 10.5 months and lactation can take up to 9 months. Behavior Early weaning, short learning periods, and a solitary life-style could be related to their small brain size, as noted by Kasuya.