river dolphins have conical teeth, used to catch swift prey such as small river fish. they also have very long snouts, with some measuring , four times longer than most of their oceanic counterparts. they have a two-chambered stomach that is similar in structure to that of terrestrial carnivores. they have fundic and pyloric chambers. breathing involves expelling stale air from their blowhole, followed by inhaling fresh air into their lungs. they do not have the iconic spout, as this only forms when the warm air exhaled from the lungs meets cold external air, which does not occur in their tropical habitats.