- According to the San Diego Zoo, dolphins gain all of their water from the bodies of the fish they eat. Dolphins share this adaptation with some species of land-dwelling desert mammals.
- Like other fully aquatic mammals, dolphins require very little water for survival. Their bodies are efficiently designed---unlike land mammals, they have no need to sweat and produce very little urine.
- In times of deprivation, many mammals suffer from the effects of dehydration long before they are affected by starvation. Because of dolphins' biology, they are unlikely to ever suffer from dehydration.
- Lactating mother dolphins produce a thick, dense milk that is nearly solid; this produces enough to meet the needs of a growing calf without depleting the mother's water reserves.
- Some rare species of dolphin, including the Amazon river dolphin, actually live and thrive in freshwater ecosystems. They may drink water while eating or playing.
