Dolphins, like other marine mammals, don’t drink the water they swim in. Marine fish must drink seawater all the time, and the more salt they have, the more water they must drink. Their kidneys cannot cope with the high amount of salt in seawater.
Dolphins may drink water, but they do not drink seawater, because seawater is too salty and filled with bacteria. Instead, dolphins acquire water from their food and the occasional freshwater they might encounter. This means that dolphin blood is much less salty than ocean water.
Despite the habitat of marine mammals, the level of salt in fish that feed on marine mammals is two-thirds lower than the salt level in the ocean. Many marine mammals can handle high salt concentrations in seawater without becoming dehydrated from salt buildup, as humans would. Thus, marine mammals regulate their water intake with their food, while seabirds and reptiles can drink salt water but excrete it through special glands.
This applies to all marine mammals such as whales, dolphins, seals, and so on. They get water through food. However, for most whales and dolphins, we simply don’t know how they get their water because these animals are difficult to observe. Scientists are somewhat unaware of the feeding habits of whales and some dolphins, as they are difficult to observe in the wild.
All Sea Mammals Must Drink Water
Some seals and sea lions drink seawater at least occasionally, as do common dolphins and sea otters, but the practice is very rare in some other species. Some marine mammals are known to occasionally ingest seawater, but rely on other options, explained marine biologist Robert Kenny of the University of Rhode Island.
In fact, a study of California sea lions showed that feeding on fish, these animals can survive without fresh water. Some seals eat snow for fresh water; meanwhile, California sea lions get enough water from the fish they eat and can survive without fresh water.
Whit whiskers do not lose water through sweat like we do, and therefore require less water in their diet than we do. It would seem that dolphins and whales are surrounded by water, but drinking salt water, on the contrary, will lead to dehydration and death. They may survive for a while, but they will be exhausted (because they have less buoyancy in fresh water) and after a while their skin will begin to peel off (like our skin after a long bath).
Why Humans Can’t Drink Sea Water
People can’t drink sea water because we can’t make urine saltier than sea water, so we waste more water to get rid of the salt. One of the most annoying ironies about human life on Earth is that our life depends on water, yet 96.5% of all water on Earth is sea water, which we cannot drink.
Dolphins urinate in the water they swim in, making it difficult to measure their diuresis. For example, bottlenose dolphins can change the concentration of their urine when moving from salt water, their natural habitat, to fresh water.
Because all mammals (including dolphins) require the consumption of fresh water to survive, dolphins are thought to have an advanced filtration system that allows them to extract additional salt from their urine to separate the salt from the salt water they consume. DOLPHINS and other marine mammals can obtain water from food and produce it internally through the metabolic breakdown of food.
Marine Animals Can Tolerate Salty Water
The body of most marine mammals is designed to absorb water through the metabolic breakdown of carbohydrates and fats through digestion. Seals and dolphins are able to catch, process and swallow food under the waves.
Dolphins don’t use their teeth to chew, they use them to take in food and then swallow it whole. To prevent the captured prey from flying away before it is swallowed, seals and dolphins suck food deeper into their mouths by pulling their tongues back. Suction filter feeders then filter small prey, such as krill, from the water sucked into the mouth.
Other characteristics of dolphins that make them mammals rather than fish are that they give birth to live pups instead of laying eggs and feeding their pups with milk. Most newborn dolphins, nicknamed calves, arrive during the warmer season, although the animals can give birth to calves at any time. The whales and dolphins were rarely seen for more than a few minutes watching their mother drink.
Some Notes on Dolphin Diets
In addition to squid and other cephalopods, smaller dolphins eat fish such as sawfish, herring, cod, and mackerel, among other species. There are over forty species of dolphins and they live in a wide range of environments, from freshwater rivers, estuaries and coastal waters to deep oceans. Unlike fish, which breathe through gills, most dolphin species breathe air through their lungs. On average, an adult dolphin eats fish in the amount of 4-9% of its body weight per day.
Despite their apparent differences, all mammals appear to follow only six well-defined, interconnected, and increasingly specialized aquatic feeding strategies. In this study, we originally intended to consider the feeding behavior of all carnivorous aquatic mammals: creatures as diverse as the brilliant otters, seals and agile dolphins, as well as filter whales.
