why are dolphins and other sea mammals able to deal with seawater whereas any seamen would rather die of thirst than drinking only one cup of saltwater

Question

What is there essential difference? Is there some kind of filter and if so, where and how does it work?
And what about other fish? Do they employ the same mechanism? And seaweed and stuff?
My basic understanding of living cells says that much salt does much harm, therefore as far as I’m concerned, there should be no living cell in the whole wide ocean.
Also interesting: how do eg salmons perform the transition between sweetwater river courses and their long mating routes across the ocean?

In: Biology

Answer 1

There is not much research on this so good question

Their kidneys are super cleaners compared to ours.

Also scientists say they get their water from the food they eat…. this is debatable as many whales migrate long distances and food is not always readily available.