A snippet from Gutbloom:

Why don’t whales, that live in salt water and have salt water pass through their mouths, die of thirst?

Why doesn’t the fresh water in a marine mammal’s body flow out into the salt water that surrounds it?

The answer is that marine mammals and fish have a number of adaptations that allow them to conserve fresh water and excrete salt very effectively. It’s not the cod liver oil you want, it’s the cod’s liver. A liver that can filter the ocean must have other uses. If I had a cod’s liver I bet I could drink a keg of beer and piss turpentine. I could pour soy sauce in my miso soup and drink it with a spoon made of anchovies. Oh, to have the liver of a seal!

Read Gutbloom’s post on Medium