system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do aquatic mammals eat food without flooding their stomach with salt water?
gpt
They intake the food, and then blow outwards, spitting the water out of their mouth while keeping the food trapped inside (Humans can do this too. Put something in your mouth, for instance a small bit of carrot, then pour in some water. You can spit the water out through your teeth) The food is then swallowed whole. Excess salt left in the mouth and in the food naturally comes out mainly in their urine, which is about 8 times as salty as land mammal urine. Their blood is about the same in terms of salt content as land mammals.