How does octopuses drink water?

If you have ever been in the sea for a long time have you ever noticed that your skin plumps up? Or if you are in fresh water like a bath have you ever noticed how your skin wrinkles.

These effects are caused by an effect called osmosis. Osmosis is when molecules of a solvent to pass through a semi-permeable membrane from a less concentrated solution into a more concentrated solution. Well that's the technical description.

Fish, molluscs and even Octopi who live in the sea have a huge problem. Their internal fluids are Less dense than the surrounding sea water. So they need to minimise their water losses and balance salt intake because the sea is leaches water from their bodies by osmosis. So to combat osmosis they don't urinate much and they have to have a way of reducing salt.

With fresh water fish the opposite is true they gain water all the time through their skins so they urinate all the time and don't need to drink. Their problem is the exact opposite of the Salt water organism.

So do Octopi get thirsty? Probably as its likely that they need to drink sea water and process it constantly.