Because it’s big. So big, it subcontracts parts of itself to the lungs.
I’m afraid I’m not doctor enough to enlighten you. But I can tell you what I know:
It has something to do with breathing, indeed. It gets drained in case of need of oxygen, in order to have more circulating red mass. But this trick should work if you are breathing, thus filling your red cells with oxygen, as far as I know. The more I think about it, the less I understand why this should work during apnea.
Anyway, after a very quick and superficial search I’ve realized that a large spleen is associated indeed with better apneas, and apnea induces splenic contraction. The studies don’t show evidence of better oxygen peripheral availabilty because of this. If splenic contraction improves apnea, the mechanism behind this is not fully understood yet.
I believe that the author of the following Mickey Mouse story is also a Monkey Island fan!


The story has Dutch origin, the drawings come from the American story called “Uncle Scrooge - Shiver me timbers”. https://inducks.org/story.php?c=H+97246
I’d love to see that one!
Ex Interior minister Matteo Salvini while making a Facebook story in Rome. What is he talking about?
Fish. That´s obvious.