I wonder which would actually be more effective. I mean, usually fish ingest water through their mouth to pass over their gills. But that doesn't seem to be the case here. Okay, it's 1:30 am and I'm thinking of the operating principles of fictional biology. I should really go to sleep. Incidentally water maxes out at around 5% dissolved oxygen. So you'd have to move at least 4 times the volume as air, assuming the same capture rate. Water is around 800 times denser than air so you'd be moving about 3200 times thd mass.
Zesc
May 13, 2026 8:52AM
^ To indulge in sweet, sweet ultracrepidarianism:
Per Wikipedia, human capture rate is only 20 - 25%, whilst gills can reach up to 90% efficiency. So the volume is prolly the same. Of course the density disparity remains, though aquatic respiration has the benefit of ram ventilation (i.e. moving through the medium absolves you of having to pump it). That'd might also imply she has both types of gills.
Additionally, we can't know if Waggy-Saggy has the same oxygen requirements as land dwellers. Even mammals can hold their breath for multiple hours by dialling back their metabolism, and since she canonically overwinters beneath the frozen lake, she likely can do with less.
No, the important question is: does her lung function as swim bladder? They're homologous, after all. But that probably means she can't speak or give underwater kisses whilst diving. Sad, science ruined another fantasy.
Nonna_SoF May 5, 2026 1:40AM
I wonder which would actually be more effective. I mean, usually fish ingest water through their mouth to pass over their gills. But that doesn't seem to be the case here. Okay, it's 1:30 am and I'm thinking of the operating principles of fictional biology. I should really go to sleep. Incidentally water maxes out at around 5% dissolved oxygen. So you'd have to move at least 4 times the volume as air, assuming the same capture rate. Water is around 800 times denser than air so you'd be moving about 3200 times thd mass.
Zesc May 13, 2026 8:52AM
^ To indulge in sweet, sweet ultracrepidarianism:
Per Wikipedia, human capture rate is only 20 - 25%, whilst gills can reach up to 90% efficiency. So the volume is prolly the same. Of course the density disparity remains, though aquatic respiration has the benefit of ram ventilation (i.e. moving through the medium absolves you of having to pump it). That'd might also imply she has both types of gills.
Additionally, we can't know if Waggy-Saggy has the same oxygen requirements as land dwellers. Even mammals can hold their breath for multiple hours by dialling back their metabolism, and since she canonically overwinters beneath the frozen lake, she likely can do with less.
No, the important question is: does her lung function as swim bladder? They're homologous, after all. But that probably means she can't speak or give underwater kisses whilst diving. Sad, science ruined another fantasy.