Practicality and gilled humans

[nancylebov]

dglenn quoted merde:

this naturally led to thoughts of how silly it is that when superheroes or other humanoid characters with gills are portrayed in film, art, etc., the gills are always placed on the neck. this makes no sense at all, since gills of that size would be much too small to collect sufficient oxygen for an organism of that size. it would make much more sense to put the gills on the chest or back. it'd look way cooler, too.

and that led to 1) a story idea, and 2) the realization that soon after medical science made it possible for humans to have gills, someone would want to get theirs pierced.

And I LOLed, because I was suddenly hurting in a body part I'd never thought of having.

merde continued:

and then there's the skin thing. you couldn't have the gills covered in the water, so you couldn't wear a traditional wetsuit. you could of course have one with a cutout, but that would rather reduce the efficacy of the insulative properties. so you'd need to come up with some way for people to stay warm, too. and to protect their skin. scales probably wouldn't appeal to most people, since they'd be scratchy and unpleasant to snuggle up with. you could apply an insulating slime layer before going in the water, but it'd get scraped off too easily and wouldn't protect against abrasive surfaces. so i'm still thinking on that one.

I don't think there's a simple solution-- it's not just a matter of exterior exposure, you're pumping quantities of chilly water into your body. There may be practical reasons (not just a matter of evolutionary pathways) why there aren't any warm-blooded creatures with gills.

I tentatively suggest cold-blooded humans with some sort of metabolic tweak to keep the brain warm.

What's the earliest sf saying that bioengineering involved metabolic changes as well as visible changes?

"Lift goes by the square of a given dimension; dead load by the cube of the same dimension, other things being equal. I might be able to make you a Pegasus the size of a cat without distorting the proportions too much." ----Heinlein, "Jerry Was a Man"

Comments

[chickenfeet2003.livejournal.com]

Would blubber not be the obvious answer to the insulation problem?

[inquisitiveravn.livejournal.com]

Umm, actually that fails to get around the fact that the water has to pass inside the body. Although I suppose brown fat might help. The real problem though is getting enough oxygen to fuel a mammalian metabolism at all.

[inquisitiveravn.livejournal.com]

Actually, you'd be piercing the operculum or for a cartilaginous fish, the gill slits which are actually just breaks in the skin that allow water to flow out of the gills which are themselves purely internal.

As for the cold blooded humans with metabolic tweaks, great white sharks and a few other fish already have such tweaks in the form of a sort of vascular heat exchanger. One might be able to do something similar in humans.

I do recall reading a science fiction novel many years ago that actually had a long discussion of the feasibility of human gills and concluded that it just wouldn't work. The big sticking point was just getting enough oxygen from the water. The solution was to not bother with gills and use a hyperoxygenated fluid a la The Abyss, although the book predated The Abyss by at least a decade. Now if only I could remember the title...

[captain-button.livejournal.com]

The breathable fluid was around long before The Abyss, I recall seeing a rat breathe it in a commercial in the 1970s. But there are a bunch of problems with divers using it, including that if it isn't kept at body temperature it will suck the heat out of you quickly.

There's a Wikipedia page, of course:

http://en.wikipedia.org/wiki/Fluid_breathing

It of course pointed out that Joe Haldeman had this in "The Forever War", which I should have remembered.

Hal Clement used it too, it seems.

[inquisitiveravn.livejournal.com]

Umm, I did point out that the novel I read was published before The Abyss by at least a decade. It is apparently not one of the fictional examples mentioned in the Wikipedia article, though. Too bad, I was hoping to find out what the title was. I just used The Abyss as an example that most folks would recognize.

Now that I think about it, temperature was also a major issue for water breathing.

BTW, OT, were you a member of the RPGAMES forum on Compuserve in the 80s and 90s? Well known for button mail.

[captain-button.livejournal.com]

BTW, OT, were you a member of the RPGAMES forum on Compuserve in the 80s and 90s? Well known for button mail.

Yup, that's me.