Really far away from space in the realms of Disney* Fairytales...

[Whirligig Girl]

So I was thinking about oceanic biology, and I recall that I remember hearing that Humans may have at one point been in the water a lot. We have slightly webbed hands, Wrinkled fingers let us hold on to slippery things better, etc. I thought about Mermaids. Is it even slightly possible that humanoid creatures could exist*? Clearly not. Although, it could make an interesting plot to a Sci-Fi story, albeit with "Artist's License: Biology". Fantasy is fine for little kids and fairy tales, but I wonder if any serious Speculative Science Fiction Stories have ever been written about "Mermaids". What I wonder about even more is if the Rocket Scientists that browse these forums even give a crap about Speculative Marine Biology, Fantasy, or Disney films*

*Joke

[Camacha]

I found this theory somewhat fascinating when I heard about it, as it does make a fair amount of sense. And of course, it is wildly opposed and ridiculed by the status quo of that scientific area, which is one of the better indicaters it might be right

[LaydeeDem]

It's fascinating to think about. But it has just about as much science behind it as the electric universe. It's a thought with no testing behind it.

It doesn't help that that mermaid mockumentary was aired and people actually believed it. Then again, animal planet has a show that consists almost entirely of people hearing a noise in the woods and getting spooked by the scary scary squatch in the woods. 2spooky4me

[Awaras]

Is it possible for an aquatic hominid species to exist? Sure. Do they exist? Well, if they did, they would be at a similar stage of water adaptation as, say, seals. Not enough time has passed for them to make a full adaptation on the level of dolphins for example. This would mean that they would spend a lot of time on shores and beaches and we would have probably found them by now...

Or, as you say, they might have changed their minds, went back to dry land and became us instead.

[Ralathon]

I heard about this theory as well, but I don't give it too much merit.

Most of the reasons it gives are easily explained via other routes or just plain wrong:

Humans have no fur: Yes we do, it's just much scarcer to allow us to sweat. Humans are actually one of the best long distance runners in the animal kingdom, aboriginals hunt by running after prey until it drops from exhaustion. If the track is sufficiently long a human can outrun a horse with relative ease. When you run for long durations heat management is absolutely essential, which is why we're one of the best at sweating. Hair also has nothing to do with aquatic species, platypus and beavers show that fur and water mix quite well.

Humans are bipedal to avoid drowning in shallows: Could be yea, but it seems way more likely that it evolved to give us a better vantage point on the savanna and to free our hands for tool use. Both of those explanations are scientifically supported by the fossil record since we can find the hand axes they used all over Africa.

Humans have big brains because other aquatic mammals also have big brains: Chimps have big brains and they hate water, correlation does not imply causation. Not to mention that the timescales are way off, our ancestors became bipedal a few million years ago and we only started to really pump up our brain volume a few hundred thousand years ago.

etc. The hypothesis is sketchy at best and downright wrong at worst, I wouldn't trust it until they come up with some real evidence.

As for an aquatic human species. I doubt that they'd look anything like a mermaid. That tail seems very unlikely to evolve since it means you have to radically alter the bone structure of the lower body. If something like that had time to evolve it would certainly have streamlined our shoulders and face. Those cause a lot of drag when swimming. Humans that adapted to an aquatic environment would probably swim like frogs and look like murlocs.

[Whirligig Girl]

I always thought a real mermaid would look more like Harry Potter in that one book where he has to go underwater to win some tournament, and he gets frog-like limbs.

[Godot]

Of course there are aquatic humans ... have you never seen the documentary series "Man from Atlantis" with Patrick Duffy?

(but well .. in reality I don´t think it would make much sense ... humans aren´t very well adapted for a life in the ocean (even if we disregard the lack of gills) ...

just look how many adaptation the only land vertebrate to return to the water underwent ... the whales)

Edited December 22, 2013 by Godot

[lajoswinkler]

Sorry to burst your bubble, but it's not a theory because there is no evidence for it. Theories are explanations backed up with empirical data.

It's not even a hypothesis or a proposition. It's a notion. It's interesting from a fantasy standpoint, but that's it.

Today it's more about examining genes than leftover bones, and none of that even implies there were aquatic hominids. Such thing would be a huge deal. It requires lots of time for adaptation (think about dolphins), but all we have is evidence that our ancestors were on dry land and the time spans included weren't so great compared to what happened with dolphins.

[Whirligig Girl]

Will edit it as a hypothesis. I feel so stupid for mixing those up.

EDIT: I never called it a theory.