Na'vi anatomy

[Timelord79 (he/him)]

Just watched Avatar on TV and the Na'vi's anatomy bugged me just as much as the first time.
Every animal on Pandora has 4 eyes and 6 limbs, except the overgrown smurfs.
Did we ever get an explanation for this?
They must be indigenous because they have the ponytail link tendrils, but they must also have seperated dann early in the planets evolution from Most other evolutionary branches to not even have vestigial stumbs.
Doesn't make much sense.
Plus, having four arms seems like a big advantage on a planet where life happens on floating jungle rocks that would be climbed all the time.

 

[Kemaiku]

It's an alien planet. You now, aliens. Not Humans.

 

[Timelord79 (he/him)]

Yeah, but evolution should still apply to aliens. They made it a plotpoint, that Na'vi are an integral part of the plant's ecosystem. And yet they don't seem to be remotely related to anything else living there.

 

[Reverend]

I'm sure if you google it you'll find the official in-universe explanation.

In reality, It's probably just because four eyes and six limbs just looked too alien for the broader audience to be able to relate to. Same basic reason why they're even humanoid at all. A love story would be a hard sell otherwise.

If I had to speculate though, I'd say the Na'vi aren't entirely native to Pandora. Maybe a specially adapted seed species, possibly even part terrestrial hominid. It'd certainly explain the similarities, their relative proximity to Sol and that it's even possible to engineer the Avatars with human DNA at all.

 

[Alidar Jarok]

Just watched Avatar on TV and the Na'vi's anatomy bugged me just as much as the first time.
Every animal on Pandora has 4 eyes and 6 limbs, except the overgrown smurfs.
Did we ever get an explanation for this?
They must be indigenous because they have the ponytail link tendrils, but they must also have seperated dann early in the planets evolution from Most other evolutionary branches to not even have vestigial stumbs.
Doesn't make much sense.
Plus, having four arms seems like a big advantage on a planet where life happens on floating jungle rocks that would be climbed all the time.

Well, we didn't see the entire planet. I can't say humans resemble too many species in New Zealand, yet they're there.

 

[Reverend]

It's not about physical resemblance so much as shared anatomy. For example, while a human looks nothing like a kiwi and evolving half a world away, they're both bilaterally symmetrical, have four limbs (even if the kiwi's fore limbs aren't immediately obvious), two eyes, a cranium and a vertebra. All these features are there because of shared ancestry that is much closer in evolutionary terms than say, a starfish. Even a Shark has most of those features in common, again, because of shared ancestry.

That the Na'vi appear to be the only large animal with two eyes, four limbs and only one tendril link thing means that they're either the result of adaptive engineering, or they're from a very obscure branch of the evolutionary tree. Indeed, the fact that we do see the Pandoran equivalent to primates and they have six limbs and four eyes is very suspicious indeed. In mean what are the odds that two totally separate evolutionary lines, divided by something in the order of a billion years or more and yet ended up co-existing while sharing a very similar yet distinctly separate anatomies?

Imagine if primates on Earth were all hexapods and then try arguing that we're related. Something fishy is going on.

Indeed, hasn't Cameron said that he intends to visit other planets in that system? Perhaps we'll find relatives of the Na'vi on those planets too.

 

[Tosk]

Indeed, the fact that we do see the Pandoran equivalent to primates and they have six limbs and four eyes is very suspicious indeed.

Yeah, but did you notice how the arms were attached to the trunk with a single upper-arm? There's part of your missing link right there. As the mammals have evolved, they ended up with two arms instead of four. That "Pandora Monkey" is the middle step, with two arms on each side that join up part-way.

 

[Mister Fandango]

It's not about physical resemblance so much as shared anatomy. For example, while a human looks nothing like a kiwi and evolving half a world away, they're both bilaterally symmetrical, have four limbs (even if the kiwi's fore limbs aren't immediately obvious), two eyes, a cranium and a vertebra. All these features are there because of shared ancestry that is much closer in evolutionary terms than say, a starfish. Even a Shark has most of those features in common, again, because of shared ancestry.

How about some of these completely terrestrial creatures that all evolved right alongside humans? Let's see, there's the leafy seadragon, the hagfish, just about any species of octopus, most mult-eyed multi-armed insects, and tons of others.

Sure, you can claim a starfish is similar to humans, but you'd be about as wrong as you are about the na'vi and the rest of Pandora, mostly because any evidence you have is superficial and based solely on what you see on the screen. No dissections. No detailed scientific journals. Just a few pictures of them running around, about as accurate as looking at a human right next to the aforementioned starfish (or any of the examples above).

In other words, the na'vi are clearly the freaks of Pandora, and they probably do share those treats but, for whatever reason, they evolved away from them and they became recessive, redundant, or simply concealed in some fashion.

You know, kind of like our tails. Or most of our fur.

 

[YellowSubmarine]

I've wondered over this question, and I was told that they evolved from these four-armed creatures that jumped from tree to tree that Perseus nearly shot in the forest. I would take it their four arms merged into two over time. Perhaps that gives them additional strength too.

My pet explanation is that they did not evolve together with the rest of the creatures, and/or that ponytails aren't evolutionary traits, but a product of genetic engineering. I don't see natural USBs and Internet evolving through natural selection as that plausible (certainly less than four arms merging into two). Though I must admit, I had heard that idea before, and I was extremely fascinated by it, so seeing James Cameron put it in his film was a pleasure, plausible or not. I was actually contemplating how it might happen at some point, almost convincing myself that it could.

 

[FPAlpha]

First.. Nav'i are not primates i believe, from the looks of it they're probably descendent from a catlike species.

However that doesn't matter much because, as someone had already mentioned, reality of movie production meant that having 4 (or more) eyed, six limbed humanoids might be ok but if you want a romantic storyline in there between a human and a Nav'i it would have been too freaky for mainstream audiences.

Them being cat-like humanoids with tails was pushing it but safe.

Maybe they will try and explain that in the sequels but i bet they won't as it most likely will not be important to the rather simple storyline.

 

[GalaxyX]

I don't get the praise this movie gets.

Boring plot, derivative story (reminded me of a cross between Ferngully: The Last Rainforest, and Dances with Wolves). The characters were cardboard cutouts. It was fucking preachy to the max, and the supposed highlight of the movie (the purdy graphics) seriously made me feel like I was watching someone else play an extended session of Crysis Warhead at full blown maxed out graphical settings (I have a GTX 690 on a 27" monitor, so I know what that looks like )

Way overrated IMO.

 

[YellowSubmarine]

If we're talking about an alien biosphere, orders like primates or families like felids would be rendered nearly meaningless to begin with. There won't be primates, there won't be fish or birds for reasons similar to why a dolphin is not a fish and a bat is not a bird. The dolphins might have fins and look like fish, but they aren't genetically related to be ones. On another world nothing is genetically related to anything on ours, so nothing is ever a fish. If something is dead similar, you might have xenofish or something, but unless convergent evolution is a very real and an all-encompassing phenomena, the clads on the alien world would be totally unlike ours, so you wouldn't even be able to draw parallels.

On the other hand, convergent evolution with respect to specific traits and general appearance seems to be a thing, at least to an extent, even within our biosphere where you have huge variation between relatives, and at the same time similarity between very distant branches. We've mistaken the evolutionary link between species more than once – we mistook dolphins for fish, and never realized chimpanzees were our closest cousins. So if something that looks human evolved from a cat and not a primate I wouldn't be at all surprised. There's no specific reason why a cat can't evolve into something naked, with human posture, real arms with hands, and feet suitable for walking upright.

But yeah, I share your opinion that they made them too human for that to be believable if you're going to be too strict, but at the same time they gave them enough non-human features for the casual watcher to feel they aren't. Works for me.

What I can't get is why creatures that aren't mammals (yeah, they aren't) have boobs. And then people complain about Carol Marcus' underwear. She's human, nothing so surprising about her body to see there!

 

[Venardhi]

I'm pretty sure I made the same comment when I first saw it and it is still a bit annoying. If the native Na'vi had 4 limbs and the human hybrids only had 2 it would have made for a nice contrast and given good reason for them to see him as lesser. The attempt to bridge the evolutionary gap with the double-forearmed cat monkeys was weak tea, but in the end I think it came down to making them look as anthropomorphic and thus as sympathetic as possible.

 

[Reverend]

Indeed, the fact that we do see the Pandoran equivalent to primates and they have six limbs and four eyes is very suspicious indeed.

Yeah, but did you notice how the arms were attached to the trunk with a single upper-arm? There's part of your missing link right there. As the mammals have evolved, they ended up with two arms instead of four. That "Pandora Monkey" is the middle step, with two arms on each side that join up part-way.

I had a similar thought and if you look at the primate equivalent lemur looking thing I mentioned, the four arms are pretty much the only basic difference. I was going to mention that the Na'vi appear to be the only species I notices with hair, but as you can see this thing has a little downy ridge. It even has two eyes without so much of a vestige of the smaller pair of eyes. So it looks like the Na'vi aren't the only species that are drastically different and where there's two, there's probably a whole family of species.

Still strikes me as a little odd though. Yes I know you can't make direct 1:1 terrestrial comparisons, but you can apply certain patterns of evolution. Specifically that for as long as there have been life on Earth, it's been divided up amongst fairly narrow lineages. For example the reason why we mammals share a basic anatomy with fish, reptiles and birds is because we evolved from the same species that first crawled out of the sea. We've inherited all the evolutionary "choices" up until that point and built on them. It's why we have five fingers and not three or eight because that's how many bone digits said fish had.

So to my mind, for the Na'vi and what looks like a member of the same family (order? kingdom?) of species to be so divergent from the rest, they either split off from the other large animals *very* early, or their ancestors have been tampered with somehow.

Ultimately it's just a little odd that Cameron introduced what looks like a deliberate inconsistency, I have to wonder if he has a story idea that'll compliment it.

I don't get the praise this movie gets.

Boring plot, derivative story (reminded me of a cross between Ferngully: The Last Rainforest, and Dances with Wolves). The characters were cardboard cutouts. It was fucking preachy to the max, and the supposed highlight of the movie (the purdy graphics) seriously made me feel like I was watching someone else play an extended session of Crysis Warhead at full blown maxed out graphical settings (I have a GTX 690 on a 27" monitor, so I know what that looks like )

Way overrated IMO.

And I don't get why people get so bent out of shape over it. It was a highly archetypal story straight out of Joseph Campbell's monomyth, well acted and well presented. Nobody anywhere, not the critics who praised it or even the people who made it claimed it was Shakespeare. Wasn't trying to be. It was just a very well done *fun* adventure film of a sort that hardly ever gets made any more. Mostly it just known as the first (and AFAIK so far pretty much only) film to do 3D well. Mostly, it was just refreshing so see a film with some colour!

OK so it had an environmental message in there too. So what? It's more that most blockbuster films can say and it's a message that served the story, not the other way around. Also, it's hardly irrelevant because this kind of crap it still going on right now and hardly anyone even notices.

Like a lot of simple adventure films, what held my attention beyond the opening credits was the seemingly well thought out and reasonably detailed world Cameron came up with. Not unlike Star Wars in that regard.

Sure, you can claim a starfish is similar to humans...

Uh...where exactly did I claim this? I'm pretty sure I said the exact opposite; that they're completly anatomically dissimilar. You'd have to compare the DNA to prove humans are related to starfish--which, before anyone else decides to misinterpret me, yes of course they are. The point being that the point of divergence between humans and starfish is in the order of billions of years while the divergence between humans and other mammals is more like tens of millions. I'm also not say that the Na'vi and other Pandoran species are quite *that* far removed, but the fact remains that a human has more in common with a coelacanth than a Na'vi with a direhorse.

 

[JarodRussell]

We have eight legged spiders, six legged insects, etc... It's just on our planet that the ratio of 4-legged animals to multiple-legged animals is pretty high. Maybe that whole evolutionary branch of 4-legged animals on Pandora just got eaten up by all those 6-legged freak creatures. And the Na'vi survived because, well, they learned how to throw spears.

Or they have leftovers of the other two legs in their pants. And they get cut off in a weird cruel irrational religious ceremony just after birth.

 

[Reverend]

We have eight legged spiders, six legged insects, etc... It's just on our planet that the ratio of 4-legged animals to multiple-legged animals is pretty high. Maybe that whole evolutionary branch of 4-legged animals on Pandora just got eaten up by all those 6-legged freak creatures. And the Na'vi survived because, well, they learned how to throw spears.

Or they have leftovers of the other two legs in their pants. And they get cut off in a weird cruel irrational religious ceremony just after birth.

Yeah, but again, the ancestral divergence between humans and arachnids is MUCH more significant than humans and other mammals, or even reptiles in this case. If memory serves, spiders are descended from some kind of cambrian period arthropod.

Hell, the eight legged things is the least of the differences. Spiders don't even have skeletons.

The point most of you appear to be missing is that the Na'vi are so outwardly similar to most of the other species we saw, but there are a few pretty fundamental differences that makes it look like something screwy is going on.

It'd be like if there exists on Earth a species that looks just like a centaur. There's just no logical place for it on the evolutionary tree. Ironically the creationists would love such a discovery.

 

[Mister Fandango]

Yeah, but again, the ancestral divergence between humans and arachnids is MUCH more significant than humans and other mammals, or even reptiles in this case. If memory serves, spiders are descended from some kind of cambrian period arthropod.

Many species of monkeys have tails. Humans don't appear to. There's tons of five-limbed monkeys, yet humans only have four?! OMFG, how can this possibly be?! They're clearly related, yet five > four?!

Most mammals are covered head to toe with fur. Humans have very, very little. OMFG!

Dolphins are mammals, yet... they live in the water?! And have fins instead of arms and legs?!?! AHHHHH!!! MY BRAINZ!!!

Also, alien world with zero -- that's zip, nil, zilch, nada single bit -- of genetic information, evolutionary paths, or biological history available to the audience. Just a few random animals you assume to be closely related to the na'vi (no matter how wrong you are) from a tiny and completely insiginificant sampling of that alien world.

 

[Alidar Jarok]

Yeah, pretty much. I even posited the theory that the Nav'i come from a different part of the planet originally so things that might look similar aren't there (although that monkey-like thing could be closely related, in which case I would likely be wrong about that theory, but that doesn't mean we have enough knowledge of their species to make an informed decision).

 

[Tyberius]

The Na'vi, or any other 4 limber, could have also came from the other planet in the system during a period of close orbit and unobtanium upheaval.

 

[Reverend]

Yeah, but again, the ancestral divergence between humans and arachnids is MUCH more significant than humans and other mammals, or even reptiles in this case. If memory serves, spiders are descended from some kind of cambrian period arthropod.

Many species of monkeys have tails. Humans don't appear to. There's tons of five-limbed monkeys, yet humans only have four?! OMFG, how can this possibly be?! They're clearly related, yet five > four?!

Most mammals are covered head to toe with fur. Humans have very, very little. OMFG!

Dolphins are mammals, yet... they live in the water?! And have fins instead of arms and legs?!?! AHHHHH!!! MY BRAINZ!!!

Also, alien world with zero -- that's zip, nil, zilch, nada single bit -- of genetic information, evolutionary paths, or biological history available to the audience. Just a few random animals you assume to be closely related to the na'vi (no matter how wrong you are) from a tiny and completely insiginificant sampling of that alien world.

First off sunshine, calm down before you strain something.

Secondly, we *do* have vestigial tailbones along with a number of other vestigial organ structures. Just like dolphins have distinctly mammalian features, like for example lungs and a forward bending spine. Incidentally we have just as many hair follicles as our simian relatives, they just don't all grow as long any more. A species may be adapted for it's environment, but it's form of adaptation tells the story of how it got there.
Now while it's certainly possible that the Na'vi's forelimbs fused, I have a slightly harder time believing that a pair of eyes would just disappear leaving behind no vestige that they were ever there.

As for the lemur looking thing, I'm not assuming anything. I'm pretty sure the filmakers said it was designed specifically to try and bridge the anatomical gap between the Na'vi and the other Pandoran fauna. Do try and remember that we're talking about a fictional world, yes? If something is there, it's because it was designed that way and the filmakers have a reason for it being there, even if that reason is purely aesthetic.

The Na'vi, or any other 4 limber, could have also came from the other planet in the system during a period of close orbit and unobtanium upheaval.

I'm not adverse to the idea, but it doesn't quite gel with what we see. As I've said already, it's not the differences that bug me, but the similarities. It's a bit of a paradox and I'm interested to see if Cameron takes it anywhere.

Just the very idea that human DNA could be successfully spiced with a Na'vi means that there's some very fundamental similarities that simply shouldn't exist between two species that evolved on separate planets. Put simply, we'd have a better chance of breeding with a tomato plant.

So either Cameron is going somewhere with this and it'll turn out Terran and Pandoran life share some common ancestry, or it's just made-up sci-fi mumbo jumbo and it doesn't mean anything. Probably the latter, but it's fun to speculate.