Plausible ecology for Hoth?

[Junghalli]

Hooray for the plants. The animals still starve to death.

Maybe the animals can do something similar? They might leave hardened eggs that stay frozen until the thaw, or be able to survive being frozen solid themselves. There are frogs on Earth that can do that. Mind you, I'm not sure how long they remain revivable in such a state, but I imagine metabolism would have to be super-low to nonexistant.

[Darth Yoshi]

Aren't all of the creatures that have a sort stasis-stage exothermic? I'd think that the furred Wampas would have too high a metabolism for that.

[Vultur]

I agree that Hoth probably used to be warmer, with liquid oceans full of photosynthesizing stuff, and this could explain the oxygen. But it doesn't explain the currently existing land life like the wampa.

Maybe *the ice itself*, in the layers closer to the sun, is full of photosynthetic organisms. On Earth endolithic microorganisms live in the spaces inside rock: Hoth sub-ice microorganisms would have the additional advantages of sunlight and more easily available water. Thus, they might well use water as the reducing agent in photosynthesis and produce oxygen. [Not everything that photosynthesizes makes oxygen. Purple sulfur bacteria use hydrogen sulfide instead of water and produce sulfur instead of oxygen.]

In addition, we only see a tiny bit of Hoth and a brief faraway view of one hemisphere. Neither rules out oases existing in warmer areas - perhaps volcanically created, perhaps just microclimates. Perhaps the bluer lines we see on Hoth from far away contain strings of oases, and areas with liquid water under a relatively [centimeters to meters] thin skin of ice?

Another important question: what's a wampa's metabolism? We certainly don't see it moving even as fast as a crocodile could. In fact, it's really slow compared to Earth predators; maybe this means that it doesn't have very high energy requirements and generally eats non-fleeing prey. Thermoregulation would take some energy, but this would be dependent on what its natural body temperature is: if it's 10 degrees Celsius, that would take a lot less energy to maintain than a mammal's would. Also, it clearly uses snow caves to maintain warmth: this is pretty effective even for humans, and it would be vastly better for a creature whose natural body temperature was not as far above freezing as ours.

Perhaps the natural niche of the wampa is a predator of the subglacial lakes that I postulated above? It uses its great strength to bash open the ice, captures slow-moving algae-feeders that live off the algae, and probably eats the algae itself as well. [Its build is pretty bearlike, and bears eat mostly plants. There's no reason to assume it's a pure carnivore.]
Then:
If tauntauns are not native, when tauntauns were introduced to Hoth, it learned to eat them as well - first by feeding off frozen tauntaun-corpses, then learning to attack unsuspecting living ones. By the time of Episode V, some wampas have migrated into areas with no subglacial lakes but plenty of tauntauns: and the movie takes place in one of these.
If they are native, the same more or less applies, but it was a slower process and we have to figure out what tauntauns eat when they're not being fed by humans. Does anything EU say for sure that they *are* native? (I only know the six movies, not the EU). Going by movie evidence alone, I'd have to say they're not: they don't look it.

[Wyrm]

Maybe *the ice itself*, in the layers closer to the sun, is full of photosynthetic organisms. On Earth endolithic microorganisms live in the spaces inside rock: Hoth sub-ice microorganisms would have the additional advantages of sunlight and more easily available water. Thus, they might well use water as the reducing agent in photosynthesis and produce oxygen.

A few problems with this:

First off, it snows. That means that any ice-living alge is going to be quickly buried in snow with some regularity. Snow has a high albedo, so just a few feet of it cuts out much of the solar radiation. This is why most plants up north —where it snows a lot— close shop for the winter. Evergreens are the only ones that don't, and that's because their leaves are adapted to shed snow.

Secondly, our ice-alge may have plenty of water availible, but where's it going to get the other elements it needs to make its light-asborbing pigments? Chlorophyll has magnesium; another photoactive pigment will use another element. Fallen snow is almost entirely pure water... no other elements. (Ice rejects impurities from the matrix when it forms.) So where does it come from?

Furthermore, if we really have acres of snow-alge on Hoth, where's all the discolored ice that should be there? Ice is white because it reflects light. If you want to use light to make sugars, you have to absorb it, meaning that the ice plus alge will not be white in color.

I place no bets at all whether this organism exists somewhere on Hoth, but I'd bet my bottom dollar that its effects are entirely ignorable.

[Not everything that photosynthesizes makes oxygen. Purple sulfur bacteria use hydrogen sulfide instead of water and produce sulfur instead of oxygen.]

Interesting, but irrelevant. Hoth's atmosphere is near enough to Earth's for humans to live there. The photosynthesis we're interested in produces oxygen. We've already pointed out that there are other means of producing sugars besides oxygen-generating photosynthesis.

In addition, we only see a tiny bit of Hoth and a brief faraway view of one hemisphere. Neither rules out oases existing in warmer areas - perhaps volcanically created, perhaps just microclimates. Perhaps the bluer lines we see on Hoth from far away contain strings of oases, and areas with liquid water under a relatively [centimeters to meters] thin skin of ice?

Ice is blue, too. Rayleigh scattering.

Another important question: what's a wampa's metabolism? We certainly don't see it moving even as fast as a crocodile could.

Crocodiles are actually quite quick even by the standards of mammals. A nice, juicy mammal is one of the croc's favorite treats.

In fact, it's really slow compared to Earth predators; maybe this means that it doesn't have very high energy requirements and generally eats non-fleeing prey.

Bollocks. While the wampa is clearly a pouncer, his movements during the pounce do not seem slow compared to a lion or other large predator. The whole attack took about two to three seconds, and the wampa was able to take down two animals during that time. I'd like to see a lion do as well. Furthermore, it's paw is obviously evolved to be a striker — it knocked Luke off his mount with a single strike. That indicates some serious momentum behind it. That takes energy to swing around.

Thermoregulation would take some energy, but this would be dependent on what its natural body temperature is: if it's 10 degrees Celsius, that would take a lot less energy to maintain than a mammal's would. Also, it clearly uses snow caves to maintain warmth: this is pretty effective even for humans, and it would be vastly better for a creature whose natural body temperature was not as far above freezing as ours.

When did the wampa seem slow? When it was walking liesurely towards Luke? At the time, Luke was hung up by his legs, unarmed. In case you haven't noticed, large predators don't run around unless there's prey to be chased.

Also, the wampa has a much thicker coat than Luke, and even with space-age insulators, there's only so much you can do with a certain thickness of material. Yet Luke spent several hours hanging upside down in this cold cave and didn't succumb to hypothermia. Hell, you can be pretty much naked in a snow cave and it'll keep you pretty comfortable. However, if you're perptually in a thick winter coat, moving around with any urgency except for very short periods is asking for heat-stroke. If you're comfortable in cold temepratures while conserving energy, then when you do exert a large amount of energy (such as for hunting), you're going to heat up VERY quickly.

If tauntauns are not native, when tauntauns were introduced to Hoth, it learned to eat them as well - first by feeding off frozen tauntaun-corpses, then learning to attack unsuspecting living ones. By the time of Episode V, some wampas have migrated into areas with no subglacial lakes but plenty of tauntauns: and the movie takes place in one of these.
If they are native, the same more or less applies, but it was a slower process and we have to figure out what tauntauns eat when they're not being fed by humans. Does anything EU say for sure that they *are* native? (I only know the six movies, not the EU). Going by movie evidence alone, I'd have to say they're not: they don't look it.

There was a discussion on this here.