Yeerk physiology

[Yarin]

how does the Yeerk body work? discuss here

[JFalcon]

Do you men how do they flaten themselves/liquify to take control? Or do you mean things like how do they expell waste, how do they absorb Kandrona rays, or how do they manage to avoid accidentally reproducing like amebas when they're pakced thousands into a pool?

[Yarin]

all of those things

[goom]

we don't know
i'm not even sure how they tighten themselves up enough to fit into the human ear..
or how they wrap around the brain?

what was the size again? about 6 inches? (a 'large slug', i remember)

[JFalcon]

I have to admit I at one point wondered how Yeerks could get from the ear to the brain without, you know, cuasing the host to go deaf in that ear. The books used to say that the Yeerks could liquify when sinking into the brain so it would have made sense that they could pass through the ear like liquid too, but later it just says that they flaten like pancakes on the brain squeeze their way through the ear, secreting painkilling substances to keep the host from feeling pain--even though Jake did, but that makes sense because there's no reason to think the Yeerks pain-killers would work on humans who evolved on a whole different planet than the yeerks . . . still how do you not suffer some long term damage when a giant worm pushes its way from your ear to your brain? people go deaf from q-tips for crying out loud. Whether or not it has painkillers shouldn't matter,the fact is a six inch alien is squeezing through your narrow ear cannal into your skull, into your brain.

[goom]

also, i've wondered if yeerks are able to make it from the ear to the brain, how can they be squished (like visser one)?
that shouldn't be possible.

[JFalcon]

. . . how did they first realize they could enter brains at all I wonder, I mean did one day, a Gedd show up at the Yeerk pool flinging not-mud at his fellow Gedds, laughing and having a generally good time, then fall into the pool irritating the surly Yeerks who then decided "You know what? Let's squeeze into his ear and mess him up right good" as punishment then suddenly, to their utter shock they were in control of the Gedd body?

The Gedds couldn't have been stupid enough to just go around sticking their own heads into the Yeerk pools, at some point some yeerk must have figured out he could get into the head, must have found a way to force the Gedds to let his brother and sister yeerks in as well.

[goom]

it was convenient that the species had ears/entryways.

[JFalcon]

I'd almost call it Crayak manipulating the evolution of the yeerks by introducing that first adventurous yeerk to that first filthy Gedd ear, but he already had his Howlers, I don't think he felt like they needed little brothers.

[Loligo]

. . . how did they first realize they could enter brains at all I wonder

Parasitism is innate...instinctua l. You might as well be asking how tapeworms or roundworms realise that they can get into the intestines of their hosts. My guess is that you're right, some unsuspecting Gedd fell into the Yeerk pool, instinct took over, and the rest is history.

[DinosaurNothlit]

To answer the Gedd question, the books have said that Yeerks and Gedds co-evolved, as sort of a symbiotic species.  Gedds are, I believe, not even sentient without a Yeerk in their brain, so it was actually to their evolutionary advantage to, well, fall into Yeerk pools.  And it's obviously to the Yeerk's advantage, too, to have a body.  Whenever there's an arrangement that both species benefit from, evolution finds a way to make it happen. 

It was probably somewhat gradual.  Gedds probably evolved to start sleeping with their ears near Yeerk pools, while the Yeerks gradually evolved to reach tendrils deeper and deeper into their heads, and eventually went in with their whole body.  It's not like a Gedd could have just fallen into a Yeerk pool, where there was a Yeerk waiting for him that was already magically adapted for taking over his brain. 

As for how Yeerks get inside peoples' ears without rendering them deaf, I always wondered that too.  Maybe they make sure to use the same ear every time, so at least they're only deaf in one ear?

[JFalcon]

Well that's actually possible, the only ones whom we see experience "yeerkery" firsthand are Jake and Cassie, both of whom could have simply healed their ears with morphing. 

[Aquilai]

Yes I'm sad enough to turn the possibly rhetorical questions to semi-realistic answers.  Semi in this case meaning as far as I can stretch my scientific imagination. Also I'm going to ignore that Animorph's is just purely fictional so magical answers similar to it-just-does doesn't exist.

Do you men how do they flaten themselves/liquify to take control?

We know they can compress themselves (obviously to move around) it's possible that their bodies are highly compressible which suggests they can range from large to mini (smaller than an ear hole in width and height) which seems quite ludicrous. It's possible that their apparent large size (relative to an earhole) is mostly due to something that they can expel like some form of gas which would require some solid/liquid to gas conversion before shrinking to earhole size. The conversion is required otherwise their density would suggest they can virtually float in air or jump immense heights which apparently they can't.

To take control another theory is that only a small part of their body is the nucleus/brain and an extremity/limb of thin (possibly liquid as the books suggest) layer is extruded to filter through the brain crevices and intercept the synapses to redirect thoughts and actions. It would have to be either liquid or an immensely thin membrane to slip tendrils into all parts of the host brain.

how do they expell waste

What makes you assume that an alien race has to expel waste? Perhaps their recycling system is more advanced than our own. As with the first question some conversion could take place so that all waste are of small gaseous/liquid quantities so virtually any part of the body can be used to expel excretion.  (Although I maybe talking complete ....)

how do they absorb Kandrona rays

How do you absorb x-rays, light/heat rays and any other wavelength of waves? The it-just-does argument comes to mind here actually hmm sorry. If the question is what Kandrona rays are then it's likely that it is some wavelength of light that is specific to Yeerks like how plants photosynthesise Yeerks kandrynthesise. Not a particularly specific question but it is my fault for picking it to try and answer!

how do they manage to avoid accidentally reproducing like amebas when they're pakced thousands into a pool?

This one I can't quite remember enough from the books to comment but presumably they're just like slugs or else they'd have some kind of uber baby boom. You can have a look at the wiki for slugs which at time of writing there are surprisingly more photos than are necessary (imo) and you might regret looking for it.

Thoughts? Other questions? Might have been a little pointless trying to explain how a fictional species can exist but in my defence this is a topic on Yeerk physiology and I like challenges when I'm a tad bored!

[Yarin]

that answer deserves a karma boost lol

[demos666]

that answer deserves a karma boost lol

i agree