Yeerk Psychology and Science (Chock full o' spoilers)

[Bealocwealm]

So on reflection, I'm beginning to think that a lot of the issues the Yeerks have happen when a Yeerk associates too fully with their host.

Taylor, obviously, is a prime example, but Visser One is an example as well. Visser One associated too fully with her host body, and the human concepts of love and parenthood (Yeerks, remember, should have no concept of parenthood outside their host, as they are destroyed by their mating process) changed her in at least one important aspect -- she bonded permanently with her human children.

But, hang on -- Yeerks should have no idea of mates, unless they have taken on traits of a host. Yet there was that one Controller who helped the Animorphs as vengeance against Visser Three because Visser Three killed his 'mate'. Is this just odd because we don't know a lot about yeerk pool society? Do Yeerks form an equivalent to shorm, something unrelated to actual mating? Or did that Controller bond too fully with his host and become involved with the host's concept of relationships and love?

And then there's the fact that I've been referring to these Yeerks as "he" and "she" -- where Yeerks, in their natural form, have either no gender or three genders. (As it takes three Yeerks to breed.) Indeed Yeerks will refer to eachother based on the gender of respective host bodies, without exception that I can think of off the top of my head, and in private, all-Yeerk areas too.

Many Yeerks seem to even have a gender preference; Visser One prefers female hosts, taking at least three female human hosts over her life on Earth. I believe she is referred to as female before taking a human host, so we might assume she had a female Hork-Bajir host as well. Do Yeerks consider gender to be another type of sensory information like colour? Is this why they develop a preference? Or is this all because of bonding too closely with the host again?

My personal theory is that Yeerks have no concept of gender before they enter a host, but that the gender of the very FIRST host they enter imprints upon their self-concept -- that is, that Yeerks are more affected than we suspect by the very act of controlling, and that it changes their... neural pathways, or brains, or whatever. The Yeerk would be imprinted as a gendered being, and would come back to the pool different -- not actually possessing a gender, but possessing a gender identity.

 This could actually be used as an explanation for Yeerk intelligence and sentience. In reality, it would be highly unlikely that they could evolve such things in stagnant pools with no natural predators, no prey, and no outside pressures (for instance having to communicate with eachother and navigate complex problems to get to Kandrona rays). We will assume that Yeerks have the ability to interface with brains as a result of their ability to interface with *eachother* to communicate in-pool, however primitively. Here's another "This Is My Theory" Bit.

Say, theoretically, that there was at one time on the Yeerk planet at which a primitive but intelligent being roamed the surface above the pools (I don't know if Gedds count, let me know if they do); the volatile nature of Yeerk Planet weather alone does give them some evolutionary incentive to need intelligence. Possessing curiosity, it scooped up a Yeerk from the pool and, seeing movement, put the Yeerk to its ear to see if it made noises also. (Sounds silly, but I could see a toddler or something doing that.) The Yeerk, sensing neural activity, travelled up the ear canal. Eventually, the Yeerk discovered it could control this creature, but it also discovered real, however primitive, intelligence. This being the first host, the Yeerk was imprinted somewhat upon it; not only in concept of gender if applicable, but its neural pathways restructured severely. Later it left the host to return to its pool, and eventually bred. Either its DNA was somehow restructured (unlikely) or it still had the DNA of that first host on it -- either way, the resulting Yeerks were left *aware* that they could control other creatures, and more intelligent for the essentially mutant DNA. This process could happen with a great number of Yeerks. The resulting Yeerks would be at an evolutionary advantage, as they could leave their pool and travel long distances to another if it threatened to dry up.

I dunno, it's a bit silly, but it's an idea I've had. (Another, probably more reasonable idea suggests that Yeerks at one time had far greater evolutionary pressures, and that 'sitting around in stagnant pools their whole lives' is a relatively recent development -- just as 'fast food joints and no real predators' is a recent development in human evolution.)

[Terenia]

Oh, I could write a novel about the idea of Yeerk love and Yeerks becoming too attached to their hosts. But I won't...instead I'll comment on the part of your post I don't readily agree with.

Say, theoretically, that there was at one time on the Yeerk planet at which a primitive but intelligent being roamed the surface above the pools (I don't know if Gedds count, let me know if they do); the volatile nature of Yeerk Planet weather alone does give them some evolutionary incentive to need intelligence. Possessing curiosity, it scooped up a Yeerk from the pool and, seeing movement, put the Yeerk to its ear to see if it made noises also. (Sounds silly, but I could see a toddler or something doing that.) The Yeerk, sensing neural activity, travelled up the ear canal. Eventually, the Yeerk discovered it could control this creature, but it also discovered real, however primitive, intelligence. This being the first host, the Yeerk was imprinted somewhat upon it; not only in concept of gender if applicable, but its neural pathways restructured severely. Later it left the host to return to its pool, and eventually bred. Either its DNA was somehow restructured (unlikely) or it still had the DNA of that first host on it -- either way, the resulting Yeerks were left *aware* that they could control other creatures, and more intelligent for the essentially mutant DNA. This process could happen with a great number of Yeerks. The resulting Yeerks would be at an evolutionary advantage, as they could leave their pool and travel long distances to another if it threatened to dry up.

This bit sounds a little like the, "giraffes stretch their necks real long to make their kids have longer necks" theory. I think it's more logical that the Yeeks did have natural predators within the pools, at least at some point in their evolution, and the most advantageous way to avoid them was to either infest the predator itself, or some other 'aquatic' species. I think this is where they developed most of their abilities, but it was expanded upon when some unfortunate Gedd or something happened to fall into a pool and was infested (or perhaps a curious Gedd put one up to his ear, as you suggested).

As for their intelligence, the existence of natural predators would encourage that on at least a rudimentary level. Natural selection would probably tend to prefer the smarter Yeerks that were better at hiding from their predators, especially those innovative enough to get out of the pool somehow.

[NateSean]

But, hang on -- Yeerks should have no idea of mates, unless they have taken on traits of a host. Yet there was that one Controller who helped the Animorphs as vengeance against Visser Three because Visser Three killed his 'mate'. Is this just odd because we don't know a lot about yeerk pool society? Do Yeerks form an equivalent to shorm, something unrelated to actual mating? Or did that Controller bond too fully with his host and become involved with the host's concept of relationships and love?

Without knowing about Yeerk society before the Andalites came along, it's hard to guess. But it's not so far fetched that Yeerks do genuinely care for each other's company. They're comfortable when they are in the pool with other Yeerks. Not all of them relish the idea of taking a host and leaving that nice, cool, crowded pool.

We know that Twins have a unique bond and that Yeerk society doesn't seem too intent on seperating them until one proves itself more valuable to the goals of the Empire. Before becoming a sub-visser, Esplin joked with his twin while he was guarding the Yeerk Pool. Two yeerks just goofing off on the job, or was Esplin 2 actually assigned to guard the pool as well?

At the same time, there's not a lot of emphasis on self. Like any other animal in creation, a Yeerk will certainly take any opportunity to save it's own life, but when all else fails they seem to accept death more readily than most. Of course the only instance we see of a Yeerk dying is through Jake's eyes, when Temrash basically says that it's useless to fight when there is no hope. Temrash's mindset is that if he dies, there will be plenty of Yeerks to take over.

Is this the mindset of the entire species when it nears death, or is it just one Yeerk's attitude when all of the cards are set? Temrash did put up a good fight but he accepted his death in the end. Even Visser One (Formerly 3) accepted the inevitable when he was surrounded by Animorphs, the Blade Ship was about to fire on the Pool Ship and an Andalite fleet was on it's way to drop rainbows and puppies on the Earth.

[Myitt]

This bit sounds a little like the, "giraffes stretch their necks real long to make their kids have longer necks" theory

*shakes fist* Lamarck!

I, too, could write a novel about this stuff...sigh.

To me, it seems more like maybe Gedds and other hosts swam in or drank Yeerk pool water, and the first Yeerk with the evolutionary adaptation to infest decided to use the host for protection from creatures like the vanarx. Perhaps over time this protection became a literal attachment to the brain.

Or...we could just say Crayak did it!

I love Yeerks and their gender-bending abilities!

[RYTX]

But, hang on -- Yeerks should have no idea of mates, unless they have taken on traits of a host.

I don't think that's true. I understand why you might think it's true, cause until just now so did I, but assuming that Yeerks vary in reproductive quality, there's no reason to not assume that the Yeerks make careful evaluations of who they breed with. Even if it's fatal to all parties, they have 2 mates each, and only once, but that doesn't mean there isn't still some assortative mating when they go to do it. Right there is a need to be able to communicate: which they have, via squeaking. Overall, I agree with your point, but I wanted to make that plain too

Still, Yeerk identity seems horribly warped throughout. You nailed gender, but lets also keep in mind that throughout many Yeerks seem to respond to their host names, even in private Yeerk affairs. After book 2 Chapman was always called Chapman, even by Vissers. Is that just consistent covering, or do they forget? In fact Vissers are the most obvious exceptions, yet they're mostly addressed by rank.

Yeerks do seem susceptible to being caught up in host activity and enjoyment as well. Oatmeal, cookies, drugs, whatever, Yeerks get host happy.
If only to keep it short, I'd keep it primarily psychological over genetics: The Yeerks spend all but a few hours at a time as their host. Completely and intimately ingrained in that life. The Animorphs, who are in different forms of life for only a few hours at a time, still always have to be on guard. Instincts are hardest at first but never go away. If you're not actively doing something to keep you apart from the role you're playing, maybe it really is just harder not to give in.
Which on my early thing about names: that applies mostly to humans, still undercover on Earth. In alt. futures, and times when Yeerks have total control, we see Yeerk names more, and I think that's because they no longer are playing the part, and are less likely to be swept up in it.

[Noelle]

I'm not quite sure how to put what I think coherently.

There is a difference between inherent IQ and potential intelligence.  In a Yeerk's natural environment, there is no need to learn about love and ongoing mates.  There's no real need to form bonds, deep attachment, and a separate identity.  That doesn't mean they don't have the potential to.  If you keep a child locked in a dark room for their whole life, they are going to seem completely devoid of intelligence and social ability, however, if you taught that child they would develop it because they have the potential.

I always kind of thought of Yeerks like blank slates...they have an overwhelming potential for intelligence, but they aren't just born knowing what they can't know.  It's already shown in the books their intelligence and understanding develops as they gain more hosts.  I don't think their mental capacity increases, they just learn about what they didn't know.

One thing I noticed is that Yeerks that had a whole bunch of hosts for short amounts of time (like Visser 3) don't associate with their hosts as much.  They view their hosts as tools and nothing more.  However, Yeerks born in the midst of the Yeerk invasion and who have only had one, consistent host for a long period of time are more likely to bond with their host and adopt their ideals because that host is all they know.  They didn't have the varied different world views and intelligence levels of different hosts.  Visser One had different hosts, but the host type she/he/it had the longest was a human host, so she developed human attachments.  I would say there is no way a Yeerk can't be changed emotionally/mentally by their host.  Visser 3 on the other hand, spent most of his time in a Gedd then a Hork'Bajir, who have limited mental capacities themselves.  Then he got an Andalite host, and honestly while he views Alloran's body as a tool to go towards greatness, you can see A LOT of Andalite psychology in him, especially Alloran's psychology, a slash-and-burn mentality that Alloran developed over the course of the Andalite war.

So I think that association/integration with the host is just an obstacle that naturally occurs as a part of who they are.  Keep in mind, technically Yeerks aren't parasites, they are dependent on their hosts for anything except life enrichment, so that in itself is already an emotional bond vs. a purely necessary bond.