Of Molecules and Ryka – A basic introduction to rykani biology
by Shzen Linh and Karu’yai “Karu” She’twe

Hi, there >} My name is Karu’yai She’twe, but my Cares’ons, Saikins, Yaxayones, Cutinages, Me’trians, Mawa, Kana and Xemihis and Dr. Linh call me “Karu”. Unless you are any of the above, though, and especially if you are a human, I would prefer it if you called me Karu’yai :#{

In my role of personal assistant to the one and only Dr. Linh, I’ve had the honor of working with one of the greatest of all human biologists for well over 28 human cycles now. Together, the two of us have truly revolutionized the human understanding of the ryka, and we will hopefully continue to contribute to this field of study for many cycles to come >}

Of course, our success was no accident! As you might have already guessed from my name, I, as a matter of fact, am actually a ryka myself, which makes me somewhat of a natural expert in this field of research >:}’ Dr. Linh, like the generally outstanding scientist that he is, was apparently aware of my inherent familiarity with today’s topic, and has therefore asked me to go over his entry ahead of its final publication. The highly symbolic nature of this task is not lost on me, and I would hereby like to thank Dr. Linh for allowing a member of the ryka to shape humanity’s perception and knowledge of our race :}’

While most of Dr. Linh’s writing was well up to the rykani scientific standard, I felt it necessary to comment on or slightly edit a few passages that might have otherwise sowed confusion amongst the human participants of this Exchange Program. To prevent any uncertainties about the respective authors of the following information, I’ve written all my edits like this, and all of my comments (like this). I hope you and Dr. Linh will find my contributions valuable >}’

Oh, and if you happen to encounter any passages between two weird text segments like “</hide…”, I will have to ask you to NOT read those parts of the entry. You see, apparently our internal information system had some sort of very rare, very weird glitch that has prevented us from hiding personal chat messages not meant for public viewing <:O We have already assembled a large team of human and rykani computer experts that is currently looking into the situation, but until the issue is fixed, I’ll have you know that everything written in the unhidden parts of this document is the PERSONAL PROPERTY of the ICRA. Those passages are protected by LAW and it is therefore ILLEGAL to view them unless you want to become a CRIMINAL and be put into HUMAN JAIL >:{ Thank you for your understanding :}

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@LS I’ve edited out a sizeable part of your introduction since it doesn’t really add anything to the topic□ Also, you should explain words like “PhD” before using them, just like Markóu said in his guidelines. If you keep throwing around abstruse phraseology like that, the other humans reading this will be just as confused as I was□□□
Karu, 21:20, 254^th, 93PA

@Karu PhD stands for “philosophiae doctor” or “Doctor of Philosophy”. It’s just an academic title given to those humans that contribute to our scientific effort in certain ways. Me having a PhD is also the reason why you and the others address me with the honorific “Doctor”. I’m surprised you didn’t know this, Karu. Regardless, since the first wave of humans partaking in the REP will be comprised solely of young aspiring Doctors, you won’t have to worry too much about my usage of niche phraseology. For now, I’ve reverted your edit.
LS, 9:23, 257^th, 93PA

@LS Oh, I see. Sorry…
Karu, 11:02, 259^th, 93PA

@LS Sorry, I broke the thingy at the bottom and now it doesn’t hide the text anymore□□□ Can you fix it for me, Shzen? Only if it’s not too complicated to do and doesn’t take too much of your time, of course□□ I told the others not to read the next few paragraphs, so it should be fine either way□ Sorry, again… □□□
Karu, 11:07, 259^th, 93PA
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Good day! My name is Shzen Linh, and as the head researcher of the Xenobiological Research Departments of the ICRA, I’ve been given the honor of writing up this short article and offering you a small glimpse into the topic of rykani biology. Of course, a subject as wide and complex as the entire field of rykani Xenobiology couldn’t possibly be fit wholly into the confines of this entry, which means that we, first and foremost, have to clarify the facets to be covered today.

As someone who, at one point or another, thought it a good idea to accumulate a total of three PhDs in fields adjacent to rykani biology (Xenobiology, Xenopsychology and Applied Xenoneuronal Engineering) and who has spent over 40 years teaching as a professor at the Kurt Heinrich Debus University on my snowy home planet of Provo, you might describe me as a lifelong scholar of today’s topic. Now, as I am tasked with writing an article for the first ever outreach program of our organization about this field of study that has consumed so much of my life, I feel an almost overwhelming temptation to present you with a complete history of our departments’ many research accomplishments.

However, given the highly complex nature of the study of xenobiological species from the other side of the galaxy, we have to limit the scope of this little foray to only cover the most fundamental aspects of our current understanding of the rykani xenobiological makeup. This will include a short history of rykani evolution, followed by an introduction into the topic of rykani biochemistry and finally a short overview of the most prominent phenotypical features of the modern ryka. While special attention has been paid to the understandability and digestibility of the article and its many subjects to follow, I must still ask you to excuse any short detours found in the writing below. Asking a human or ryka about his or her special interest can and will lead to excesses, after all.

But with all these necessary exclaimers now given, we can finally start our journey into the topic of the rykani biology with a look back in time into the origins of their genus.

Since our modern understanding of biology deems life to be a possible consequence of a few, extremely limited combinations of abiotic factors, it is worthwhile to start our examination of the rykani evolutionary path by looking at the environmental conditions of the planet on which their species first arose. However, since I have yet to acquire a PhD in the fields of Astrogeography and Rykani History, I will leave a proper examination of the rykani home world to another article in this series written by my colleague and friend Dr. Natille. Instead, we will focus the attention of this short planetary study solely on the aspects relevant to the evolutionary history of the ryka.

The ryka call their planet of origin “Tvi’ Rykaa”, a name that is often roughly translated into “Tent /  Nest / Home of the ryka”. This rather cool, rocky planet originally found itself orbiting a K1-V-type Star named “Katryk” (Katryk translates to “Sun” in human!) which, when compared to the Sun, the G2-V-type Star of our home planet Earth, stood out as a significantly smaller and cooler stellar object. Indeed, Katryk was so cold for most of its history, that Tvi’ Rykaa, as the fourth innermost planet of the system, initially fell just barely outside of the star’s liquid-water-zone. This unfortunate planetary positioning would have made the evolution of complex water-based life there almost impossible, had it not been for a rather fortunate circumstance.

You see, by sheer coincidence, the innermost satellite of Tvi’ Rykaa, a rocky moon by the name of Tre’va (Tre’va translates to “Moon”!), had formed in an unusually close orbit around its host planet. As a result of this lucky accident, Tvi’ Rykaa and Tre’va subjected each other to incredibly strong tidal forces that constantly exerted great stress on the surfaces of both objects. It was this stress, which, in turn, allowed the atmosphere of Tvi’ Rykaa to heat up thanks to constant tidal heating and the long-term accumulation of greenhouse gasses due to rampant volcanism. This same volcanism initially also threatened to cast Tvi’ Rykaa into a permanent ice age since the ash clouds and Sulphur-dioxide accumulating in its atmosphere further dropped temperatures. But as Tre’va slowly distanced itself from its parent object, and as the ash-darkened skies gave way to Katryk’s light, Tvi’ Rykaa’s climate stabilized at a temperature just high enough as to allow for the formation of liquid water seas along its equator.

Now, even with the fortunate rise in global temperatures across early Tvi’ Rykaa, these equatorial seas were significantly smaller and shallower when compared to the vast oceans that covered the majority of the surface of the human Earth. As a direct consequence, early life on Tvi’ Rykaa found itself constrained as very few regions of these equatorial seas were host to the limited sets of conditions that could allow abiogenetic processes to take place. This planet-wide lack of habitats suitable to the rise and evolution of early life forms inevitably meant that the first evolutionary processes on Tvi’ Rykaa took significantly longer to kick off than on Earth. While it is now commonly believed that the first life on Earth formed about 713 million years after the formation of our planet, the first traces of life on Tvi’ Rykaa could be dated no earlier than about 1.8 billion years after the planet’s formation.

Such a slow evolutionary start can and – according to numerous findings from planets around the galaxy – has already doomed many planets previously teeming with life into certain doom as the stellar evolution of the host star increases temperatures, eventually wiping out any lifeforms lacking the means to escape. Once again, though, the ryka were lucky in the composition of their home system.

With a K1-V-type star as its orbital host, and low temperatures to boot, Tvi’ Rykaa was granted a time window suitable for the evolution of life of around 12 billion years – a time frame longer than the entire stable main sequence phase of our Sun! Accordingly, despite slowdowns, life continued to evolve on Tvi’ Rykaa at a glacial pace. Just like on Earth, early life forms on Tvi’ Rykaa eventually enriched the seas and atmosphere with oxygen, almost wiping themselves out in the process, but eventually allowing aerobic life forms to arise, some of which soon left the equatorial seas behind and colonized the surface.

The climatic conditions of Tvi’ Rykaa continued to hamper the evolution of life even after its arrival on the surface, since most of the northern and southern regions were permanently covered in a thick blanket of snow. With only a small band of easily habitable space (stretched around Tvi’ Rykaa’s equator) available, early surface life initially evolved rather uniformly and soon stagnated from a lack of competition and evolutionary pressure. This state of affairs continued for a few million years until the entire equator was covered in a thick blanket of early plant life.

Interestingly enough, the rykani evolutionary history indicates that, once all habitable space was suddenly used up, evolutionary processes seemingly sped up rather quickly. Within a few hundred million years the uniform equatorial sludge had turned into a dense swamp almost bursting from its diverse range of different lifeforms, and the race for evolutionary domination of the equator regions was on. Without going into detail of this evolutionary race (since the history of Tvi’ Rykaa will be covered in another entry later on) as you might have guessed, the ryka ended up winning the competition thanks to a combination of evolved social behavior, their ability to coordinate with other members of their species using linguistics, a pair of hands that allowed for the precise manipulation of their environment, and a strong sense of curiosity.

All right, with all these details of their evolutionary history in mind, we can now take a look at the modern ryka and see how the environmental conditions of Tvi’ Rykaa shaped the species we see today. Let us start this examination with a quick look into their biochemical makeup.

To begin with, it is worth noting just how similar the biochemistries of rykani and humans are on a surface level. Let me just name a few examples of seemingly impressive degrees of convergent evolution: Both the ryka and us are multicellular beings, we both use water as our main solvent, both of our chemistries are dominated by carbon-molecules (Although rykani biochemistry also loves incorporating random boron and aluminium bonds into our proteins for some reason :>), we both make ample use of phosphates, we both use amino acids to inherit genetic information and to create different proteins, we both possess soft tissues (skin, muscles, etc.) and hard structural elements (bones), we both possess discrete organs, we both possess a central nervous system and we both transport chemical compounds across our body through fluid channels (blood vessels).

I could name many, many more features that show almost uncanny degrees of convergence from two species that supposedly grew up on very different planets separated by tens of thousands of lightyears. No wonder, then, that for the first fifty odd years after making contact with the ryka, most human xenobiologist were touting their species as ultimate prove of panspermia or intelligent design. That was, until we first got to sequence the rykani genome. For however many phenotypical similarities the ryka share with us on the outside, the story is quite different on the inside.

The proteinogenic amino acids of the ryka are a great starting point to begin our examination of the many differences that separate their biochemical makeup from that of us humans. Let us begin by looking at their varieties and inheritance. While our human genetic sequence encodes information for 20 + 2 proteinogenic amino acids, the more complex genetics of the ryka encode a total of 28 + 3 types of amino acids, 5 of which are actually shared between both of our species.

To store and inherit the information of these proteinogenic amino acids, the ryka use three different nucleobase pairs, made up of six different nucleobases, in their genetic sequence. These are:

• Xanthine (3,7-dihydropurine-2,6-dione) and Nerekoline (7-methyl-6-amino-5-nitroso-2(1H)-pyridinone)
• Zebularine (1-(β-D-Ribofuranosyl)pyrimidin-2(1H)-one) and Quinonuazoline (5-nitro-1,3-diazanaphthalene)
• Teluparevaline (2-(1H-pyrrol-2-yl)pyrimidin-4-amine) and Rykanine (4-amino-5-hydroxypyrimidine)

These base pairs form nucleotides that are strung together in a rather irregular double-helix formation, again, quite similar to us humans, although instead of ribose / deoxyribose the ryka use cyclohexenyl as their sugar backbone. Finally, the resulting nucleotides are split into fourteen different circular Quasi-Chromosome pairs for a total of twenty-six autosomes and two gonosomes.

While we are on the topic of rykani genetics, we should also stop to take note of the rather special regenerative capabilities of rykani genomes. Experiments subjecting their Quasi-Chromosomes to prolonged radiation exposure and strong acidic environments have managed to verify rykani claims of extreme genetic resilience. To understand how these resistances came to be, we once again have to turn our attention to the rykani planet of origin.

Owing to the acidic atmosphere and seas of early Tvi’ Rykaa, a result of the previously discussed increased levels of volcanism, the first organisms had to be very acidophilic by nature. Despite the environment neutralizing over time, life on Tvi’ Rykaa has remained very acidic to this day, a fact that is best reflected in the diet of the modern ryka. Yes, there is, in fact, a good reason as to why the ICRA forbids humans from coming into contact not just with rykani bodily fluids but also their food. From my personal experience of once having had a ryka accidentally pour her drink on me, I can attest that prolonged contact with their dietary products, while non-lethal in most cases, is still rather unpleasant and almost guaranteed to leave marks.

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@LS I CAN’T BELIEVE YOU BROUGHT THIS UP□□□□□□□□□ I HAVE APOLOGIZED SO MANY TIMES FOR DOING THAT, AND YOU STILL HOLD A GRUDGE□□□□□□□□□□□□□□□□□□ THAT IS THE EXACT REASON WHY I DIDN’T TELL YOU ABOUT MY SURPRISE INSPECTION OF YOUR WORK□□□□ YOU HAVE BEEN CAUGHT IN THE ACT□□□□□□□□□ I SHOULD JUST DELETE THIS ARTICLE RIGHT NOW□□□
Karu, 21:44, 254^th, 93PA

@Karu Karu, you know very well that I didn’t write this short passage up because I have some sort of grudge against you. If I did, I would have mentioned you by name, right? My intention was to simply give the reader a more personal warning about what could happen if he or she were to come into contact with one of your beverages. For the sake of preventing needless injury, I’ve reverted your edit. We will talk about your feelings towards me mentioning this story in my office later today.
LS, 9:38, 257^th, 93PA

@LS Guilt tripping me like that was not the right thing to do, even if I was wrong… □□□□
Karu, 11:17, 259^th, 93PA
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In addition to their acidophilic nature, the ryka, as mentioned above, also show a great deal of radiation resistance. The manifestation of this trait in seemingly all lifeforms stemming from Tvi’ Rykaa is deemed by many to be proof enough of the dangerous radiation levels that their early ancestors in the equatorial seas had to endure. Some human pop culture from times shortly after the Treaty of Equals even went so far as to satirically portray Tvi’ Rykaa as a nuclear wasteland, littered with highly radioactive compounds, and for some humans, this view persists. While the abundance of undecayed radioactive materials on early Tvi’ Rykaa’s surface may have been a contributor to the initial evolution of the rykani radiation resistance, it is now thought that the planet’s weak magnetic field (Compared to human earth) was by far the more substantial factor. Given Katryk’s stellar classification and Tvi’ Rykaa’s closer proximity to its parent star, we can confidently assume that early organisms within the equatorial seas were subject to a lot more UV and X-Ray radiation exposure than any life during similar timeframes on Earth.

With this abundance of hazards towards the structural stability of larger molecules, evolution on Tvi’ Rykaa favored a great number of different stabilizing or restorative properties, from regenerative proteins to structural changes, some of which the ryka eventually inherited from their ancestors. This same resistance towards common sources of genetic damage also allowed the ryka to enjoy longer lifetimes than those natural to us humans, even well before they had achieved their current status of biological immortality. While sources and reports from the ryka differ wildly as to the exact lifespans of their early ancestors, we can confidently say that lives of 80 to 140 S-Years were considered normal even during the earliest parts of their recorded history. (But only in the less dangerous regions of Tvi’ Rykaa!)

All right, this marks the end of our lesson on rykani biochemistry. Now, as a last topic for today, let’s zoom out to explore all the many phenotypical differences that separate the ryka from us humans.

Of course, the most immediately noticeable dissimilarity between humans and your average ryka can be found directly on the surface level. Where we humans are covered by a smooth, leathery skin and some variable spots of hair, the ryka carry around an impressively fluffy plumage similar in appearance and touch to the down feathers found on some avian species from Earth. More often than not, we simply refer to this plumage as feathers, although given the numerous structural differences between earth feathers and rykani feathers, we scientist felt it necessary to give them another name. Some time ago, my department came up with the term “Plocculli”, a neologism combining the Latin words for “soft’ and “feathers”. Quite fitting, don’t you think? (We rykani call our feathers “Wekepha”, but some of my shatilmembers also use the word “Wek’”. I don’t know if that abbreviation is common, though <:<)

The rykani Plocculli come in a vast variety of colors, lengths and shapes. Aside from their natural purpose of temperature management and heat retention, nowadays, the Plocculli also play a role in rykani society similar in concept to human clothes. The ryka place a lot of value into the presentation of their Plocculli, and the grooming, cleaning and styling of their plumage sometimes forms an important part of their daily routine.

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@LS What?! But that’s just outright wrong□□□□□ I don’t care about my feathers, and neither does any ryka I know. Flip, I can’t even remember the last time I cleaned them□□□□ That’s what Autonodrones are for□□□
Karu, 21:59, 254^th, 93PA

@Karu From my many dealings with other ryka over the years, I actually have to disagree with you here, Karu. There are quite a lot of your kind out there that actually groom and style their Plocculli extensively. However, I do fully understand your primary concern, and the fact that the importance of Plocculli presentation differs greatly between rykani planetary cultures probably needs to be mentioned within this article ahead of final publication. For now, I’ve reverted your deletion of the passage, but we can discuss this topic in more detail later today.
LS, 9:46, 257^th, 93PA
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Some ryka even go as far as coloring or painting their Plocculli, changing their appearance through digital means or styling them in a variety of ways. Our departments have also learned of several rumors that some ryka even cut their Plocculli, but given the fact that almost all of them contain blood vessels and pain receptors, we have to express our doubt over these reports.

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@LS WHAT?! NO! NO! NO! NO ONE DOES THAT □□□□□□□ DO YOU EVEN KNOW HOW MUCH IT HURTS WHEN YOU BREAK OFF ONE OF YOUR FEATHERS□□□□□□□□□
Karu, 22:03, 254^th, 93PA

@Karu See above.
LS, 9:48, 257^th, 93PA
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Let’s now start going through the major biological features of the ryka from top to bottom, starting with their ears. Similar to the ears of many Earth predators, their rykani analogs offer a wide range of motion that allows them to hone in on directional noises, and thanks to the large size of their cups, rykani ears also sport a lower absolute hearing threshold than their human counterparts. Today, the ryka exploit their outstanding hearing capabilities in a number of biomechanical ways, like using their ears as receptors for environmental scanner data or exploring far off stellar objects through their so called astronomical “listening posts”. Additionally, as mentioned in previous entries to this series, the rykani use the large range of movement of their ears to form subtle cues within their social conduct.

Moving downwards, we encounter the rykani skull and, more importantly, the brain contained within. The specifics of rykani neurology form another topic that falls outside of the scope of this article, and you’ll have to wait for the chapter on rykani neural interfacing technology to learn more about this subject, but to quickly summarize the most important points: Rykani neurology is, principally, very similar to that of humans. We both use electric action potentials to convey information, and both our evolutionary paths have chosen the skull as the place of central residence. Although, unlike our human brain, the rykani brain also stretches down into the upper neck through several thick strands. These strands then conglomerate around the rykani spine and either run through or alongside it into the torso, lower body and tail.

Below and in front of the brain we find the two strikingly large eyes of the ryka. Similar to the rykani brain, their eyes also show a remarkable degree of convergent evolution with us humans. At least in appearance, that is. In actuality, despite any and all visual similarities, the inner workings of the rykani eyes are far removed from those of ours. Owing to Tvi’ Rykaa’s dimmer, rather distant host star, the ryka are naturally more adapted to the perception of lower energy light waves and, accordingly, show great visual capability in low-light conditions. Thanks to their possession of five primary types of photoreceptive cells, the rykani visual spectrum can reach as low as 1200 S-nm and as high as 480 S-nm in some individuals.

In addition to those primary cells, the rykani eye also features two rather curious, underdeveloped secondary receptive cell types. The first of these types can sense photons in the range of 430 to 375 S-nm, allowing a ryka to vaguely sense UV emitting and reflecting objects, but in no great detail. The second underdeveloped cell type is an even more strange case. It detects photons in the 16 to 2 S-nm spectrum, around the upper range of Röntgen Radiation, but their receptive signals actually bypass the rykani visual cortex and instead get processed by the part of their brain responsible for the rykani sense of taste. This weird evolutionary anomaly is why many ryka claim to be able to “taste” radiation when exposed to strong X-Ray emitters. (If you’re wondering: It tastes kinda salty, slightly metallic, and very tingly. Kind of like eating an unripe, undercooked Wtewhu mushroom.)

Many theories have been proposed that attempt to explain the evolution of such a highly specific but seemingly useless sub-organ, most of which center around the previously discussed increased output of UV and X-Ray radiation from Katryk during the first three billion years after Tvi’ Rykaa’s formation. However, despite any and all efforts, a plausible evolutionary benefit that would reasonably cause the spread of such a mutation has yet to be determined.

Below and between the eyes, we find the rykani “snout”, a small outcropping of bone and tissue in the middle of the rykani facial structure. Similar to us humans, the ryka use this extruded region of their face as a location from which to smell their surroundings, although despite popular belief, the ryka don’t actually possess a human-like nose below their Plocculli cover. Instead, they rely on passive Smelling-Pores. These tiny, concave dents can “smell” particles that enter them, but since they aren’t connected to any respiratory organ, they are prone to clogging up. This is the reason as to why you regularly see a ryka rub his or her snout, especially when asked to smell something.

Finally, as the last item of note within the rykani facial structure, we have the rykani mouth. The mouth forms another major point of co-evolution between the ryka and us humans, with both of us using our primary face holes for food consumption and vocalization. Still, the rykani mouth has some distinct differences to their human counterpart that bare mentioning. First, they don’t only possess one, but three separate tongues. The main tongue, by far the largest and situated along the center of the mouth, is flanked by two smaller, split-off muscles that help the ryka with their food consumption and vocalization of different clicking and whistling noises. You should also be aware that none of those three tongues host any taste buds like those found on a human tongue. Instead, their rykani equivalents are simply situated along their inner cheeks.

In front of the tongues, we also find the 18 rykani teeth, of which 10 populate the upper jaw while the other 8 sit below. Comparing them to their more numerous human analogs, the rykani teeth are both more brittle and prone to breaking off, but also more temporary in their nature. Similar to some animal species from Earth, the rykani teeth are in a constant state of regrowth, with the visible portions usually being fully replaced every 400 Standard Days. As a result, the rykani jaw is populated by a rather ununiform landscape of teeth, with only their two large fangs of the upper jaw standing out as major landmarks.

Below the rykani chin, we find a rather uninteresting throat situated above our next area of focus: The rykani torso. Despite me having debated numerous times in favor of a tour of every single rykani organ within this article, luckily for you but unfortunately for me, my superiors have decided against such an extensive coverage. As a result, we’ll have to focus on only the most important rykani organs in the following section. However, if you are interested in a more in-depth study of all the rykani organs, you can ask the lead researcher of your course for additional material on the subject.

Let’s start off our tour of the rykani torso with their respiratory system. As mentioned above, the ryka use a (very acidic) solution composed of many different cell types to both supply their body with nutrients and to allow for the gas exchange that many of their internal functions rely on. To supply their acidic blood with oxygen, the ryka possess are large number of muscle-actuated “Air Sacks” similar in concept to our human lungs. The average rykani possesses between 11 and 14 of such little Air Sacks, spread throughout the upper region of the rykani torso.

Out of these 11 to 14 air sacks, between 8 and 10 of them supply the primary heart with oxygen, while the rest of them supply the rykani secondary heart. Yes, you heard that right, the ryka actually possess two different hearts. The large primary heart is responsible for supplying the lower body and all appendages, while the smaller, more protected secondary heart supplies most rykani organs, including itself, their brain and parts of their torso. If you were to put your head on top of a rykani chest, an exercise we intend to include in our Exchange program, you could clearly hear the independent beats of both hearts.

The remaining rykani organs serve the functions you would expect: A two-parted stomach and a chain of intestines allow for the digestion of and nutrient extraction from food and drink. The spherical Filtering Clods clean the rykani blood, and the rykani bladder deals with the excretion of waste products and contaminants. As stated before, we sadly can’t go further into detail on these organs within this entry.

Sitting to the left and right of the rykani torso sit their two arms. As another impressive display of convergent-evolution, the rykani arms show great muscular similarity to their human counterparts, although their bone structure shows some stark differences. Both their upper and lower arms are actually split into three distinct bones around and through which the rykani musculature is woven. Despite many resulting theoretical differences in muscular movement ranges and actuations, the practical range of motion of a rykani arm doesn’t differ much from us humans.

Similar structural redundancies can also be found when looking at the rykani hands. While initially also seeming rather close in design to our human hands, the rykani analog’s most striking feature is its lack of a fifth finger. Interestingly enough, the ryka still possess degenerated bone structures indicating that their ancestors not only possessed a fifth, but also a sixth finger. Additionally, some ryka possess extendible claws at the tops of their fingers, but given the recessive nature of this trait, sadly, very few of the modern ryka still have them.

Going back to the torso and looking below, we find the rykani groin, and on the front, there’s not much going on. After turning our ryka around, however, we are immediately met by a large, fluffy tail that acts as an extension to the rykani spine. The rykani tail serves a wide range of functions in their everyday life, most important of which is the stabilization it offers to the somewhat frontally offset posture of the ryka. But aside from its primary use case, it also allows for the rather precise manipulation of objects, offers the ryka support whenever they balance on or dangle themselves off of a branch or pipe, and, of course, also serves a variety of social functions, similar to the rykani ears.

Looking at the underside of the rykani tail, we find the rykani genitals and their Secretion Hole. Unlike us humans, the ryka both clean their blood and rid themselves of nutrient waste by excreting a single, viscous liquid through a single opening. Above this secretion hole sits the rather small and shallow rykani genital slit, which is quite similar in design between both Kaeh and Ko.

Since the topic of rykani reproduction will be further expanded on later on in this series, it WON’T BE DISCUSSED HERE AT ALL X(‘

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@LS EWWWW! ARE YOU SERIOUS □□□□□□ Why in the FLIP would you bring this topic up here?! Markóu told you not to cover any organ functions in detail!  I know because I’ve accidentally read your message history with him □□□ I have deleted EVERYTHING related to this… stuff, and now I’m very angry with you □□□□□□
Karu, 22:19, 254^th, 93PA

@Karu Karu, I’m sorry for having made you upset with my writing, but I’d like for you to listen to me for just a moment. You know very well that I, thanks to my many years of interacting with different ryka, am more than aware of the culturally inherited discomfort your species feels when discussing matters related to sexual reproduction. However, as scientists tasked with educating the masses on all matters related to the ryka, both of us have to step out of our comfort zones in the pursuit of scientific objectivity. Human participants will have to learn about the rykani reproductive process at one point or another during the Exchange Program, and the short paragraph above was simply meant to give the reader a short primer ahead of the article that will cover the topic in great detail regardless of your objections. For now, I have re-added a shorter and more concise version of the original paragraph. We can go over the details of my writing later in my office, and I’ll be sure to address any further criticism you may have.
LS, 9:59, 257^th, 93PA

@LS NO! NO! NO! I’M NOT COMPROMISING ON THIS□□□□
Karu, 11:28, 259^th, 93PA
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Moving down for the final time, we arrive at the rykani legs and feet. For how similar the rykani arms and hands are to their human counterparts, their lower appendages differ in quite the number of major ways. Of course, the most obvious of these differences is the rykani digitigrade posture, which, as discussed previously, needs to be balanced through their tail. Compared to plantigrades such as us humans, the ryka could be considered as being in a constant state of tip-toeing on their phalanges, while their bones that form the analogs to our human mid- and hindfoot extend upwards without making contact to the ground.

A detail worth remembering is that the rykani posture also contains one of the very few visual expressions of their sexual dimorphism. If you compare the legs of a Kaeh and a Ko side by side, you will notice that the Keah possesses shins that are generally longer than the feet below as opposed to the shorter shins and longer feet of the Ko. The exact reason for this strange dimorphism is currently unknown to both us and the ryka, but it is often thought that earlier ancestors of the modern ryka simply laid eggs bigger in proportion to their bodies, necessitating changes in the hip and leg structures of early Kaeh ancestors similar to those of human females. As the body sizes of rykani ancestors grew more in comparison to the scale of their eggs, these altered structures would have ultimately lost their purpose while, quite likely, presenting numerous disadvantages over the narrower leg and hip structures of the Ko. Evolutionary pressures would then have favored Kaeh with leg and hip structures more similar to the Ko, eventually leaving us with the discrepancy in shin and feet sizes as the only remnant of this evolutionary roundabout. Sadly, we possibly won’t ever have definitive fossil proof of this hypothesis, given the fact that very little of Tvi’ Rykaa’s original surface remains below the hundreds of S-Km of rykani structures now built atop of it.

Moving on to the rykani foot, we can immediately note their possession of only four toes. Their arrangement differs greatly from our human feet, as the two big toes to the front contribute the largest amount of surface for the ryka to walk on, while the smaller, inner toe is used mostly for stabilization. The fourth, rear facing toe makes the most interesting case, as it can bend downwards enough to come into contact with the two primary toes, allowing the ryka to dangle themselves off of pipes and branches by their feet, similar to some avian species from Earth. (Not for long, though. Dangling by your feet like that is just as fun as it is exhausting >:>)

At the tip of the rykani toes, we also find the final difference to us humans that is worth noting: The rykani talons. Made out of hardened proteins and other carbon compounds, the ryka talons offer great structural strength, useful for slashing enemies in a pinch. (While we ryka prefer fighting with rifles and modernized, manufactured melee-weapons, some of us still treat our talons as a weapon of last resort. As a disclaimer: I, personally, wouldn’t recommend going up with your talons against guns capable of relativistic acceleration <:<)

With that, I believe we have covered all important aspects of the rykani body. As said above, this was only meant to be the most introductory introduction to the topic at hand, and I hope to have given you just that. Of course, as a last reminder, it is perhaps worth mentioning that any and all facts detailed within this guide are very likely to change as our understanding of the ryka grows and evolves. Just like most other subjects studied by the ICRA, the field of rykani biochemistry continues to be an area of ongoing research, with the many, large gaps in our knowledge only slowly being filled. If you are interested in the continued study of this topic beyond the scope of this Exchange Program, you may, at any time, ask your course’s lead scientist for further educational materials. Either way, I highly encourage you to revise the topics covered within this entry multiple times throughout the course of the theoretical part of your Exchange, as it forms a major part of the final exam. This guidebook also offers you several practice exams covering all the discussed intricacies of the rykani body, with a major focus put on the consequential effects on human-rykani communication. I most highly recommend you go through all of these practice exercises ahead of your final exam.

And once you feel confident enough in the matter of rykani biology, you may move on to the next entry in this series, written by my colleague Dr. Ensio, which will try to make sense of the confusing world of rykani measurements and mathematics. I wish you all the best on the remainder of your journey with the ICRA and suggest you keep your ears down.

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@LS Hey there, Shzen□□□. Sorry for not telling you beforehand, but I found some minor mistakes when reading your article about the basics of rykani biology□ Nothing too serious, which is why I didn’t want to bother you with this during our daily meeting, but just about bad enough that I thought I’d help you out by making a few edits myself □□□ I’ve marked all of my edits by using the weird tilty thingy, so you can look those passages over one more time if you want to □, but after reading the whole thing through once more, I feel that everything is totally correct and up to date with our modern understanding of rykani biology now. You can thank me later by paying for my drink □□□□□□
Karu, 22:42, 254^th, 93PA

@Karu Thank you for your astute comments, Karu. While I warmly welcome any and all insights that a member of the ryka can provide to a discussion of their species’ own biological foundations, I did feel the need to make a few edits to your comments. Of course, all of these edits were made carefully in order to retain the original meaning of your remarks, but since this entry is simply intended to be a short introduction to the topic of rykani biology, I felt the need to tighten up some of your elaborations. Also, you might not have been aware, but our internal database system doesn’t currently support saving any characters from the Extended Rykani Emoticon Typeset. You should have received a pop-up informing you about that when saving. After you selected “Save Anyway”, all your emotes were replaced by a □, which slightly messed up the formatting of my entry. I would have preferred if you had come to my office and allowed us to make the required changes to my entry together instead of you taking the sole initiative in this. I know that your intentions were well-meaning, but in the future, I do ask for you to tell me about any shortcomings in my writing before breaking into my private file system, changing my passwords, locking me out of my office and invalidating my DIGI-ID in the process.
LS, 10:32, 257^th, 93PA

@LS Hey, Shzen! I know you told me not to edit your stuff again without prior notice, but this one was just too much! I mean, I get that you need to trivialize things so that other humans understand this stuff, but I don’t think that gives you the permission to just straight up lie! Even if we ignore the fact that I AM a ryka, I’ve been researching rykani biology for well over 130 cycles now. I don’t want to straight up claim that I am better at this stuff than you are, so instead, I’ll just ask you to put some faith into your research partner of 28 human cycles. The last-minute edits I made were minimal but strictly necessary, and everything I wrote was written in the interest of furthering the collective human understanding of my species. If you take any issue with anything I wrote, we can discuss this AFTER you upload this entry. If you just edit my edits again without telling me, I have no reservations about running back into Markóu’s office and ratting you out again.
Karu, 11:43, 259^th, 93PA
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