Author's Note: Chapter two: the Senses. Yes, I lied last chapter about this being the life cycle installment. Why? Because ri2 pointed out that I didn't cover antennae in the anatomy chapter. So I wrote a new chapter to rectify the error.

---

Mommaleasey- Thank you! Also, I very much appreciate the watch.

---

ri2- (Headdesk) I forgot the antennae. How could I forget the antennae?! For pointing out this error and consequently making me write this chapter, I suppose this installment is dedicated to you.

---

LoneHowler- Thanks for the review and the watch. Hope this chapter doesn't disappoint!

---

avatarjk137- Glad you like it! Thanks for the watch.

--- Senses

Irkens have a wide range of senses incorporated in to their physical bodies as well as senses that their PAK can simulate. The first sense is sight, which Irkens artificially enhance with optical implants; ranging from chips in their PAK that improve visual image quality and clarity to complete cybernetic optical implants. Irkens eyes are forward facing but protrude from the eye sockets, giving them a both a wider range of vision than humans and a larger percentage of visual overlap (both eyes seeing the same image). The Irken range of vision is around 260 degrees, with a total of 210 degrees of vision for each eye. In order to calculate total vision, it should be noted, the degree of visual overlap, 120 degrees for Irkens, must be subtracted from the degree of vision in one eye and the resulting number added to the degree of vision unique to each eye, 70 in this case, in order to find total vision range. Humans, in comparison, have a total visual range of 180 degrees with a 90 degree overlap, giving each eye a unique visual range of 45 degrees.

Interestingly, Irkens see with vision tinted to the color of their eyes. There is no known explanation for this, and the color shift can be viewed as disadvantageous, given the possibility of certain objects becoming less noticeable or nearly invisible. There is a possibility that the color tint is an attempt to keep Irkens away from artistic pursuits, which are frowned upon, by partially removing their ability to distinguish colors different from that of their eyes.

How Irkens hear is a topic that has been debated for awhile; with the two most popular hearing mechanisms being either the antennae or inner ears. What is known is that Irkens antennae are capable of mild thermoception, the ability to sense heat and the absence of it (cold). The antennae are not truly comparable to human ears because, although Irkens pick up sound vibrations with their antennae, they do not perform all of the functions that a human ear does, as the Irken antennae does incorporate any sense of balance. However, hearing is considered a separate sense from equilibrioception. Balance is kept in a way similar to humans, with an internal, fluid filled canal located close to the sides of an Irken's head; a partial inner ear. The vestibular sense is also imitated by the PAK, which uses a series of gyroscopes to determine orientation.

An Irken's sense of taste is arguably a largely useless sense. Because Irkens do not need to eat to live and only do so for their own pleasure, they do not truly need the ability to taste but desire it. However, since shortly after the creation of cloning techniques and the mapping of Irken DNA, it has been argued that Irkens should modify their ability to taste to remove the receptors for sourness and bitterness. The counterargument to this is that some Irkens enjoy the use of those taste buds and that Irkens actually do have the freedom to chose which snacks they enjoy eating. There has also been the occasional suggestion of removing the ability to taste salt, though there are no records that there has ever been a proposal to remove the receptors for sweetness and umami (savoriness).

Irkens have a largely stunted sense of smell, as it was found to be the easiest solution to the problem of unsavory smells caused by all the chemicals and factories on Irken planets. Although Irkens do not have a visible nose, there is a permeable area of the skin located approximately where a nose would be; slightly below the center line between the eyes. In order to smell something, Irkens need to be close to the object, within a foot at least and usually even closer.

Irkens also have an artificially stunted and heightened sense of touch. It is not a change that was made at a genetic level but by the Irken lifestyle. By wearing full body uniforms from smeethood, Irken skin rarely comes into contact with anything that is not their uniform or a substance used for personal hygiene. The Irken sense of tactition is therefore largely useless because of the lack of contact they are allowed. However, should an Irken's flesh come in to contact with a new object, their senses are comparatively heightened because the experience of touch is a relatively new one for the individual Irken and they therefore gather more information than they otherwise would because they have not lost physical sensitivity.

An Irken's PAK can artificially perceive other senses outside of the basic five. The PAK, with its ability to scan for injuries and other medical problems, creates a sense of nociception, the perception of damage or near-damage to tissue (skin, joints and bones, and bodily organs). The Irkens physical body usually does not perceive pain, except in brief flashes at the time that injury is incurred, because of the PAK's ability to heal its host body and its ability to either infuse pain killers in to the host's body or to disconnect the host's ability to perceive pain (a dangerous practice, because an Irken could then unknowingly push their body past its limits and perhaps beyond the PAK's healing abilities).

The PAK also handles proprioception, the awareness of where various regions of the body are located at any one time. This helps to handle balance and coordination as well as allows an Irken to rely on their PAK enhancements (their extra mechanical legs, in particular) without having to consciously keep track of the extra appendages.

Both the PAK and the antennae have a highly developed sense of electroception, the ability to detect electric fields. Although the antennae are very useful in this perception, the information gathered by them on electrical fields is handled by the PAK. This is because Irken planets are extraordinarily mechanically advanced and any given area is likely to be generating multiple electrical fields. The massive amount of sensatory data is therefore handled by the PAK, which classifies electrical pulses with Irkens signal patterns as low priority data, which is almost entirely ignored unless a fluctuational anomaly is found in the signal. The PAK deals largely with electrical fields that are not a product of Irken machinery, monitoring the number of electrical fields in range of an Irken and the strength and source of each. There are two reasons for the highly advanced nature of this sense, the first being the potential danger of an electrical field to an Irken. Although a PAK is designed to be able to absorb and protect itself from large doses of foreign electricity, a strong enough shock will damage a PAK. The ability to sense electrical fields allows an Irken to be aware of imminent PAK danger and to leave the range of the dangerous field or fields. The second use of this sense is to allow Irkens on enemy planets to find any weapon advanced enough to create an electrical field and either destroy it or take it for their own use.

The PAK and antennae can also work in tandem to create a sense of echolocation. The antennae already have the ability to sense sound vibrations, so the PAK simply needs to send out a sound wave so that the Irken has something to listen for. Again, this sense is especially useful on enemy planets, where operations may be held under the cover of darkness and an Irken is unlikely to known the terrain very well.

In addition to a homing chip inside the PAK, the PAK can be useful in navigating if it can detect and interpret a planet's magnetic field. It is unwise to rely on a PAK's magnetoception, however, because it usually picks up too many other, smaller magnetic fields to be able to make a clear map. In addition, magnetoception is primarily used for long distance travel, usually for migratory purposes. For an Irken to move that sort of distance, they would be almost guaranteed to be using Irken equipment with proper guidance systems far more accurate than a PAK's magnetoception.

The PAK is also capable of pressure detection, a very useful mechanism for maintaining pressure equilibrium for space armor.

---

Next section: Life Cycle (unless someone reminds me I need to write something that I haven't written yet and logically goes before life cycle)

Also, it was very annoying to figure out an Irkens range of vision. But I did do it using a real formula: Total degrees of vision for each eye minus visual overlap between eyes equals the number of unique visual degrees for each eye. Take the total degrees of vision for each eye (the last number you got times two) and add it to the degree of overlap to get total visual range. For humans the math is: 135-9045. 45+45+90180. So using the numbers I plugged in for Irkens it becomes: 210-12070. 70+70+120260.