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Daraz Biology: Infrared Vision

Daraz Biology: Infrared Vision published on

Valley of the Silk Sky - Hali

The Daraz are primarily a subterranean species, and have poor eyesight as a result. They rely more on sonar for navigation (hence those big ears), but what they do see is in the infrared spectrum.

The dots just below the Daraz’s eyes are pit organs, which sense infrared light as heat (similar to how a pit viper detects warm objects). The heat information gleaned from the pit organs is ultimately processed by the same part of the brain as the eyes (again, similar to pit vipers).

A heat imprint can last for several minutes. If, say, a person was sitting in a chair but got up and left the room, the body heat they imparted to the chair would still be visible in infrared until the chair returns to room temperature.

Valley of the Silk Sky - Infrared VisionWhile infrared vision registers heat, infrared is actually a wavelength of light, and it behaves differently from visible light in several notable respects: water and glass both appear opaque in infrared, and extremely smooth surfaces can have a mirror-like reflection, even if they’re made of wood or stone.

Because sight is considered a lesser sense by the Daraz, their idioms reflect their preference for hearing and smell. So, while a human might say, “I see what you mean,” the Daraz would instead say, “I hear you on that,” or “I catch the scent of it.”

Daraz Biology: Flehmen Response

Daraz Biology: Flehmen Response published on

Valley of the Silk Sky - flehmen response

The Daraz have a vomeronasal organ, located near the roof of the mouth. There’s smelling with the nose like a noob, and then there’s the flehmen response, wherein a sharp inhalation pulls air over the vomeronasal organ to allow a deeper read of a scent.

In mammals the flehmen response is typically used for sensing pheromone information from another mammal of the same species, and is related to reproductive activity.

Because the Daraz Harcos are non-reproducing members of their species, they care not about reproductive activity. Instead, given that they are the primary hunters and defenders for the Daraz, their flehmen response is used to gather other types of information: Is this something I want to eat? Is it a predator I need to avoid or fend off? Was the scent made an hour ago, or a few days ago?

All good things to know if you’re trying to track, say, a young charge who got lost in the wilderness. Just to throw a random example out there.

Daraz Biology: Body Type and Caste

Daraz Biology: Body Type and Caste published on
Valley of the Silk Sky - Daraz Biology
Daraz Harcos

These creatures are a species known as the Daraz, and they are monotremes, a.k.a. egg-laying mammals. The Daraz come in four basic body types: Kiralyno (a.k.a. The Kira, the primary egg-layer); Hazastars (consorts to The Kira who are involved in reproduction); Munkas (non-reproducing laborers); and Harcos (non-reproducing warrior/hunters).

Of these, the only ones humans are ever likely to see are the Harcos, as the rest typically stay underground for most of their lives.

Your body type, and therefore your caste, is preselected at egg-laying based on what the clan needs most. Every egg has the potential to be any body type. Which one it grows into is determined mostly by what the embryo is fed while it is developing in the cell. Some will get a diet rich in thus and such hormone, and become breeding adults. Others will get a different hormone, and become non-breeding workers.

Daraz society is collectivist – you have a job to do for the good of the clan as a whole, and there’s not much room to decide you want to do something else. After all, if you’re a non-breeding worker caste, you do not have a reproductive system (beyond some vestigial internal organs). You can’t decide you want to be a breeding adult instead. If you are a Harcos your body is literally a weapon, and you will be expected to train in how to use it so you don’t hurt those around you just by existing.


Ah, but biology is complex and prone to unpredictable variation, and as such this predetermination process doesn’t work smoothly 100% of the time. Up until about 6 weeks of gestation you can switch production over to a different body type without noticeable consequence. After a somewhat vague cutoff point, though, you wind up with someone who is a little bit this and a little bit that. These Daraz are known as “Keverek,” a.k.a. “mixed.” In these cases, you’re assigned to the caste you seem most similar to, and everyone just sort of hopes it works out.

Hali is one of these Keverek. Xe started out on the path to being a Hazastar, but a sudden need for more Harcos had xer production shifted fairly late in the game. Since Hazastars are significantly smaller and less muscular than warrior/hunters, Hali is shorter and thinner than xer compatriots. (Xe is also much younger than the other two in the illustration, who are adults tasked with training the up-and-comers.) Given that xe has all the Harcos weaponry and no evidence of a functional reproductive system, xe was assigned to the Harcos caste, and off to training xe goes.

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