Traits

In some animals the protective layer on their eyes is a darker color, possibly even black in appearance. This adaptation is theorized to hide eye movements in predators or even act as 'gaze camouflage' for social species hiding where they may be looking from others around!

Life in a world of little-to-no light can present several obstacles, arguably the most important being how to sense the enviroment. Hollow Xeros have developed eyes that feature significantly larger pupils and a highly efficient tapetum. These features enable them to operate effectively in the darkest of conditions and give their eyes a soft, reflective sheen.

Some Xeros may have thin, slit pupils instead of the standard round or oval ones. This is an uncommon adaptation, but the Xeros that have this style of eye tend to have even stronger night vision. 

In some Xeros, the tapetum lucidum that gives them such excellent low-light vision undergoes a dramatic mutation. Bright pupils are the result of this highly reflective tissue, causing it to reflect in such a manner to create this striking appearance! This trait allows a Xero's pupils to be lighter in color than the iris (the main colored part of the eye). The bright pupils can be any color, so long as they are lighter in value than the iris.

While Xeros typically feature a static pupil, their flexible biology can be manipulated to overcome this limitation. By altering the smooth muscles of the eye, the collarette can be reshaped effectively, changing the shape until desired.

Though it's very rare, some Xeros may have horizontal pupils instead of the standard round or oval ones. This strange adaptation gives the Xero a wider field of view, making them very hard to sneak up on.

Eye stalks are classified as two protrusions from the head of a Xero that have a cone-like base and two round eyes on top. These stalk eyes are simple ocelli and are primarily used to detect light, dark, and movement all around the Xero, rather than complex shapes or colors. Sneaking up on a Xero with this trait would be very difficult!

Eye stalks must be placed on top of the Xero's head area and must be in pairs, much like adding any other extra body part. The eyes must also match the iris and pupil color of the rest of the eyes on the Xero, meaning that if a Xero has blue irises, the stalks must follow suit!

These ears are unique to Hollow Xeros, and while they fit the shapes and sizes you expect from a standard Xero, they do have an adaptation unique to their type. The ear's interior cartilage is ridged, acting as a type of acoustic focusing lens to help sharpen sounds for positional accuracy in the dark. Hollow ears can be a solid color, or have a gradient of changing colors within the different segments. The ridges within the ear must be present.

Frilled Ears are a rare mutation observed on Xeros. They have a grooved outer edge, giving them a jagged or wing-like appearance.  

Desert Xeros can have larger than average ears to radiate heat, this trait is known as Desert Ears. They can be any shape (pointy fennec-like, rounded jackrabbit-like, etc.) Size can vary a bit, but is generally about 1.5 to 2x the height of the head.

Tundra Xeros can have extremely fluffy ears called Tundra Ears; the fluff is so long that the tufts of fur inside cover most or all of the visible skin and hangs outside the ears!

Folded Ears are a common mutation observed on Xeros. These ears can be various shapes and sizes depending on other mutations present, but feature ears that are bent or folded in some way.

Tufted Ears are a common mutation observed on Xeros. These ears can be any shape or size, but feature tufts of longer fur at the tips. This adaptation may have allowed Xeros to more easily determine wind direction and stay downwind of danger.

Lop Ears are an uncommon mutation observed on Xeros. Xeros with these ears lack structural cartilage and muscle control, leading to fully hanging ears like the ears of a lop rabbit.

Round Ears are a unusual mutation observed on Xeros. These ears are very circular in shape, rather than the elongated, diamond-like shape Xero ears typically are.

Marine Xeros can have extra small ears, or no visible ear flaps at all. This adaptation helps them be more streamlined underwater. If combined with the Marine Fin trait, they can have fins instead of ears!

Flat pads that cover the entire palm and sole of their paws allow Woodland Xeros to grip onto bark and foliage with ease while climbing, allowing them to get to higher elevations quicker. These pads are covered in the same setae as standard Xero paws, but the higher coverage gives them enhanced grip.

Horns are a rare trait for a Xero to have; these keratin-covered bones grow in pairs from the top of the Xero's head. Much like the antennae, horns can be many different shapes and lengths. Horns can only be found in symmetrical pairs and only on the top of the Xero's head; for keratinous growths on other areas of the Xero's body, see the Spines trait.

Marine Xeros can have fins of any sort on various parts of their bodies. Fins can include whale-like dorsal fins and flukes, shark or fish-like tails, or any other sort of webbed fin. Fins can be located on their backs, tails, backs of their limbs, or even in place of their ears, if also given the Marine Ear trait.

Spines are a somewhat uncommon trait for a Xero to have; these keratinous protrusions are hard, shiny, and slightly translucent, just like the Xero's claws. Spines can be many different shapes and lengths, and can be present on the body of a Xero. Spines are often found on the back, tail, cheeks, or nose, as well as other places such as the back of the limbs. They cannot be placed on the forehead area of a Xero, see the Horns trait instead.