Why I’ve Chosen Not to Handwave: The fictional galaxy in which this humanoid species (I’ll refer to them as Empaths from here on out) lives is protected by a space-faring military/law-enforcing legion of mostly humans (descendants of ‘Terrans’) with a healthy dash of various alien species mixed in. Human civilians, and non-civilians, have spread throughout several systems from the planet that they colonized long ago after leaving Earth and I figure it’s a given that a good number of them would’ve taken it upon themselves to figure out how and why their ‘neighbors’ work by now.
Even after considering this, I might’ve just handwaved the odd markings of the Empaths, referring to them in a completely offhanded, romantic sense rather than getting technical about it at all, but the focus of these stories is crews in the aforementioned legion and I intend to make members of many of the alien species that I’ve conceived a part of these crews. One crew-member that I came up with is half human, half-Empath and, having already decided that the Empaths would have teardrop shaped markings beneath their eyes, I had to wonder if he would too.
At first, I thought that maybe his would just be fainter than the bold markings that full blooded empaths have, but then it occurred to me that the teardrops could be linked to the empathic abilities of this species. So, let’s say that a rare few Empaths are born without the ability to sense the emotions of other beings (this would be considered a very rare birth defect): they wouldn’t have the teardrop markings. The half breed has inherited empathic abilities from his Empath parent, though, so he has the markings and they are just as bold as those of full blooded Empaths, because he has them.
My Question: I considered that the abilities of the Empath species might be the result of a ‘xeno-chemical’ (?), but I have no idea how or why this chemical (which may be produced by their brains or come from a unique organ?) would create teardrop shaped markings on the faces of these aliens. All answers are welcome, be they musings or lectures. I am, however, hoping for a biological explanation for these markings.
Further Info on Empaths: The teardrop markings are bold black; I haven’t decided yet how many I want each Empath to have or if the number will vary (like freckles), but I am fairly certain that they will be beneath the outer edge of both eyes, most likely side by side, as opposed to one beneath another. Concerning the empathic abilities of these aliens, the vast majority can clearly read emotions when touching another sentient being and vaguely sense them when their proximity is close. The most sensitive among them can clearly read emotions through close proximity and vaguely sense them from, say, two feet away. They are raised to suppress their ability to sense emotions by close proximity (shut it out, like meditating) and avoid physical contact with one another, except in situations dictated by tradition - It would be considered very bad manners to ask someone standing right next to you at an Empath party why they’re suddenly angry if you didn’t notice the man’s ex-girlfriend just walk in with another guy and he knows he didn’t let it show on his face, and so on.
Clarification: To those that have suggested tattoos; I never intended for the teardrop markings to be anything other than natural. I apologize for not making this clearer when I originally posted this question and, yes, I realize that tattoos are the simplest explanation, but, no matter what decision I come to regarding these markings, I will be sticking to the ‘fact’ that the Empaths are born with them. Nevertheless, thank you for taking a whack at it.