I’m in the process of making my own original series where I have all types of biologically feasible cryptids and monsters in it. In this series, I’m planning on having vampires being a species that broke off of humans at some point in our evolution. I was thinking homo erectus but more on that in a future question.
But basically I’m having them be a more carnivorous species than us, that evolved to be nocturnal. And some of the adaptations I came up with are cooler body temperatures, pale skin, and most interestingly, black sclera. Does anybody have any idea if it’s even possible for sclera to be black? I was thinking it’d be caused by a mutation that helped hide the whites of their eyes (seeing as how we evolved to show so much of our own sclera so others could tell where we were looking so with this, it’d be harder for their prey to tell where they’re looking). Or do you think it’d be more possible to make them voluntarily turn their sclera black when they’re hunting, similar to how chameleons and cephalopods can?