Visual Arrest

and how many deep-sea creatures evolved to be red as a stealth adaptation, making them near invisible when there’s little to no light present

and it makes me think. If there’s never any visible light present in these animals’ lifetimes, if no ROV shines a little flashlight in depths that would otherwise not have light, would these animals ever get the opportunity to actually be red? that might be a stupid question.

Like is color physiological and determined by the shape of whatever pigment cells that will always absorb certain wavelengths and reflect others?

or is color meaningless if there’s no light to absorb and reflect?

Is it completely relative because the way we percieve color is subjective, how even within our own species there are so many different kinds of ways people can observe color?

The stomiidae, which include the viperfish, dragonfish, and loosejaws, are one example of a deep sea animal that evolved to perceive and produce red light because it isn’t naturally present in their environment and most other organisms never hit on that adaptation. In most of this group, tiny red lights can be switched on and off throughout their skin to communicate with their own kind in secret. More threateningly, some of them have high-powered “floodlights” of pure red just beneath their eyes; almost no other deep sea fish emit actual BEAMS of light to illuminate what they’re looking at because that’d make them a shining beacon to every larger predator in the area, but since it’s red, the only risk ends up coming from their fellow red-light hunters and those remain just uncommon enough to be worth the chance. In many members of this group, most of all the loosejaws (hence the name), almost the entire skull can naturally detach from the rest of the body on specialized stalks at lightning speed so that their long, hooked jaws can grab prey in an instant, almost the same exact motion as the arm of a preying mantis:

And food is so far between, the predators need even longer teeth, to make sure those rare meals they encounter really can’t escape:

And because it’s dark AND food is scarce, they need big, expandable jaws and bodies that are almost all stomach, to guarantee they can take advantage of more meals and don’t have too much more body to have to nourish:

The most surprising thing about these features, however, is that they’re already present in many of the fish people are familiar with! The loosejaw pushes it to an extreme, but you can see how these freshwater carp also “unfurl” and “throw” their jaw structure:

The loosejaw just doesn’t have a skin covering this structure, because that allows it to fling the jaw even faster through the water with no resistance! …And it’s also quite normal for all kinds of everyday fish to have additional teeth or a functional secondary set of jaws in the back of the throat: