In my continuing search for unknown unknowns I just read Octopus!: The Most Mysterious Creature in the Sea, by Katherine Courage. This creature has a close genetic relationship with the nautilus, squid, cuttlefish, and each of these mollusks known as Cephalopods has astonishing, genetically inherited abilities for camouflage. These creatures live short lives, eating voraciously and growing rapidly, and generally dying shortly after reproducing. My particular interest is, how did these short-lived masses of muscles evolve their substantial intelligence and camouflage abilities? The problem is curious because they tend to live solitary lives where they can learn little from their compatriots. Whenever one of these individuals learns something it learns from personal experience. They can occasionally learn from observation of other cephalopods, but this is risky, because typically when they see another cephalopod their goal is to eat them, but avoid being eaten themselves; and for the male, the problem is compounded, because to mate is to commit suicide, as they soon die.
In my post on cuttlefish I considered the possibility that some male cuttlefishes’ ability to disguise themselves as females, and thus slip past the jousting bigger male cuttlefish, and secretly mate with the females, was the key selective factor for camouflage. That may be the driving factor in the cuttlefish’s extraordinary ability of disguise, arrived at genetically by evolution. The assumption being that the evolution for the ability for seeing these abilities by the females went along with the ability to create the disguises by the males. Evolutionarily both sexes would benefit from both abilities; first both would gain improved ability to better disguise themselves from predators and prey, and second they would gain better perceptual abilities for seeing camouflage to better cope with their world.
The alternate forcing factors for creating these evolutionarily developed disguises would be gained from the predators upon the cuttlefish and octopuses, by improving their ability to see through the disguise deceptions and eat them. Thus, a selective pressure of the survivors being those who reproduced, and thus the evolution of better disguise by the cuttlefish and the evolution of perceptive abilities by their predators. The problem with that idea is that the cuttlefish and the other cephalopods are tasty meals loved by all meat-eating animals. They have many predators who want to eat them, and all, or at least many, of these predators would have to evolve better perception, or go hungry.
It would seem the females of the species were more likely to be forcing the selective processes, rather than the predators, because they were getting the maximum benefits from doing so; they were surviving better because they weren’t being eaten so often, and they were surviving better because they were eating better. They could eat better because their successful disguise would allow them to capture prey more easily.
Unfortunately, for my quest, this book didn’t dwell on the selection processes enough to help, but it was a delightful read, and I know a lot more about octopuses in general.
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