- Oct 15, 2005
The example I was thinking of was that there's a clip on one of the ceph documentaries where someone puts a cuttle in a tank with some of that garishly colored goldfish bowl gravel (like yellow and purple or something" and the cuttle matches the texture, but misses the colors completely. But I tried to generalize it to the idea that studying camouflage in general needs to be done by looking at the environment in which the creature uses it... I would normally say this is over a large number of generations, but there's a famous example of moths in Britain during the industrial revolution who rapidly changed their coloration over a small number of years to match the soot spewed by coal-fired industry, so I guess it can change on a pretty rapid timescale. Of course, in a tank, there's no penalty for having bad camouflage, because there are no predators, so there's not a lot of selection pressure to adapt the camouflage to the tank, while the moth example presumably happened because once there was a lot of soot in the environment, all the light-colored moths were eaten by sharp-eyed birds before they had a chance to reproduce.dwhatley;94378 said:Monty,
Can you layman that a little? When you say "move the cuttle to an environment different from where it evolved" are you speaking of evolution or simply several (or immediate) generations? My interest is in my bandensis'. If their (immediate) parents envionment is crutial to maximizing their color change, should I be investigating the environment "colors" of the Phillipines to maximize their ability and possibly their health or are you saying they can't turn swimming pool blue if the tank was barebones with a blue background since that color is not found on reefs in general?
If octopuses are colour blind... how could they change colour to match the background? The answer may be that they do not change colour with the chromatophores but rather the brightness (or luminance) of their skin. In the process of adjusting the brightness, they reveal more or fewer of the underlying reflecting cells and it is these that assist the animal in matching the background in colour.
Octopuses cannot use their chromatophores to match all the colors in their world because their pigments are restricted; they are black, brown, red, orange, or yellow, never green, cyan, blue or violet. Such chromatophores could never match the blues of a limestone grotto or the greens of algae in a shallow pool. Yet in life octopuses can take on the colour of their surroundings...