Cuttlefish Question

ManaUser · Post by **ManaUser** » Thu Apr 06, 2006 5:37 pm

Since we have a cephalopod expert here... I was reading about cuttlefish (on Wikipedia, so grain of salt taken) and it says they can't see color. But they can camouflage in color, so if they can't see color, how do they know what color to turn? Or am I wrong in assuming they do?

Honor · Post by **Honor** » Thu Apr 06, 2006 6:21 pm

*foamy voice* Gooood Question!

Squidflakes · Post by **Squidflakes** » Thu Apr 06, 2006 6:24 pm

They can't see color, they can only see horizontal and vertical polorized light. If you ever look through those glasses they sell in the sporting goods section, thats sort of what its like, only colorless.

Anyway, the color change is involuentary and it matches their background in tone, but not always color. See, most cuttlefish predators are color blind as well, so as long as the tone matches, the cuttle will look just like the background.

When I left the NRCC, we were doing experements on just this question. During the experement, I saw a cuddle hover over some brown and white stripes of rock that were the same tone, just different colors. The cuddle turned a mottled yellow and was vividly visable to us the researchers, but though the "cuttlecam" (a black and white camera with polorized lens filters, off-set 90 degrees from one another) it was just like looking at the clear bottom.

The question still remains though, how do the cuttles match a bottom they really can't see. By that I mean, sections of bottom that are under them, but out of their field of vision.

Aeridus · Post by **Aeridus** » Thu Apr 06, 2006 6:25 pm

It's still possible to distinguish colors based on shades of grey...

Edit: Squiddy beat me to it.

Awkwardschoolgirl · Post by **Awkwardschoolgirl** » Thu Apr 06, 2006 6:41 pm

squidflakes wrote: The cuddle turned a mottled yellow and was vividly visable to us the researchers, but though the "cuttlecam" (a black and white camera with polorized lens filters, off-set 90 degrees from one another) it was just like looking at the clear bottom.

*giggle* Freudian slip?

"Would you cuddle me so much... you could be mistaken for a... cuddlefish?" *groan*

Squidflakes · Post by **Squidflakes** » Thu Apr 06, 2006 6:46 pm

awkwardschoolgirl wrote:
squidflakes wrote: The cuddle turned a mottled yellow and was vividly visable to us the researchers, but though the "cuttlecam" (a black and white camera with polorized lens filters, off-set 90 degrees from one another) it was just like looking at the clear bottom.
*giggle* Freudian slip?

"Would you cuddle me so much... you could be mistaken for a... cuddlefish?" *groan*

Yes.. yes I would

Chiropteran · Post by **Chiropteran** » Thu Apr 06, 2006 7:09 pm

Saw someting on public TV once, where they put a cuttlefish in a tank with a black and white checkered floor and it turned checkered; it wasn't as sharp, but then they're evolved for copying organic things, not straight lines.

ManaUser · Post by **ManaUser** » Thu Apr 06, 2006 7:26 pm

squidflakes wrote:Anyway, the color change is involuentary and it matches their background in tone, but not always color. See, most cuttlefish predators are color blind as well, so as long as the tone matches, the cuttle will look just like the background.

I suppose that's about what I would have guessed. Kind of interesting that they can change color, not just shades of gray, but can't tell the difference themselves though.

squidflakes wrote:The question still remains though, how do the cuttles match a bottom they really can't see. By that I mean, sections of bottom that are under them, but out of their field of vision.

It seems the only possible answer is that they look at it ahead of time and "remember". Or has there been any suggestion that they can see in some limited way with an organ other than their eyes?

Squidflakes · Post by **Squidflakes** » Thu Apr 06, 2006 7:39 pm

The looking ahead and remembering theory was promoted for a while, but they can color change on the fly while moving backwards where they wouldn't be able to see the upcoming terrain.

Some have suggested that there are sense organs in their skin, but I think the better answer is that they have a wider field of vision than we suspect.

Squidflakes · Post by **Squidflakes** » Thu Apr 06, 2006 7:40 pm

Chiropteran wrote:Saw someting on public TV once, where they put a cuttlefish in a tank with a black and white checkered floor and it turned checkered; it wasn't as sharp, but then they're evolved for copying organic things, not straight lines.

We put one of those old fashioned TV test patterns on the floor of one of the tanks, and had a pretty good time watching that. Cuttlefish really are nature's silly putty.

Queenhank · Post by **Queenhank** » Thu Apr 06, 2006 8:07 pm

Well, the eye isn't the only photo-sensitive organ. Even on humans, it has been discovered that the skin on the back of the knee is photo-sensitive. Perhaps cuttlefish have something similar going on?

Squidflakes · Post by **Squidflakes** » Thu Apr 06, 2006 8:23 pm

queenhank wrote:Well, the eye isn't the only photo-sensitive organ. Even on humans, it has been discovered that the skin on the back of the knee is photo-sensitive. Perhaps cuttlefish have something similar going on?

Its possible. I'd like to read where you got this information on the knee skin.

Aeridus · Post by **Aeridus** » Thu Apr 06, 2006 8:45 pm

That's... unusual...

So is that part of our "sixth sense" then? Might explain why sometimes we can tell when people are watching us.

Queenhank · Post by **Queenhank** » Thu Apr 06, 2006 9:00 pm

Man, I never remember where I get information from. I'm just really full of trivia. I probably read it in some magazine, like National Geographic, Time, or something similar.

Tellner · Post by **Tellner** » Thu Apr 06, 2006 9:34 pm

Makes sense. If you go down a few feet most of the color just washes out and color vision isn't that useful. Tone is much more important.

Nithos · Post by **Nithos** » Thu Apr 06, 2006 9:57 pm

The color receptors in ou eyes are also less sensitive, which makes monochromatic vision better in the dark than color vision.

ManaUser · Post by **ManaUser** » Thu Apr 06, 2006 10:25 pm

queenhank wrote:Man, I never remember where I get information from. I'm just really full of trivia. I probably read it in some magazine, like National Geographic, Time, or something similar.

Here we go.

Jackalope · Post by **Jackalope** » Thu Apr 06, 2006 11:45 pm

Yup, that's it. And ties in with some other research that suggests that near-UV exposure on the skin plays a role in depression as well as vitamin-D deficiency. Since I'm a cave dweller by medical necessity, I do tend to keep up on these studies. However, my sleep/wake cycles were whacked out long before I had to start avoiding the sun, which would suggest other factors at play as well.

Aeridus · Post by **Aeridus** » Fri Apr 07, 2006 5:56 am

I wonder if we could eventually invent more natural artificial light that more closely approximates what we get from the sun? It would certainly make people who work in offices all day a lot healthier.

Error of Logic · Post by **Error of Logic** » Fri Apr 07, 2006 6:29 am

It'd be easier on the old eyes, too. Some of those fluorescent lights really hurt; my eyes are a bit too sensitive sometimes.