Colorvision

[johfro]

Hello all!

Does anyone know if octopuses have colorvision or do the only see b/w?

/johfro

[OctopusV]

From what I've heard, they're colorblind. That's supposed to be why their clor change repetoire is so amazing.

[Burstsovenergy24]

Ive heard they are colorblind too. . . (And so am I :cry: )

[Snafflehound]

if they are colour blind how can they tell that they are changing colour? :rainbow:

[Burstsovenergy24]

Maybe they see everything in 0's and 1's. . .

(Like me. . . j/k) :heee:

[joel_ang]

We're not too sure, but we think that they see colours in different shades of grey, to match they put on the same colours as what they see. But its a theory and we're not 100% sure.

[Nancy]

I believe I saw a reference to a recent investigation showing that octopuses could distinguish between blue and pink.

At any rate, I think we'll be hearing more about this - there has to be some way they can match colors around them so well, and grays won't do it! Those of you who have kept octopuses know that they can disappear by matching the rock around them, even when it's colorful with coralline algae.

Nancy

[Latina]

I am by no means a science major, but if I remember correctly from my days in Bio 1 and Bio 2, an Octopus's/Squid's eyes are just as complex as the human eye. Based on that, we do know for sure that their eyes are light sensitive and are definitely able to see in black and white. And if I'm know mistaken, they are only able to change to colors because they see on a gray scale. But nobody knows everything...

If I'm wrong about this, let me know!
Ciao! :rainbow:

[Architeuthis]

Octopus eyes can only see in black and white, at least thats what I've heard. They do, however, have pretty good night vision. And I believe they have some sort of sensors that work with the chromataphores. :?:

[monty]

Octopus eyes can only see in black and white, at least thats what I've heard. They do, however, have pretty good night vision. And I believe they have some sort of sensors that work with the chromataphores. :?:

I have also read/seen the claim that cephalopods can only see in black and white, although I haven't heard of any "sensors that work with the cromataphores"; I know that cuttlefish use their eyesight to match the environment-- blind cuttlefish lose their camouflage abilities. There is some TV show that demonstrates that they can only match the texture, rather than the color, when put in a tank with garish yellow and blue goldfish-bowl rocks.

More for the vision thread, though, it has been shown that octopi, at least, can see polarization of light... if I remember right, there were also experiments that showed that they could distinguish between horizontal and vertical lines ( - | ) but not left-diagonal and right-diagonal ( / \ ).

[joel_ang]

Apparently octopuses can distinguish only certain colours, to them, red and green look the same. Probably a reason why you don't see live green octos.

[cthulhu77]

Well, to say that any animal is "color-blind" is a rather misleading statement...early dissections theorized that since non H.sapiens eyes don't have the same structure, of course the eye must be more primitive or lacking the ability to see in colour.
I can't say much about cephalopod eyes...I never dissected one (spent all my semester lab time on the muscle structure of loligo beaks) , but I have found out that a lot of "accepted" truths are based in broo-hoo-ha.
I am sure one of our academics can put this issue to rest. :grad:
greg

[Burstsovenergy24]

Apparently octopuses can distinguish only certain colors, to them, red and green look the same.

LOL! Same as me. :|

[cthulhu77]

Hehe...BOE, we should put you in a tank and see if you can change your skin texture too! What a great superhero you would be!
"It's Cuttleman!"

[Burstsovenergy24]

I dont know whether to be pissed or laughing. :|

[um...]

Do you have an ink sac too, Cuttleman?

:cuttle:

[joel_ang]

so ure red green colour blind?

[Burstsovenergy24]

Yeah (http://www.toledo-bend.com/colorblind/Ishihara.html).

[Snafflehound]

Hey BOE nice color page!

I can see all of the numbers... but on the last one

http://www.toledo-bend.com/colorblind/Color5-2.jpg

I see the 5, but if I squint my eyes almost shut, the 5 turns into the 2. :bugout:

Does squinting affect colour vision or is it something else :?: at work

[Burstsovenergy24]

I dont know. It only looks like a 2 to me. :)

Oh and check this out: See your web site through colorblind eyes with the colorblind web page filter. (http://colorfilter.wickline.org/colorblind/filter/button)

Mine is the deutanomaly (anomalous green cones) setting; although, my cones are slightly less anomalous than that shows. :)

[cthulhu77]

Oh, don't be pissed... :D
If you squint, you change your intake of focal light, and compress it to hit more on the colour receptors of the back of your eye...if you widen your eyes, you gain a better black/white/movement vision.
Gosh, we certainly are simple animals!
greg

[WhiteKiboko]

well, someone could try a experiment... always put some food behind a door with the same number.... then play around with patterns that have the same intensity, etc...

as for myself, for the first .5 sec i see a '3' when i look at the five

[Burstsovenergy24]

I see an upside 3 if I look hard enough. :)

[joel_ang]

I can vaguely see the 2 ... :)

So does the page appear grey and white?

[cthulhu77]

Oh, stop with all of the kidding...anyone can tell that it is a slightly pixelated version of the Sistine Chapel...I mean, look at the naked girls!
greg

[Burstsovenergy24]

:lol:



Joel, no:


Oh and check this out: See your web site through colorblind eyes with the colorblind web page filter. (http://colorfilter.wickline.org/colorblind/filter/button)

Mine is the deutanomaly (anomalous green cones) setting; although, my cones are slightly less anomalous than that shows. :)

Thatll show you this page through my eyes. :) Not very different but for somethings it matters.

[Nancy]

Our home page looks pretty dull using that filter - I guess you get used to not seeing certain colors and compensate.

Nancy

[Burstsovenergy24]

LOL. I guess. Its a nice looking page to me. :)

[joel_ang]

So that means you see that colour filtered page as we normally see it?

[Burstsovenergy24]

No. . .

You see the filtered page as I see it.

[joel_ang]

OIC, i was a tad confused...

[Fujisawas Sake]

My :twocents: :

The cephalopod eye is a miracle of engineering, and its a design that shows convergent evolution at its finest.

The general vertebrate eye (let's use our own for example) :cyclops: has a set of cells; they are rods and cones. Light enters the eye, passes through a layer of glial cells, and hits said rods and cones thus producing the signal that is read by our brain as "sight". (mind you, I'm really oversimplifying this due to the fact that I tend to get over-scientific at times :oops: )

The ceph eye has no rods nor cones. What they do have are photoreceptors (light-gathering cells) called rhabdomeres, which pretty much take the place of our rods and cones. Light passes directly through the lens and is collected by these photoreceptors. The pigments in these structures move with the light, and the lens is actually controlled by muscles, drawn in or out to focus on objects at various distances. So, no, they cannot "see" color, but can discern various shades of light intensity and therefore can probably percieve what we consider mere black and white into much more.

A lot also has to do with the number of cells per square millimeter of retinal tissue, and the fact that the cephalopod brain has a huge section of resources dedicated to optics and sight.

So they don't see true "color", but they pretty much discern it. At least, that's the way I see it.

John

[Phil]

Thankyou for spelling that out in black and white for us, John. Very interesting.

Phil

[Burstsovenergy24]

:notworth:

[Fujisawas Sake]

BoE24...

Badger, badger, badger, badger....

MUSHROOM MUSHROOM!!

:mrgreen:

John

[octosquink]

I am quite bothered by the fact that I see a 2. I am a girl and I KNOW I don't have red/green color blindness. Now I am freaking out, thanks.

[Burstsovenergy24]

Did you take the Ishihara Test?


While its unlikely for a woman to be colorblind, its possible.

[WhiteKiboko]

So watching Ishtar makes you colour blind?

[cthulhu77]

watching that film will make you blind, the retinal damage is incredible!

[Fujisawas Sake]

Okay, here comes some more science, folks! :grad: Sorry...

Something occured to me today, thanks to my physiology instructor... An interesting sidenote to the concepts about the eye has yet to be mentioned - selective pressure and its effects on form and function.

Our eyes use the aforementioned glial cells to process the sensory information early (before the rods and cones get hit by light). This way, they do a lot of the work saving the brain some energy (and work). I wonder if this is partially how hallucinations work? But I digress...

The ceph eye has no pre-processing, so the light goes right to the rhabdomeres, right? Animals on land that depend heavily on light-gathering eyes (nocturnals mostly), usually have less color vision or see in "black and white". I think this may be due to the tapetum lucidum (the silvery film that reflects light in vertebrates - think how cats eyes seem to "glow") and that night vision tends to sacrifice color for view.

Where do cephs live? Water pretty much blows when it comes to conducting light as well as air. The photic zone is what... about 100 meters or so? Cephs need light resolution far more than color vision, and also, color tends to get warped in the water. If you have eyes like a vertebrate, you'll have the same visual weaknesses as a vertebrate. Form follows function.

What I was wondering was if the retina of the ceph reflects light like a tapetum lucidum?

In short, I think its all a matter of selective pressure on the eyes.

Sushi and Salmon Roe, and raspberry sake

John

"Pulling out jives and jamboree handouts, two turntables and a microphone..." - Beck

[Andy Lister]

I was going to say all that about the rods and cones lark! How rude!

Something did strike me though:


If you squint, you change your intake of focal light, and compress it to hit more on the colour receptors of the back of your eye...if you widen your eyes, you gain a better black/white/movement vision

Could an Octo do this too? Could they squint to alter their perception of things?

Anyway I am pretty badly scuppered when it comes to colour vision, red/green/brown... blue/purple

Not too good eh. Out of that CB page I could only see the first one and in the last couldn't make out jack. I think I might add a few more arms to me and become an octo... they have it easy!

But yeah, they shouldn't need colour vision, if you do only see in shades of grey then you could just belnd to the same shade... clever eh!

~Andy

[Fujisawas Sake]

Andy,

Actually, the ceph eye moves its lens in and out from the retina, by way of ciliary muscle action. Its like the lens on an SLR camera. This is a magnificient design.

Yet another sidenote in the natural history of the cephalopod eye: Our eyes use a strange system of processing, whereas rods and cones point backward to catch reflecting light. Ceph eyes dierctly catch the light by pointing forwards. And the reason I find this interesting is that the eyes develop within invaginations (in-pockets of the skin) similar to the pigment-cup ocelli of flatworms and such. Vertebrate eyes have developed as a part of the brain. Its also believed that they see polarized light, so color perception isn't quiet as important as light perception.

Yeah, they are a magnificent design.

John

[Jean]

What I know is that the *^%#^&#^ so and so's can adjust for refraction at the water's surface! I managed to annoy Delphine this morning and from under the water I got doused .......Her aim was spot on too!

J

[johfro]

Thank you all for your answers!

/johfro

[Infusoria]

I've looked at that picture for ages and I can make out a sailboat.