Camouflage and the Cuttlefish!

[douglas emery]

hello to all of you cuttlefishers. i am a novice at the cuttlefish and am working with 4 of them for an upcoming project in texas. i am trying to put photographs in the bottom of tanks which the cephalopods will camouflage to. i've had some mixed information and was wondering if anybody would be able to email, chat, phone with me about this.

additionally i will be looking to find my 4 cuttles a new home in a few months and would like to find a happy one. please let me know if anybody could help me out.

thanks!

 

[robyn]

Hi Douglas,

Have you spoken already with Roger Hanlon at the MBL in Woods Hole? His lab does a lot of work that sounds as though it might be quite in line with what you're trying to do. Is there some specific questions you're grappling with? Maybe people here have cuttlefish in home aquaria and/or work with them for behavioural studies. Can you add some details about what you're hoping to test?

Good luck with it!

 

[douglas emery]

thanks for the help

i have spoken to dr. hanlon. he was very helpful but is out of the office (i'm sure diving or doing something fun) right now and i'm up against a sort of deadline. i'm not really testing anything as much as showing what amazing things cuttlefish can do. i want to make large photos for the bottom of the tank, but was told that the colorful patterns i had wouldn't work. i didn't really understand why and was hoping to have somebody explain the color range and pattern restrictions of the cuttle.

i have read up on the 3 types of camo which dr. hanlon has worked on, but as he's away i was hoping to get some more explanation.

thanks for any help!

 

[robyn]

Well I think the idea is that they have three main types of camo patterns (uniform, mottle and disruptive) and can really only produce variation on the three (and therefore not actually match any possible substrate - from memory I think Roger tested them with a blue/yellow check pattern and they could not match it, not being able to make either colour well).

If you are using bright colours you also have to work from the idea that since they are colourblind they will use the contrast and polarisation of light to match, not the colours themselves. For example, two colours (red and blue, for example) of equal intensity will most probably be perceived as a uniform background since its not the hue but the contrast between them that the animal is seeing. When you combine this with the fixed three types of camouflage they can produce (in shades of brown/grey/black/white), using very brightly coloured backgrounds might now show their skills to their best advantage. Perhaps what you could try is using your bright backgrounds and also making black and white copies of them to see if the camouflage is better on one or the other, or try more naturalistic backgrounds (natural aquarium gravel or a rocky- or sandy-bottom picture).

You might also look at the degree of 'bumpiness' the animals make on their skin (the little papillae are also used in camouflage) when faced with different backgrounds?

Maybe some more people with technical knowledge of ceph vision can weigh in here too. I've been lucky to work with Roger in his lab but not on this specific area, and my memory is not the best either...

 

[monty]

to TONMO!

I've only got a few minutes just now, but some quick thoughts/questions/facts:

1) The book by Hanlon & Messenger (I think it's called Cephalopod Behavior) is a good reference for this sort of thing
2) as far as finding a home, what species are they?
3) here's my understanding of meaningful factors:

* most cephalopods, including all cuttlefish, are believed to not see color
* experiments have shown that the active mechanisms for patterns are driven by perceived intensity in black-and-white
* cuttlefish can see the polarization direction of light, which humans can't. They can also change the polarization of their body patterns. Whether they use either of these for camouflage or not I don't know, but if, for example, you use LCD monitors to show your pictures, they will have a polarization factor that will look strange to cuttles even though they look normal to humans.
* there has been a lot of work done on the patterns of cuttles. Hanlon's recent work on there being a limited repertoire is one. I don't have time to look it up, but look at Hanlon's paper's bibliographies, do google scholar searches, etc, and you can turn up a lot. Moynehan (possibly misspelled) did a lot in sepioteuthis.

That's my brain dump. Hope it helps a bit.

 

[douglas emery]

that was a lot of information. thank you so much for the explanation. i have seen pictures of them changing to be colorful in nature. i know there are misrepresentations online.... does this mean they do not change to colors at all beyond black, white, grey and brown? i understand the color blind and polarization issues. i was intending to use some black and white, but was under the impression that they were not big fans of black and white. i was told they react better to grey and other colors. (this may have been wrong and would clear up a lot if it was).

unfortunately due to the fact that this is a photography endeavor i do not think i will be able to include texture. however, do you think if i had a flat picture of sand or coral (just examples) that it would camouflage to the flat surface?

i want this to be beautiful and show the cuttlefish in the best light. i do not want them to be unhappy or not to do the camo as they can do so well only because i didn't know better.

 

[robyn]

Well, the colour range is a bit species-dependent too - the flamboyant cuttles are really spectacularly coloured, but I think officinalis (is this what you're working with??) either make the zebra striped pattern, (which is a social behaviour and not camouflage, as I understand it), or they make variations on a brown/white spectrum. Somebody can no doubt explain more about the specific pigments in the chromatophores, I don't want to tell you something wrong because I don't know enough about them.

As for them being not big fans of black and white - I'm not sure. Roger's lab uses many variations of a high-contrast black-white check to test their animals (there are photos in many of their papers). While its not a 'natural' background per se, it is a very useful experimental paradigm because of it simplicity. They also use flat photographs of gravel, I think, so I imagine if you use flat photos of coral or sand or whatever, as long as the animal can see it they will try to match it. Just because its not actual coral or actual gravel doesn't mean the animal won't camouflage to it, but it does limit your ability to extrapolate to what a 'natural' response might be to the real thing. It sounds as though that's not your main goal so I see no reason why photos won't work for you.

On the technical aspects, provide good light from the side so the bottom surface is not reflecting the light source and the animal cant see the photo, and you might need to play around a bit with lighting angles and stuff to get the animals to be really showing their stuff.

Do you have some experience working with animal behaviour? If not, maybe do some reading about acclimation times and handling techniques to make sure the animals are able to work their best for you.

 

[douglas emery]

i will be reading posts and information all night i imagine. i'm wondering if i can do gray scale versions of the patterns i already had. i'm still trying to figure this out with my new found tonmo provided knowledge.

i will most likely be posting new smaller questions soon. i do not actually have a confirmation on the species... but they are going to be about 6-8" so i assume they are not the sepia bandensis.

thanks again for all of the advice. i'll be back for more soon!

 

[monty]

I don't know about the specific pigments per species, but the usual rule (and I think this applies to officinalis, at least) is that there are three layers of chromatophores and then leucophores underneath. The leucophores reflect white light, and are the blank canvas, but tends to pick up the colors in the environment. The 3 layers of chromatophores go from light yellow-brown at the deepest layer, to medium rusty brown in the middle layer, to black at the top (note: I may have the layers backwards.) So the displays have things that contribute to color: the yellows and browns of the chromatophores and the color reflection of the leucophores. There are also iridophores which provide reflection of iridescence and polarization, and probably have some effect on color as well.

The main point to remember is that the cuttlefish don't see color, so their matching of colors in the environment is passive, so that in their normal settings, their responses on seeing a black-and-white pattern will make a pattern, partially colored, that looks cryptic to animals like us that have color vision. But the cuttles don't see it. Similarly, with flamboyant cuttles and blue-ringed octos, they have dramatic color displays to warn off enemies that they're toxic, but they can't see the colors.

In think the take-home lesson for cuttles is that they don't see color, but between seeing shades of grey and using the built-in palette of their chromatophores, and the environmental colors reflected by leucophores and iridophores, they are able to produce displays that are colorful to those of us who can see color, as well as matching their environment for effective camouflage against animals who can see color.

 

[cuttlegirl]

Are you photographing each of these animals alone? They will react to another cuttlefish in the tank with them, so that may change their coloration against the bottom. Have you thought about putting the background you want against the side of the tank instead of the bottom?