Octopus Field of Vision

[Nancy]

Hi all,

I'm very interested in finding out how octopuses see - specifically, what is their field of vision. From what I've read, I'd think they would see well. I understand that each eye operates independently, but that they can swivel both eyes forward and look at you (and I've certainly seen many demonstrations of the octi stare).

I encounter this issue of vision in direct ways every day, as I drop small crabs in for my bimac to catch. I am amazed at instances where I'm sure he will see the crab, but he can't. Yet other times he sees very well. Watching him hunt, I think he depends at least as much on feel as on vision. By feel, I mean feeling with the tips of his arms. I've noticed I can drop a fiddler crab right on Ollie's head, and he never notices it (until it falls off, that is!).

Anyone have any information about this, or can point me to some?
Thanks,

Nancy

 

[o.vulgaris]

About 4 year's ago I saw a documentary on the Discovery Channel specifically about octo's, they explained the condition's of their vision, they showed that they could actually see the difference from pink to light blue rocks, it was very cool, they also had a mimic octo which they showed that he/she could change it's form and texture by blending in with the background, I don't recall the title of the documentary, I'm sure someone has seen it.

 

[Melissa]

The documentary might have been "Incredible Suckers." One segment definitely features fabulous octopus camouflage.

Melissa

 

[perke]

A reference by a guy called Bernd Budelmann may do the trick its in marine fresh water behaviour and physiology vol 27 (2-3)pp59-75

It's a bit heavy on the biology so you may need to sit with a science dictionary. But its pretty interesting it goes over polarised vision, structure of the eye, eye movements e.t.c

It goes on to say that possibly an octopuses vision may not be as important as a squid or cuttlefish due to the optic lobes being smaller. I hope this helps some

 

[o.vulgaris]

The documentary might have been "Incredible Suckers." One segment definitely features fabulous octopus camouflage.

nope, it's not that one, it's another one. I can't believe I don't remmeber the title, if it wasn't formy bad memory,hehe.

 

[Armstrong]

Re: Octopus Field of Vision

Hi all,

I'm very interested in finding out how octopuses see - specifically, what is their field of vision. From what I've read, I'd think they would see well. I understand that each eye operates independently, but that they can swivel both eyes forward and look at you (and I've certainly seen many demonstrations of the octi stare).

I encounter this issue of vision in direct ways every day, as I drop small crabs in for my bimac to catch. I am amazed at instances where I'm sure he will see the crab, but he can't. Yet other times he sees very well. Watching him hunt, I think he depends at least as much on feel as on vision. By feel, I mean feeling with the tips of his arms. I've noticed I can drop a fiddler crab right on Ollie's head, and he never notices it (until it falls off, that is!).

Anyone have any information about this, or can point me to some?
Thanks,

Nancy

Hey, Octopuses see Black, white, and shades of gray.
What's VERY interesting about them is the fact that they can change color even if there eyes can see only black and white.
So how do they change the color of there skin to match the different colors near them if they only see black and white?
Well that's simple.
For example, Let's say there was a peice of red coral near the octopus.
To US, the coral is RED, but to the octopus the coral may be a dark gray.
Almost black. So what the octopus does is change the color of it's skin to DARK GRAY. The octopus THINKS it's changing it's skin to dark gray, but it's really chaning it's skin to red.
But as he sees it he sees that he's changing color differently. Extremely hard 2 explain, but im sure you'll understand.

Also, when an octopus sees the colors: Green, and white, WE see it as green and white. THEY SEE IT as BOTH white. weird. lol

 

[Spoony]

how do they camoflauge themselves against green and white then if green is the same as white and vice versa?

 

[Nancy]

I think that there's a bit more to this color theory than is immediately obvious. If you study color theory, you'll find that any color can be reduced to a shade of gray, but different colors can be the same shade of gray, have the same "value". So it has to be more than just distinguishing shades of gray. How does an octopus choose to be red purple and not blue purple, to match the coralline algae?

Seems that I read about a study (forgotten who or where) that showed that octopuses can distinguish between red and green.

I'm sure more interesting studies will come to light.

Nancy

 

[um...]

How prevalent is colour vision among octopuses' predators and prey? More specifically, how good is their red sensitivity? I would expect that diurnal animals that live in shallow water would benefit from having colour vision, but this doesn't seem to be the case with most cephalopods. Obviously, their lack of colour vision and the restriction of chromatophore colours to black, brown, red, orange, or yellow hasn't hurt them very much. However, Watasenia scintillans seems to have colour vision, so I've got to wonder why it isn't more common in cephs.

 

[joel_ang]

Well yea, they say that Watasenia scintillans otherwise known as the firefly squid are the only cephlapods with colour vision, so far...

Cuttles and octos will usually notice moving things very quickly, so maybe this helps them to catch prey. And they also have taste receptors in their suckers so maybe this could help close in but not find prey.