Some potential insight into chameleon eyes, brains and "handedness"

[Seeco]

If this leads to your PhD please give me some credit...

I have a chameleon with his right eye scarred over and left eye fine. He has been this way for over a year and is healthy. The funny thing is that despite his right eye being blind he still favors the right side of his body. So he leads with his right hand but all he can really see to the right is what his LEFT eye can catch over his nose. The result is often him going in circles. For example, at his best, the way he climbs up a ficus is to corkscrew up in clockwise spirals. Also whenever he tries to mate he always crawls too far over the female and winds up past her and she "disappears" in his blind spot and he forgets but she is sitting right there like "come on"!

I think this accidental experiment sheds some insight on to what chameleons really see -- my idea now is that they do not actively process 2 different images from each eyes but rather favor one particular eye and the other is just on standby until it perceives some movement or something important. In other words, the MIND is in just one eye until they are both brought together like they do before shooting prey.

This case also suggest that chameleons favor one side of their bodies like how humans are right or left handed.

I know one example is not sufficient to conclude anything but it would surely make a good lab experiment for someone to do -- just make sure you cover the eyes and don't poke them out or I will find you!

 

[ataraxia]

https://www.chameleonforums.com/can-they-really-watch-two-things-same-74871/

I think we are on to something

 

[kinyonga]

When they show defensive posture with the hand raised up close to the chin which hand do they raise?? Is it always the same one? Do they show handedness?

One panther chameleon I had developed cancer in the eye and the eye was removed. He did circle for a day or two but then he was fine...and he also learned to shoot his tongue out (about 80% accurate) in spite of having only one eye.

I'm looking for more information I had on both handedness and the eyes...hope I can find it.

 

[Captive Creations]

I have a veiled that is blind in his right eye. is there anyway I can add to this. Hes my baby so i spend a lot of time watching him and caring for him. He was a little unbalanced looking right after loosing this eye, but has since adjusted nicely. and now shoots with about 80-90 % accuracy. He favors his left side and always leads with the left hand. when he is defensive (which isn't often) he holds his left hand up.

 

[Seeco]

I have a veiled that is blind in his right eye. is there anyway I can add to this. Hes my baby so i spend a lot of time watching him and caring for him. He was a little unbalanced looking right after loosing this eye, but has since adjusted nicely. and now shoots with about 80-90 % accuracy. He favors his left side and always leads with the left hand. when he is defensive (which isn't often) he holds his left hand up.

See that makes "sense"! The fact that my guy does the opposite makes me think that he is a righty by habit and will always favor that side thus "proving" handedness.

 

[Seeco]

https://www.chameleonforums.com/can-they-really-watch-two-things-same-74871/

I think we are on to something

Since i was pretty young. Seeing my first chameleon i was fascinated by the eyes and how they move. When observing them, i wondered can they really see out of both eyes at the same time and follow?

I have read pieces saying that they indeed can see two different object at the same time. Im not sure if i completely believe this....Not talking about tracking objects with each eye as i know they can do this...Im talking about following with each eye a independent object and fluidly watch each movement.

1) From watching them a LOT and with handling tricks. I have noticed that they literally focus one eye at a time. Kinda like having two cameras switching from one to the next very fast or as needed. The reason i have come to this conclusion is when i have a chameleon that is thirsty for some human blood. I will distract with one hand and with my other hand i can literally touch anywhere i please on the other side of the chameleon. This is done with the one eye focusing on me and facing the side of the chameleon. As long as i keep them busy and they cant see movement from me on the side im facing..they will not switch away..

2) This is basically the same as above with the exception that quite possibly every single time i do this. Just maybe, im out of peripheral vision of the other eye. It is possible as i cant normally see exactly where the other eye is facing but i have literally touched all over the head, casque, arms, body, etc..(except the eye) with them showing no clue im there.

Another side to my first hypothesis...Maybe they are so focused on me that they dont care of any other intruders.

Im still going with #1...What do you guys think?

Ya I think we are on the same page. Maybe there already is a study out there.

 

[kinyonga]

"Chameleons scan their environments by using saccadic (rapid, stop-go) movements of each eye independently. Only one eye at a time is in focus, however, alternating at 1 sec- intervals"..."apparently only one eye's image is processed at a time"...
http://books.google.ca/books?id=f7e...e&q=chameleons AND focussing AND eyes&f=false

"the crystalline lens of the chameleon has negative refractive power"...
http://www.ncbi.nlm.nih.gov/pubmed/7854450

"Chameleons seem almost as accurate measuring the distance with one eye as with two"...
http://books.google.ca/books?id=w6m...e&q=chameleons AND focussing AND eyes&f=false

More...
"These observations suggest the existence of two independent premotor neuronal circuits for left and right eye saccadic motor control in the chameleon"...
http://www.ncbi.nlm.nih.gov/pubmed/11497059

 

[Seeco]

That settles the vision thing!

How about handedness?

 

[Trace]

My deremensis put both hands up when they see me; does that mean they are ambidextrous?

 

[ataraxia]

"Chameleons scan their environments by using saccadic (rapid, stop-go) movements of each eye independently. Only one eye at a time is in focus, however, alternating at 1 sec- intervals"..."apparently only one eye's image is processed at a time"...
http://books.google.ca/books?id=f7e...e&q=chameleons AND focussing AND eyes&f=false

"the crystalline lens of the chameleon has negative refractive power"...
http://www.ncbi.nlm.nih.gov/pubmed/7854450

"Chameleons seem almost as accurate measuring the distance with one eye as with two"...
http://books.google.ca/books?id=w6m...e&q=chameleons AND focussing AND eyes&f=false

More...
"These observations suggest the existence of two independent premotor neuronal circuits for left and right eye saccadic motor control in the chameleon"...
http://www.ncbi.nlm.nih.gov/pubmed/11497059

Kinyonga to the rescue!!

 

[Trace]

Don’t most chameleons put the hand up that is closest to the perceived predator? i.e.. If I approach from their right then the right hand goes up. Most chameleons in captivity are in large fixed cages with fixed basking areas so their choice of ways or how to sit (sideways or back to owner) in that basking spot are limited to how the cage is furnished. Because the cage itself doesn’t move or rotate, the owner (predator) will always approach from the same side – the front – see the chameleon in it’s same normal basking position and thus will always see the same hand go up. Is it true ‘handedness’ or just cage limitation on threat posture we are seeing?

 

[Seeco]

Well that makes perfect sense but re-read what my guy with one eye does in the first post...

 

[jannb]

I have a panther with only one eye. When Jr was 4 months old his right eye ball had to be removed due to an eye injury. Jr is 3.4 years old now. I have been watching him carefully since I first read this thread. Jr has a large free range in my living room and gets around in it quite well. When I bring him in from outside he will use either of his front legs to reach for the branch on his FR. I've seen him use both. Also when I put up my hand up for him to crawl on, to take him outside he has used the right front leg and the left front about equal amount of times for his first step. Jr will wildly shoot at his food if you allow him but I just always hand feed him. He probably could cup feed but I've just always hand feed him. He's such a sweet boy and it's a pleasure to take care of him.

 

[Seeco]

Hmmm. My guy still has the damaged eyeball but it is completely glazed over with what looks like a huge cataract or grey film. He actually aims and shoots fine. And acts like he is focusing with both eyes. Maybe the eyeball still being there in his head is why he continues to use that side even though the result is he just gropes blindly and spins around.

 

[jannb]

Jr still has the eye socket just no eye ball. He will move that eye around almost like he's looking at me. It doesn't look bad at all. Allot of people see him and most doen't even notice that his eye ball is missing unless I point it out. Here's a picture of him and the missing eye ball.

 

[Seeco]

Hmm. There is no actual eyeball in there though? And he still tries to "look around" with it? What is in there that moves around? Just muscle?

A side note -- this discussion makes me think that it is worse / sadder for a chameleon to lose an eye than other reptiles...

 

[Thezillaman21]

When they show defensive posture with the hand raised up close to the chin which hand do they raise?? Is it always the same one? Do they show handedness?

One panther chameleon I had developed cancer in the eye and the eye was removed. He did circle for a day or two but then he was fine...and he also learned to shoot his tongue out (about 80% accurate) in spite of having only one eye.

I'm looking for more information I had on both handedness and the eyes...hope I can find it.

they\ always\ raise\ the\ one\ closest\ to\ what\ they\ feel\ threatened\ of...\ if\ my\ guy\ is\ head\ on\ he\ raises\ both....

 

[Motherlode Chameleon]

My Veiled Zeus got a cricket spur stuck in his eye while feeding when he was about a year old. He never could see out of that eye well however he still managed to climb and eat. It has been a while since I had him and wish I could recall more. Even though he could not see out of that eye when ever he hunt his eye would act as though it where normal except he would miss occasionally.

 

[Seeco]

My Veiled Zeus got a cricket spur stuck in his eye while feeding when he was about a year old. He never could see out of that eye well however he still managed to climb and eat. It has been a while since I had him and wish I could recall more. Even though he could not see out of that eye when ever he hunt his eye would act as though it where normal except he would miss occasionally.

The guy I had with one eye really never missed but like I said there was still something of an eyeball in there. Vet said it was useless though.

 

[phylicia]

Handedness

My Cham Rango Nosey be reaches for me with both his hands arms wide out like he wants to hug me..He does this action when he is insistant on going on my head..Fact..LOL