A bit of info on eyesight please?

[wadih]

After reading the cooked eggs thread, I selected 5 adult snakes (garter: 2 males and 1 female. Natrix: 1 Male and 1 female) and separated each one of them in different aquariums. I brought quail eggs broke one and painted the rest with its white to enhance the smell.
Nothing happened and they even did not consider it as food, one of them started playing with the egg as a ball

Any way, I tried another test: I kept the temperature of the room where the snakes are to 15C (57F-60F) which is the lowest degree (as I read) for this type of snake to be able to hunt. I brought several colored and transparent small plastic bowls and put small fish in each one of them, the bowls were high enough for the snake to see the fish through the plastic. And since the temp was low they are not interested in putting the effort except if they were sure it is worth it.
The important thing was that they were able to detect the movement inside the bowl regardless of the color (I even tried dark blue); however, none of them were able to detect the movement in the water with similar bowl-fish color test (in light or dark orange / red / brown) at all.
I am not sure if that can tell something or not ( I guess a forum moderator can give us final decision) but I think the snakes are not able to differentiate the color as much as human. They only tell the difference if it was big; otherwise, they will never tell if there was a fish or not.

I will be glad to hear more opinions about this...

[Charis]

I haven't really noticed whether mine have any preference for colors, will have to watch for that. I have noticed that both of mine, to begin with, hunts more by motion, after they have eaten 1 or 2 fish, they get more into a frenzy & seem to hunt more by touch. Neither of them seem to use their eyes much.

[guidofatherof5]

I once asked if garters can see color. I will they to find that thread and post a link. If I remember correctly they may be able to see limited color.

[aSnakeLovinBabe]

well, I don't know how much color they can or can not see, but even if they could not see any color at all, if you put an object on a background that is similar in color it is naturally going to be harder to distinguish because the shades themselves are similar.

[Lovok]

I did a search for "eye sight" and "vision", but didn't really come up with anything helpful. I'm reading conflicting info though, here and in some reference books.
Some stuff I've read says eastern garters have "excellent eyesight" and use it for hunting, while some people here have said their vision is no better (if not a little worse) than our own. In my/our case, when I know Scylla is awake, she doesn't always react to me, my hand, or my movements, at least up close. If I'm a few feet away from the tank, she'll duck for cover into a hide when I move closer. Yet when she's on her branches and I do the same thing, she couldn't seem to care a less. This leads me to think that they can't see well, and are "movement" based. but even that doesn't apply to her half the time. When I drop a worm into the tank, sometimes it barely hits the floor and she's on it (it never has a chance to move). Other times, she flicks & searches, and seems to have trouble finding a morsel, even if it's right under her tongue.

So, is their eyesight bad or not? If so, are they far-sighted (can see stuff better when it's farther away) or near-sighted? How dependent are they on movement vs smell vs sight? Does my girl need teeny specs on her snoot like the Incredible Mr. Limpett?

[guidofatherof5]

I think what you are seeing is selective vision. I think Scylla is reacting to what she wants to and when she wants to. I have had big radix females catch pinkies I've thrown towards them. I think garters have great vision all the way around.

[Lovok]

You know, I considered "selective vision", but didn't really think they could do that. I think I'm finding it hard to read her because I just can't tell what she's looking at and when. That "no blinking" somewhat expressionless thing snakes have going is NO road map to their thoughts! LOL

They must take in everything and evaluate it, because she rarely turns her head like she's zeroing in on something.

[wadih]

When I did the test i mentioned earlier I was not checking their eye sight at all. I tried once the same experience guidofatherof5 talked about (throwing the fish) and it worked perfectly specially if the snake is excited about food (usually happens after the first fish). In fact I think they have perfect eye sight.
However, the test was to know how good they differentiate colors. And what I reached was that they do not differ colors a lot. I mean they see for example orange, dark yellow and red as the same color and so on.
But I am not sure if these results can be generalized on all thamnophis, and that is why I asked if someone got more info about it.

[Lovok]

When I did the test i mentioned earlier I was not checking their eye sight at all. I tried once the same experience guidofatherof5 talked about (throwing the fish) and it worked perfectly specially if the snake is excited about food (usually happens after the first fish). In fact I think they have perfect eye sight.
However, the test was to know how good they differentiate colors. And what I reached was that they do not differ colors a lot. I mean they see for example orange, dark yellow and red as the same color and so on.
But I am not sure if these results can be generalized on all thamnophis, and that is why I asked if someone got more info about it.

Your thread about whether they see colors or not was what prompted me to finally ask my question, even though I've been thinking about it some time beforehand. Sounds to me like they have some definite kind of color-blindness. I guess questions like ours would be better answered by someone who's got some herpetophysiology--yeah, I just made that word up--knowledge, and know how their eyes are actually structured (rods? cones? both? more of one than the other?).

[guidofatherof5]

I know that someone from the forum put a link to a study for this color question. I looked in my records and couldn't find it. I'll keep looking.