how good is tarantula eyesight?

[tim battman]

just wondering if anyone has any idea as I've noticed that some of my spiders almost seem to blunder into the cickets while others like my N.chromatus for example will rush from on end of the tank to the other and nail the cricket do some have more developed ocular capabilities or am i just imagining it?

[Thomas Pitchford]

In the world of true spiders there are clearly superior forms of sight, notably the jumping spiders. Most T's are so opportunistic that sight does almost seem unimportant. And even though chemicals and vibrations are important in mating (drumming and can you use the word "pheremones" when talking about spiders), T's do appear to be aware when an potential mate or intruder is present. Though I'm sure someone has read some proper research and will point you in the right direction, I wonder if it wouldn't be interesting for members to compare some species (but as mentioned several times here, T's do seem to range in abilities, behaviour and even personality within a species, much less between differing ones):

Our biggest gal, Lasiodora parahybana, definitely goes by other senses other than sight - I've placed things right next to her with no reaction - but once something messes with her tripwires that are all over the place, she's on to it.

Our Acanthoscurria geniculata is a little cheetah, running down locusts the moment she's aware of them, but I think she just "feels" the movement. There's hardly any webbing in her tank and yet she has turned around many times to "acknowledge" my presence (a waving pipe cleaner or encroaching cardboard divider).

I think our Grammastola rosea is dyslexic - she can sense the little locusts and crickets bounce around in her tank immediately, trace them into a corner and then she jumps left if it's on the right side or her and jumps right when it's on the left. Kinda funny, kinda sad, but being teachers we love our little "special needs" girl all the same. And she always does get it eventually!

The impressive one for us, as you have described with your example, is our avicularia. She spends most of her time (naturally) on top of one of her sticks in an old sweets jar. But the moment something hits the bottom of her tank, she's stalking it and runs it down. So may there be some advance eyesight to aboreal species? They do have bigger pads on their feet as well, so perhaps more sensory feelers? I don't know, but it is amazing to watch.

I remember there being some really interesting passages in Foelix "Biology of Spiders", but nothing I can quote from memory (a bit "special needs" myself I sometimes think) so when I get home today if I re-read something particularly good about eyes and T's I'll post it later.

[Maria Clarke]

great information thankyou,
it does seem to me that each T has its own way of catching its prey,
I have a very lazy rosie that refuses to move off its clay pot till the cricket comes to him, but my cambridgei is stalking as soon as his lid is moved,

they are all different and special in thier own way

[James Box]

well, the eyes must be for "something"...they all point in different directions, for example...
so i am not convinced it's all just for picking up differences in light and dark. however, sometimes the behaviour seems to indicate that they are using their keen ability to feel vibrations and air changes, as well as vibrations on their silk as pointed out above.

i have a similar experience with my versicolor. about a week ago, i was tending to it, and it decided it wanted to come out, and basically be a brat, running all over me. it also jumped at me, clearly gauging the distance, and landing perfectly. i was thinking before that Avicularinae jump and "hope for the best," but now i personally feel that they can jump pretty good distances with all confidence they know where they're going. this to me argues for pretty decent sight.
it may be likely that arboreal tarantulas need better sight, and therefore have better sight, compared to terrestrials.
however terrestrials come out at night more often than not, so perhaps their vision is a bit better in darkness...

at any rate, it's a strange feeling now...if i have the lid off a tub containing a Selenocosmia, when it sits still, i wonder if it can see me, if it is hoping i don't notice it because it's sitting so still...or if like i previously believed, it's just sitting there oblivious.
the idea of them watching me adds an interesting thrill to the whole experience of feeding them, though!

[Phil Rea]

This post and this one may be of interest

Their eyesight is pretty poor really, but as James suggests, it appears that they can do more than differentiate between light and dark.

[Thomas Pitchford]

Thanks for that Phil. Do ANY spiders "see" in ultraviolet?? Andrew Parker's "Seven Deadly Colours" mentions a particular spider not being able to see in uv, but its webbing having uv qualities. So what about colouring on T's, especially cobalts, ornamentals and the like? What does a T looking a one of those T's see??

And yes James, I should have thought about avicularae jumping!! I'm blessed to catch it sometimes, but most of the time I know she's up on the lid and then I hear a "thwack" and there she is spread eagle on the side! The only thing missing is a little cry of "ta-daa!" I had put some of that down to her exploring and knowing her surroundings, but you're right, they can't "know" everything, especially in the wild.

[Phil Rea]

Jumping spiders (Salticidae) use ultraviolet cues for mating if I remember correctly. I seem to remember reading something about it a while ago.

[tim battman]

thanks everyone very intresting reading

[Stewart Shaw]

Thought I'd share something with you guys. Yesterday I received a juvie H. maculata around 2.5". Once released from her shipping container she started roaming about her new enclosure and came to a stop at the rim. Thinking it was a good kodak moment I went for my camera which was a few feet away. I turned around after retrieving the camera in time to see her jump onto the top of a nearby tank. That tank was about 4-5 inches away. It seemed to me she was able to judge the distance. She wan't being chased as I was not anywhere near her so it wan't like a desperate leap to get away. If anyone has other theories, I'd like to hear them.

[Thomas Pitchford]

That leads me to another question - has anyone ever had a T startled or bothered by a flash during a portrait session? I always hesitated using one at first (and still try not to if I don't feel it's necessary) but mine have never reacted. Do their eyes not respond to that type of light?

I did delve back into the several pages on neurobiology in Foelix "Biology of Spiders" - when you get to the section on eyes, he does spend most of the time on jumping spiders, which is understandable. However, just the fact that he talks about hairs, small slits all over the body and chemical receptors before even mentioning eyes kind of makes a point in itself.

But yes, they have to be able to "see" better than we think, and I do think they are much more aware of us than we let ourselves believe.

[mary walters]

They must see something. I was feeding my juves the other day and a 3 inch para jumped from one end of it's cricket box home to the other and grabbed a cricket out of the tweezers I was holding, scared me it did. Yes it's rapidly outgrowing it's home, repot soon.

[James Box]

thanks for posting that information, Phil!

just last night i had an interesting experience.
i was feeding a 1 inch Phormictopus atrichromatus that is housed in a cricket tub. i had the cricket by the leg with my tweezers and was just lowering it to feed when i dropped it, and it landed next to the tub. i think with all the movement i was making, it's unlikely that made enough of a disturbance in the air to let the spider know there was prey nearby, albeit just on the outside of the tub. as the cricket dropped, however, the spider noticeably hopped forward toward the cricket, but obviously couldn't get it...i thought that was odd, if it couldn't see well, as the cricket was about to land on the other side of the platic!

[chris carter]

Tarantula senses

Hi All

I have been reading these articles with interest eyesight is only one of many senses that make these creatures so unique.

They have poor eyesight, thier main purpose is to differentiate between light and dark, though it is possible that they may be able to make out crude images of objects within touching distance.

Tarantulas do not have a sese of hearing, but by using sensitive hairs all over their body they can detect the slightest vibrations in thier immediate enviroment.These hairs are connected to nerve endings which connect to the Ganglia which serves as a brain in Tarantulas. It only takes 2 or 3 of these hairs to move to get a response out of the tarantula.

The hairs on the legs are sensitive to air movements ranging from an insects wings to a birds wings. The degree of movement in the air is translated into whether the creator is small enough to eat or large enough to be a threat.

Sensory receptors in the exoskeleton and legs enable the Tarantula to control the position of its body and legs, they tell it where each is in relation to the ground, a potential prey or an opponent.

Instead of a sense of taste the hairs of the palps have chemical receptors, via these dangerous or unpalitable food can be rejected.
The mouth contains hairs that act as sensors and filters for the rejection of unwanted liquids and debris.

All these senses work together to give the Tarantula a complete mental image and mastery of thier enviroment.

Chris