Are tarantulas blind? We all know that most spiders have many eyes, way more than we do. But do these eyes help them see better, or are they blind? That’s a great question, and something I’d like to answer today.
I’m going to go over how many eyes the tarantula has, whether or not they have good eyesight, and I’ll also discuss whether there are any spiders that do have good eyesight.
The short answer to this question is this: Despite having many eyes, tarantulas do not have very good eyesight. They’re not blind, but they can not see very well. Rather than using their eyes to observe the world around them, they rely more on the many hairs they have on their body. These hairs pick up vibrations which let the tarantula know what’s happening around it.
How many eyes do tarantulas have?
The tarantula, just like most other spiders, has a total of 8 eyes. They have two bigger eyes in the center of their head that are each surrounded by three smaller eyes. Take a look at this image, it shows perfectly how many eyes the tarantula has and where they’re located:
As you can see in the image, 6 of the eyes are quite easily visible, but the other two (numbers 1 and 2 on the image) are a little bit harder to spot. They’re located slightly above and to the side of the center eye.
Can tarantulas see well with so many eyes?
You might think that with so many eyes the tarantula has exceptional eyesight, but this is not the case. They may have many eyes but their vision is quite poor. You might wonder then, why would they have so many eyes if they can’t see well, what’s the point?
There’s a great answer to this question I found on Reddit that I will quote:
Spiders and insects have hard, inflexible outsides, which means their eyes are too; us squishy mammals can make complex eyes, with a variety of muscles, to allow them to move around to see more than just directly in front of us — animals with exoskeletons don’t have that advantage — with some exceptions, like Preying Mantis, who can move their head to give them almost 360° vision (but mantises still have extra ‘eyes’ on the top of their head, too). So, when an animal with an exoskeleton needs a wider area of vision, their options are either way bigger eyes (like flies, dragonflies) or more eyes (spiders, other bugs). And, well, like everything involved in evolution, if it gets “just good enough”, it becomes a long-lasting trait. There’s no evolutionary push to change everything to make two complicated eyes when eight simpler eyes do fine for the spider’s survival.
So, to summarize, tarantulas have so many eyes because that’s how they evolved to have a wider field of view. Since having so many eyes does the job there’s no reason for evolution to change it. Don’t fix what isn’t broken!
D0 all spiders have such bad eyesight?
No! There are spiders, such as the jumping spiders, that have exceptional eyesight. They take maximum advantage of having 8 eyes and use them to the fullest. They need good eyesight because they use their vision to observe, track, and choose the most opportune moment to strike at their prey.
There’s a very interesting article about the vision of jumping spiders by the New York Times. It reveals the inner workings of the jumping spider’s exceptional eyesight which they discovered through the use of eye trackers. I highly recommend you check it out if you’re interested in the subject.
Do all spiders have 8 eyes?
The vast majority of spiders have eight eyes, but not all of them. There are no spiders that more than 8 eyes, but some do have fewer. For instance, the Symphytognathidae family of spiders has 4 eyes, the Caponiidae family has 2 eyes, and some other spiders, such as the Sinopoda scurion, have no eyes at all!
To learn more about spiders and their eye arrangements, there’s a great resource on BugGuide.
So, to sum it all up, tarantulas are not blind but they do not have very good vision. They have 8 eyes, but those 8 eyes do not help them see very well. There are spiders that use their large number of eyes to their advantage, such as the jumping spiders, but the tarantula is not one of them.
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