I’ve kept different tarantulas for more than twenty years. With some of them it’s obvious how many eyes they have, but with others it’s much harder to tell.
Also, it seems to be a really common question among owners. So what’s the answer? How many eyes do tarantulas have?
All tarantulas have eight eyes. There are eyes are in pairs, so they have four pairs of two eyes each.
That’s the quick answer! But tarantula eyes and their eyesight are wonderfully complicated subjects, and in this article I’m going to do a full deep-dive into everything you could possibly want to know in this area.
I will answer the question of not only the number of eyes they have, but also how their entire vision works. By the end of it all, you are going to have a much better idea of how your pet Tarantula is able to see and determine what is going on around them.
So let’s get stuck in…
Tarantulas Have Eight Eyes
First, let’s just clarify that your pet Tarantula is going to have eight eyes. That’s hardly a surprise at all, and you will also notice that their eyes are grouped together in pairs. That means they have four pairs, but they are perhaps not set out in the way you would expect.
As a quick side note, most people think that every spider in the world is going to have eight eyes. Well, while most of them do, that’s not always the case.
Instead, there are some that have only six eyes, and a few species with less. However, each Tarantula will have eight eyes of varying sizes.
The Distribution of Their Eyes
With a number of species of Tarantula, what you have is two large eyes in the middle of their head with smaller eyes grouped around them. Often, it will be three on either side, and that brings the total number of eyes up to eight.
To get a bit more technical, their eyes are located directly above the chelicerae. At least two of them are going to be pretty hard to miss with the size of them in relation to the rest of their head.
However, the exact location of their eyes does vary slightly between the various sub-species. With some, you do have one large main eye with two below and the smallest one above or to the side. At times, this smallest eye may even be difficult to spot, as it’s sort of hidden away, but it’s going to be there if you look hard enough.
Don’t Let the Number of Eyes Fool You
With eight eyes, you would be forgiven for thinking that a Tarantula would be able to see absolutely everything going on, but you would be wrong.
Instead, a Tarantula isn’t exactly blind, but it hardly has vision like an eagle. Instead, they are very restricted with what they can see. So, if you were of the opinion that they would have all-round vision, then that’s nowhere near the truth.
Perhaps we should say that if we had the same level of eyesight as a Tarantula, then we would be pretty upset.
So, if that’s not what happens, then how would you even describe the vision of a Tarantula? That’s what we are going to explore.
The Quality of Their Vision
What happens with a Tarantula is that it can only really see motion, light, and darkness. It struggles to make out anything else, and that’s why it ends up having to rely on other senses to get around safely. These other senses have been well honed over the years and generations.
But they do have one advantage.
With so many eyes, mixed in with their positioning, it does mean the spider has quite a wide field of vision. Do note that having a wider field of vision is different from a wider range, as wider range tends to focus more on the different things they can see rather than the area covered.
What we mean here is that they can cover a wider area with their eyes thanks to the positioning of them. In us humans, we need to turn our heads to see more to the side or up and down out with our field of vision. A Tarantula won’t have that same need to the same extent, and it’s all due to where their eyes are positioned on their head. [Source]
Also, their other senses being so heightened will also reduce the need for them to be able to see in the same way as we do. Basically, they have been able to learn to cope with having poor eyesight to such an extent that it doesn’t bother them in the slightest.
An Issue With Colors?
Aside from having quite poor vision, it seems that a Tarantula is also going to suffer from having some difficulty when it comes to various colors. As like many other spiders, it does seem that a Tarantula is going to be unable to see red.
This is all due to the light spectrum they are able to pick up on. It will fall short of the part where red kicks in, so they are then unable to see beyond this figure. This in itself is common. Different animals have varying abilities to see colors, but it just so happens that the Tarantula seems to fare worse than most in this department.
What this also means is that you can use this knowledge to your advantage.
Remember that your Tarantula is nocturnal. They will be far more active at night when it’s all dark. They feel more secure at these times, and that’s where you can get creative when it comes to being able to watch them go about their business.
One option is to get a red light. It will be dark enough in the room, if you use a red light as your only source, and as they cannot see red light, it will not spook your Tarantula into doing something different.
However, it will cast enough light on their home to allow you to observe what they are getting up to, and that’s quite a cool thing to be able to do.
How They Use Their Eyes
As your Tarantula has poor eyesight, then what will they tend to use their vision for? Well, the key is in the art of survival and their ability to differentiate between light and dark.
It seems that the Tarantula will use its ability to tell the difference between light and dark to help it in hiding. It is able to see this difference, to then help it with finding areas to potentially hide. It picks out the darker areas, senses the vibrations to come to some sort of conclusion as to whether or not it’s safe, and then moves there.
So, they use their eyes to guide them toward safety in this respect, and for a Tarantula that’s going to be a big thing. In other words, if your pet Tarantula is running away from you, it’s because they feel afraid, and they see a dark spot to aim for. They equate that dark spot with safety.
Their Circadian Rhythm
Another way in which the Tarantula uses their eyes is to help with their circadian rhythm. This is where they differentiate between night and day, and light levels have a lot to do with this, for obvious reasons.
They use their eyes, and their ability to see light and dark, to let them know when they should be hiding away in their lair, or when they should be out and about trying to either mate or catch some prey.
Their circadian rhythm is important for their survival. Their simple eyes just help them to understand what’s happening around them in this absolutely basic sense. However, without this ability, their life would become a whole lot harder, and their very survival would be in danger at various times.
But They Have So Many Eyes?
This is where it can get confusing for some people, as they simply see that a spider has all of those eyes, so why do they then have poor eyesight? Well, it’s all down to the way in which their eyes are actually made.
You see, the Tarantula actually has a hard, inflexible outer layer, and the same goes for their eyes. With us humans, our outer layer is soft, and the same applies to our eyes. It means we have a series of muscles that allow our eyes to work better than what happens with a Tarantula.
Instead, their exoskeleton means they cannot move their eyes around to see what is around them, unlike us. This immediately restricts what they will use their eyes for, but they have managed to learn how to cope with these restrictions over time.
So evolution has led to your spider having eight eyes, but here’s where another difference comes into play.
Human eyes are complex, and we have two. That’s because evolution has led us to this point where two complex eyes are best for our survival. In the case of a Tarantula, they have developed other heightened senses that help their survival, so the need for better eyesight is not something that is viewed as being a priority.
As a result, they may have more eyes than us, but they are simple eyes carrying out simple functions, and it’s all thanks to their general lack of needing anything else. Why waste energy on developing something that they don’t really need?
How a Tarantula Copes With Poor Vision
Now you know that a Tarantula has poor vision and can only see limited things. How do you think they then cope with not quite being blind, but not far off having no sight whatsoever?
The answer is in the other senses that they have, which go above and beyond normal levels.
With a Tarantula, what you get is a spider that has an amazing ability to sense things around them. Now, every spider is going to have this sort of ability, but the Tarantula has to be one of the best.
So, let’s look at the different senses that a Tarantula will rely on since it is unable to rely on its vision.
One of the main ways in which a Tarantula will ‘see’ is via picking up on vibrations. This is how the female will even be able to tell if a potential mate is nearby, never mind prey. [Source]
The way in which they pick up on these vibrations is pretty spectacular. They do so not only through their legs, but also through the hairs on their body. We are talking about something that is super sensitive to any movement, and when you consider how light some of their prey is going to be, then it lets you know how amazing this ability must be in a Tarantula.
It also explains why a Tarantula will move as slowly as it does at various times. They are moving slowly to be able to pick up on the vibrations as they go into a different area. If they moved quickly, then they would be masking any vibration with their own, and that’s not a good idea.
More on the Hairs
The hairs on the body of the Tarantula are pretty cool. Called trichobothria, what happens is that the sound vibrations change the air that then blows through the hairs. The Tarantula is so sensitive to what is going on that it realizes when something has changed.
This does mean a Tarantula can, in effect, hear or see what’s going on with prey that is a few feet away. That means they are far enough away to remain hidden until they are ready to strike, but close enough to tackle whatever is nearby before the possible prey is able to get away.
Those Vibrations are Everything
We are keeping on about the vibrations part due to its importance to the survival of the Tarantula.
Their ability to distinguish between vibrations is so good that they can tell what is making the vibrations in the first place. The female is going to quickly tell if it’s a mate, predator, or potential prey.
That ability is a wonderful way of showing how their senses are so finely tuned to their survival, as each aspect is covered in that alone. Their ability stops them from walking out into the trap of a predator, while also giving them the confidence to emerge from their layer because a possible meal is nearby.
That is really cool, and your pet Tarantula will still display those abilities even in their home. They will know when you have dropped some prey into their tank, and they will also know when you are nearby, so don’t be surprised if they hide away in the hope that you don’t see them. After all, they are only doing what comes naturally to them.
A Type of Sense of Smell
While a Tarantula does not have a sense of smell in the conventional way, they are able to differentiate between different scents or chemicals. They do this via those hairs on their body, and it just shows yet again how sensitive they are to what’s going on around them.
A Type of Hearing
A Tarantula has no ears, so it also cannot hear things in the way that we tend to imagine. Instead, they pick up on sound waves that brush past them, and it does involve those hairs once more.
You must remember that sound waves create those vibrations, so they won’t ‘hear’ some prey walking past. Instead, they will ‘feel’ the prey walking past, and that’s a different way of tackling things.
Evolution Won’t Let Them Lose Their Eyes
Considering the limited ways in which they use their eyes, it may be surprising to learn that there’s a general consensus that evolution is not going to let them lose their eyes entirely.
This is because they do still play an important role in their survival. Their use may be basic, but without their eyes, they would find life so much harder. For that very reason alone, evolution will more than likely stop where it is right now regarding the eyesight of a Tarantula. It works pretty well for them, so there’s no need for it to change at all.
So, to Recap
To recap, a Tarantula does have eight eyes, but they are very simple in what they offer to the Tarantula when it comes to vision. Don’t expect your Tarantula to even have any real interest in trying to see you, as they rely on other senses to get around their world.
Their other senses, including that ability to pick up on vibrations, has allowed them to survive for a long period of time in the world. They are heightened to such an extent that they do not even really require any vision to be able to hunt, avoid predators, and to attract a mate.
Your Tarantula won’t be able to see you coming, but they will certainly feel you coming, and that’s going to be good enough for them. They are excellent at sensing things to help their survival, as well as being able to thrive. They have been able to evolve over time into well-oiled machines.