Why Do Spiders Have 8 Eyes?


Why Do Spiders Have 8 Eyes? Most spiders have eight eyes, which tend to be arranged into two rows of four on the head.

These eyes are categorized by their location and described as anterior median eyes (AME) or anterior lateral eyes (ALE). And then posterior median eyes (PME), and posterior lateral eyes (PLE).

This is an adaptation that has evolved over time to help spiders survive and thrive in their environments. However, have you ever wondered “why” spiders have so many eyes? And more importantly, what purpose do they serve?

Well, in this blog post, we’ll uncover the truths behind spiders’ mysterious anatomy: discussing both the evolutionary reason for their additional pairs of eyes as well as some key facts about how spider vision works.

Why Do Spiders Have 8 Eyes?

So why do spiders need so many eyes? Well, it turns out that each pair of eyes serves a different purpose. The larger, front-facing pair of eyes, called the principal eyes, are used for detecting motion, while others are used for seeing in low-light conditions.

All eight eyes work together to give the spider a near 360-degree view of its surroundings, making it easier for them to hunt down their prey.

By having multiple sets of eyes, spiders are able to gather a more comprehensive understanding of their surroundings, giving them a distinct advantage in hunting prey and evading predators.

Can Spiders See Through All 8 Eyes?

With so many eyes, you’re probably wondering if they can see through all of them at once. The answer is yes! but not in the way that you may think! Each of the spider’s eight eyes has a unique function and not all of them are used for clear vision.

For example, most spiders have two large front eyes, called the anterior median eyes (AME), which are used for high-resolution vision.

The other six eyes are anterior lateral eyes (ALE) posterior median eyes (PME), and posterior lateral eyes (PLE) which are typically smaller. These eyes are used to detect motion and are more sensitive to light than the AME.

Do All Spider Species Have 8 Eyes?

One common misconception is that all spiders have eight eyes. While it’s true that many spider species have eight eyes, not all do. Some spiders have only six, four, or even two eyes.

But, despite the variation in the number of eyes, spiders are still highly skilled hunters, using their sense of touch and other senses to navigate and catch prey.

Types Of Spiders That Have 8 Eyes

So we know not all spider species have eight eyes! However, there are still several species of spiders that have eight eyes including Net-casting spiders (Deinopidae). Here a just a few of the most common spider species that have eight eyes:

  • Wolf Spiders
  • Fishing Spiders
  • Jumping Spiders
  • Black Widows

Despite the extra set of eyes, these spiders still primarily rely on their sense of touch and vibration to navigate their environment and hunt for prey.

Can Spiders Still Function If They Lose An Eye?

Yes, spiders can still function if they lose an eye. Spiders have multiple sets of eyes that serve different purposes and they use these eyes differently than humans do.

For example, some spiders have fewer or even no eyes but are still able to hunt and stalk prey, as they have other adaptations to find food.

In certain spider groups, there has been a loss of eye pairs over evolutionary time, including the loss of principal eyes in some species. Despite this, these spiders are still able to survive and carry out necessary functions.

Interestingly, studies have found that the size and position of eyes are key variable traits in spiders, with different families exhibiting extreme enlargement and even loss. Despite such variations, spiders remain effective hunters and survivors in their respective environments.

However, it’s important to note that the loss of eyesight can also be affected by factors like hunger. A study revealed that spiders can start to lose their eyesight if they get too hungry.


So now you know why spiders have eight eyes! If you found this article helpful don’t forget we have plenty more like this, simply navigate to our home page. There you can find a list of categories including different spider species.

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