Some spiders, such as cross spiders that are very common in the Netherlands, have poor eyesight. They primarily use their webs to monitor their surroundings. The majority of spiders have 4 pairs, and therefore, eight eyes. Each pair of eyes is specialized. The two large eyes at the front are mainly for focusing on their prey. The pair of eyes on both sides next to the large eyes are meant for estimating distances, which is especially important when pouncing on prey. At the back of their head, spiders have a pair of small eyes that enable them to see in the dark. Additionally, on both sides of their head, spiders have eyes that provide a wide-angle view. With these, they can keep an eye on their entire environment and quickly detect any moving prey. Spiders do not have antennae like insects, but in addition to their eyes, they have palps with which they can explore their surroundings.

The photo accompanying this article was taken by Thomas Shahan via flickr.com