Jumping spiders are active hunters, like tiny lions chasing down their prey (bugs). They usually have eight eyes: two very large front eyes to get a clear, colour image and judge distance, and extra side eyes to detect when something is moving.
Some spiders make nets to catch their prey. These net-casting spiders also need to see clearly and judge distances. Some have developed huge, scary-looking black eyes that stare straight ahead, so they are nicknamed ogre spiders! These gigantic eyes help the spider to see a wide area and accurately throw down its spider web net to catch its prey. Here’s a picture of a net-casting spider.
Some spiders live in caves that are completely dark, where eyes are no use at all. They have to rely on other senses to find their food in the dark. To save energy making eyes, these spiders lost their eyes during evolution, so now some of them have no eyes at all.
Picture Credit : Google