Spiders are invertebrates but are not considered insects because they only have two main body parts instead of three, eight legs instead of six and no antennae. Most spiders also have eight simple eyes, while insects have large, compound eyes. There are so many different spider species found in Southern California. Most of them are venomous and will seek insects or other spiders to feed on. Although most spiders are venomous, most of them are still not dangerous to people. They may however attack when threatened. The 5 most common Spider found in Southern California is the; Black Widow, Brown Recluse, (both of which can be very dangerous to humans) California Trap Door Spider, Long Legged Sac Spider, and the Yellow Sac Spider.