As the name suggests, grass spiders spend a vast majority of their lives in grassy areas. They are able to weave funnel-shaped ground webs that then turn into living areas. Their webs are not sticky and are not used to capture prey, but rather to alert grass spiders of the presence of nearby animals. Once a prey steps on the web, the grass spider will quickly run across the web to hunt its prey. Grass spiders are generally harmless to humans because they possess little to no venom. Common species of grass spiders include the common grass spider, desert grass spider, common funnel weaver and the barn funnel weaver spider.
Orb weavers are the most common web-building spiders in America. This species of spider weaves the aerial, circular spider webs that are the trademark of spiders. Orb weavers catch their prey by building large silk webs. Unsuspecting prey blunder into the webs and are trapped. The weaver will then attack its prey with a venomous bite and wrap it up to be eaten. The physical characteristics of orb weavers vary; some are large and some are small. Weavers come in several shapes, sizes and colors and are only distinguished by their web-building characteristics. Orb weavers are not the only species of spiders to build webs; however, they are different in that they consume their webs at the end of the day to build a new one each night. Common orb weavers are the banded Argiope, tree spider, bolas spider, spotted orb weaver and Eustala.
Wolf spiders share several characteristics with their namesake the wolf. They are athletic, agile hunters. They possess keen eyesight and can usually chase their prey down over short distances. Different from the wolf, these spiders generally live and hunt alone. Wolf spiders make homes in diverse habitats including grasslands, forests, gardens and coastal lands. Some build holes in the ground covered with a trapdoor to hide their living areas. Some wolf spiders are nomads, simply wandering their entire lives hunting, mating and sleeping. Like almost all spiders, wolf spiders do produce venom, though it is weak and used mostly as a defense mechanism. Wolf spiders of California pose no threat to humans.
Crab spiders are so named because they physically resemble little crabs. Their legs arch upward in an angular fashion with the tips of their legs able to fold underneath their body. Also like the crab, the crab spider is able to move forward, backward and sideways. Similar to the wolf spider, crab spiders are hunters of prey. The do not build webs; instead, they ambush their prey. Once they have the prey in their grasp, they deliver a venomous bite to paralyze it. Even though they are venomous, crab spiders are not harmful to humans. Common species of crab spiders include the bark crab spider, flower spider, Xysticus and Misumena.
California is home to two of the most common dangerous spiders in America -- the black widow and the recluse. The black widow can be found all over California in dark areas. It can be identified by a large, black abdomen marked with a red hourglass shape. The venom of the black widow can cause cramps, fever, itching, nausea, difficulty breathing and increased blood pressure. The true brown recluse spider is not native to California. However, similar venomous brown recluse spiders do live in California, such as the desert recluse and the Chilean recluse. The Chilean recluse is characterized by its brown waist, spiky legs and and tan abdomen. The spider is one of the largest species of the recluse, growing up to nearly 1.6 inches in length. The desert recluse is similar in appearance to the Chilean recluse, though smaller; it grows to an average length of 0.7 inches. True to its name, the recluse can be found in dark, hidden areas. Hardly ever will a recluse be sighted in the open. The bite of a recluse can pose a serious threat to humans. Within 10 minutes, victims complain of itching, nausea and pain. The wound caused by the bite damages muscle tissue and forms ulcers. Immediate medical attention is recommended.