Common Venomous Spiders of California

At least 50,000 species of spider exist around the world, all of which use venom to subdue their prey. The strength of the venom varies from species to species, with only a small number of spider types being dangerous to humans. The state of California is home to a few species of spider whose bites can be painful and sometimes even fatal.

  1. Chilean Recluse

    • The Chilean recluse spider has been found in some areas of California, mainly in eastern Los Angeles County. It is one of the larger recluse spiders, measuring around 5/8 of an inch in length. These spiders are pale yellow to reddish brown in color. They are the most venomous of the recluse family, with a toxin that causes necrosis of the skin. Bites are painful, with symptoms that include nausea, fever and rash. The spider has been linked to several fatal bites in South America.

    Black Widow Spider

    • Many people, when asked to name a venomous spider, might say the black widow and they would be right. It is a common spider in temperate climates worldwide and is found commonly in California. Measuring 1.5 inches in length, the spider is black with a telltale red hourglass marking on its back. They are rarely aggressive and bite only when threatened. Black widow bites are not always fatal but they can be very harmful to children and the elderly. Symptoms of a bite include breathing difficulties, nausea and muscle pain.

    Hobo Spider

    • Originally from Europe, the hobo spider is common in Oregon and Washington as well as being on the rise in California. It is a small spider, less than an inch in length, and is brown in color with small, coarse hairs. Most bites from a hobo spider are dry, meaning no venom is injected, but those that are not can be painful and cause nasty ulcerations. Bites are not considered deadly, but can take a long time to heal, are very painful and can leave scars. Bites that are not treated and cleaned regularly can lead to more extreme problems such as amputation and bone marrow damage.

    Wolf Spiders

    • The wolf spider looks aggressive and dangerous, having thick legs and measuring up to 4 inches in length. They are very common in California and get their name from the way they will chase down prey like a wolf might do. They do have a strong venom which is generally not deadly, although it can do damage to the young or infirm. Bite symptoms generally cause a slight rash, soreness and swelling. Cleaning the wound will protect against spreading infections.