Different Kinds of Spiders That Live in Oregon

It is estimated there is 500 species of spiders living in Oregon. While most of these live in the wild, there are some that are found in homes and other structures. These spiders can be either poisonous or non-threatening to humans and are not always found near webs.

Inside Spiders

• There are a variety of spiders found in houses and other inhabited structures in Oregon. It is possible to have spiders inside the building with no sign of a web -- these wandering spiders either wait and ambush their prey or move around to catch it. These spiders include the yellow sac spider, the ground spider (also known as the mouse spider), the running crab spider and the zebra spider. Spiders that use their webs to catch prey include the long-bodied cellar spider, the cobweb weaver, the funnel web spider and the American house spider.

Outside Spiders

• Many spiders are found in gardens, yards, parks and forested areas. Like those found inside, those found outside are both web-building and wandering. Wandering spiders include the common crab spider, the Enoplognatha ovata, the lynx spider, the wolf spider, the woodlouse hunter, the wolf spider, the jumping spider and the Tibellus oblongus. Web-building spiders are the common garden spider (also known as the cross spider), the grass spider, the Pimoa altioculata and the Hololena. The Enoplognatha ovata, Tibellus oblongus, Pimoa altioculata and the Hololena spiders have no common name.

Poisonous Spiders

• Oregon is home to several types of poisonous spiders. The most common of these are the hobo spider and giant house spider, which live in and around houses. These are usually found in late summer and early fall, and are most commonly found on the floor. The larger size of the giant house spider is one of the only differences between the two types. Bites from these spiders can lead to severe long-term tissue damage.

  According to the Oregon Department of Agriculture, the western black widow is most commonly found in eastern and southern Oregon. They are often found in dark spaces in and around the home, close to their web. The venom from black widows attacks the nervous system and can be serious enough to require immediate medical attention. The female black widow is easy to identify with a glossy, round body and a red hourglass shape on the abdomen.

  The yellow sac spider is a is non-web forming, preferring to hunt prey at night. They can be found both in and out of the home, hanging in sacs in corners and crevices. While there have been few confirmed cases of yellow sac spider bites being serious, these could possibly lead to long-term or severe tissue damage. The Oregon Department of Agriculture cites studies that document multiple cases of yellow sac spider bites with no long-term effects.

Spider Bites

• Despite popular belief, spiders rarely bite humans. Because spiders' mouths are formed to eat small insects, their chelicerae (the small pincers used to bite) often cannot open very wide, making it anatomically impossible for most spiders to bite humans - although there are some that can. The Oregon Department of Agriculture estimates most people will suffer only one or two spider bites in their lifetime.

  To avoid bites, keep the home free of clutter and vacuum often. Vacuuming in cracks and crevices as well as removing spider webs helps keep spiders away. Sealing windows and doors is also effective. When outside, wearing gloves and protective gear decreases the risk of being bitten. It is also important to check any places spiders may be before reaching in.