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Spiders of the Pacific Northwest, United States

Some of the most plentiful creatures in the world, spiders are present in almost every environment on Earth. With 30,000 known species, spider species in any given geographical area may number in the hundreds or even thousands. In the Pacific Northwest, there are 760 species in Washington alone, many never seen by humans. The most common species of spider in the region reside everywhere from woodlands and near water to home gardens and basements.

Cross Spider
- A cross orb weaver spider with white markings on its back
  
  One of the most common spiders in the Pacific Northwest is the cross spider (araneus diadematus). A type of orb weaver spider, the cross spider spends the majority of its life in a vertical web, which is rebuilt every day. Generally identified by a diamond-shaped abdomen and a group of white markings in the shape of a cross on its back, the cross spider also displays varying shades of brown, tan and yellow. Growing as large as 2 centimeters, the cross spider is not dangerous to humans.
Garden Spider
- A garden spider with yellow and black markings on its back
  
  Another type of orb weaver spider found in the Pacific Northwest is the garden spider (argiope aurantia). A close relative to the cross spider, the garden spider also spends most of its life in vertical orb-shaped webs. Identified by an oval-shaped abdomen and black and yellow markings on its back, the garden spider has black legs and grows very large. Despite its size, the garden spider is harmless to humans and is a handy helper in a garden, eating unwanted pests like the mosquito.
Wolf Spiders
- A wolf spider is often black, gray or brown with a hairy body.
  
  Large and hairy, the wolf spider, from the family Lycosidae, is another species of spider found in the Pacific Northwest. Constantly mobile, wolf spiders have no nest or web, spending their entire existence on the ground, with females carrying egg sacs and young on her back. They catch their prey by stalking and chasing, and they are swift runners. Able to grow to almost 4 inches long, legs included, the wolf spider is intimidating, but its sting is rarely harmful, unless the victim is allergic to the venom.
House Spiders
- Three spiders commonly found around the home or garden are members of the Tegenaria genus and include the domestic house spider, the gigantic house spider and the hobo spider. All three of these species make funnel webs and all display brown and black coloration. However, the domestic and gigantic varieties of these spiders are generally not dangerous to humans, while the hobo spider can cause severe bites. Often described as aggressive, the hobo spider bites mainly when accidentally pressed against the skin.

Animals & Science