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Poisonous Spiders in Washington

Spiders are very interesting creatures. Different species of spiders can be found in almost any climate across the globe. They act as a natural form of pest control by feeding on insects or other spiders. Normally, spiders living in a home will never grow very large, and will tend to keep to isolated areas. Despite the beneficial services spiders provide, their appearance or the idea that they are all carrying deadly venom can bring up deep feelings of fear and revulsion in some people. All spiders carry venom that they use to subdue their prey, but there are very few species whose venom is poisonous to humans.

Western Black Widow
- The Latrodoctus Hesperus is a species of black widow that can be found in the Pacific Northwest. Their bodies are predominantly black, the females bearing a red marking on its abdomen sometimes shaped like a figure-eight, but their have been instances of white and yellow spots or stripes. Like most spiders, they find refuge in isolated nooks away from high traffic. They are venomous, the female being more so than males or immature spiders, but they are not aggressive and will usually only attack when provoked. Washington State University's Environmental Extension warns campers to check poorly built wooden privies (outhouses) as the collection of excrement attracts bugs, and spiders are known to build homes in them. Their poison will cause discomfort, but this will subside in two to three days. Medical treatment should be sought out only if the bitten is a child or an elderly person.
Hobo Spiders
- The hobo spider is an aggressive house spider. Hobo spiders are not native to Washington state, and it is believed they were carried on freight lines and have since they 1960s really established themselves in the area. Their eponymous webs are cone shaped and constructed in abandoned nooks found in or around the home like under floorboards, in piles of firewood, behind radiators, or tucked away in basements. Their venom is poisonous, and a bite will cause what appears to be nothing more than a mosquito bite, that is until the wound blisters and opens. These wounds can cause serious tissue damage that sometimes need to be surgically remedied, but there has never been a reported instance of death occurring from a hobo spider bite. These spiders are a furry brown color about one inch in diameter.
Funnel Web Spiders
- The funnel web spider or funnel weaver is a very aggressive house spider. They usually make their homes in moist, dark areas such as basements or crawlspaces. Their webs are specially designed to be open at both ends allowing the spider to move from one end to the other quickly when prey is entangled in the web. Their bites resemble a mosquito bite leaving a red bump. The male's venom is more potent that the female's, although both cause lesions on the skin much like a recluse spider bite.

Insects & Science