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What to Know About Hobo Spiders

Medically Reviewed by Mahammad Juber, MD on April 08, 2022

Hobo spiders were introduced to the US from Europe in the early 1900s. They are primarily found in the Pacific Northwest, including Washington, Oregon, Idaho, and Utah. Their name comes from the fact that they sometimes spread from city to city via railroads. 

These spiders have been the subject of much fear and misunderstanding, but they're largely harmless. They were once thought to cause "flesh-eating" bites, but this has been disproven. 

What Does a Hobo Spider Look Like?

It's difficult to identify hobo spiders because there are so many similar spiders. The hobo spider is a member of the family Agelenidae, which build funnel-shaped webs. The hobo spider is brown, has long legs, and can run up to 40 inches per second. 

They are between one-fourth and one-half inch in length. Though they have a distinctive chevron pattern on their abdomen, it's difficult to identify without a microscope and is more noticeable in juveniles. 

Hobo spiders don't have dark bands on their legs, so if you see a spider with this type of banding, you can be sure it's not a hobo. 

To make a definitive identification, you'll need a microscope to look for the following features: 

Plumose setae. These fine, almost clear hairs lay flat against the hobo spider's body. They look almost like feathers. Plumose setae are found in all Agelenidae, though, so they can't definitively identify a hobo spider. However, if your spider doesn't have these, it's definitely not a hobo. 

Six to eight teeth. Underneath their fangs, Hobo spiders have six to eight teeth on each side. Most common spiders have three to five teeth here. 

Eight eyes in two straight rows. The Hobo spider has eight eyes that are arrayed in two straight rows. Most other agelenid spiders have eyes that look like they're in a pattern of three rows with two eyes on top, four in the middle, and two on the bottom. 

Are Hobo Spiders Harmful?

Hobo spiders were once thought to cause necrotic wounds, which means the tissue in the wound has died, but there's no proof of that. In the 1960s, people in the Pacific Northwest who displayed necrotic bites blamed them on the brown recluse spider. However, the brown recluse isn't found in the Pacific Northwest. When the homes of people who had these bites were searched, hobo spiders were found, leading people to believe they caused the bites. 

One study conducted in1987 by Darwin Vest showed that rabbits who were bitten by Hobo spiders developed necrotic lesions. Additionally, one person had a verified bite that led to necrosis. However, that person had a pre-existing skin condition. The combination of these factors led to the hobo spider being placed on the "medically significant" list. 

Recent research, however, has contradicted this belief. In order to have a verified spider bite, you have to see the spider biting you, catch it, and have it identified. There have only been two people with verified hobo spider bites. In addition to the case listed above, one person experienced a spider bite on his calf. 

The only Hobo spider bite symptoms were local redness and some pain and twitching in the leg for 12 hours before it went away. 

Since many people in Pacific Northwest states such as Utah have hobo spiders in their homes, researchers would expect to see more cases if hobo spider bites were necrotic. Researchers have also not been able to duplicate the results of the 1987 study. In 2001, a similar study was conducted, with researchers injecting the venom into rabbits. Doing so showed no necrotic wounds. 

Where Do Hobo Spiders Live?

Hobo spiders are found in the Pacific Northwestern states. They are frequently found indoors from August through October, which is their mating season. They get into houses through cracks in the foundation or from broken screens or door sweeps. Males die after mating, and the females will go back outside to lay their eggs. 

Their feet are designed for walking on their webs, so they can't easily climb smooth surfaces such as painted walls or porcelain. Because of this, they're often found in basements at the ground level. However, they can climb rough walls, carpeted stairs, clothing, drapes, and bed skirts. 

Hobo spiders spin funnel webs that are shaped like little tornadoes, only wider at the top. They wait at the bottom of the funnel for their prey to get trapped in their web. 

Outdoors, they're found in the following places: 

  • Log or timber piles
  • Rock piles
  • Retaining walls
  • In tall grass that meets a foundation
  • Crevices in soil or concrete

How Can You Get Rid of Hobo Spiders?

Hobo spiders are beneficial, but there are times and places they aren't wanted. They're difficult to spot because they're active at night. You can monitor for Hobo spiders by placing a sticky trap around the baseboards of your home. This will let you see what type of spiders are in your home.  

You shouldn't use insecticide unless you have a large infestation. Insecticide may actually increase the population of hobo spiders by reducing the spider diversity. Additionally, insecticides aren't as effective against spiders. 

If your entryways aren't sealed, you'll still have hobos. Understanding why hobo spiders come inside will help you keep them out. Generally, they come inside for three reasons: 

  • To find a mate
  • To find food (other insects)
  • Because your home is easy to get into

Here are some steps you can take to get rid of hobo spiders and keep them from coming back into your house:  

  • Replace door sweeps on all outside doors. 
  • Seal any cracks that lead into your home with silicone sealant.
  • Install weather stripping around all doors and windows.
  • Vacuum regularly.
  • Minimize clutter inside and outside your house.
  • Move woodpiles away from your home.
  • Replace outside lights with sodium vapor lights that are less attractive to insects that spiders like to eat.

Show Sources

SOURCES:

University of California Statewide IPM Program: "Hobo Spider."

Utah Plant Pet Diagnostic Lab: "Hobo Spiders (Eratigena agrestis)."

Utah State University: "Hobo Spider Bite May Not Be So Dangerous."

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