Fall and early winter is prime time for spiders searching for warmer breeding grounds, and your home will do quite nicely for the randy Hobo Spider. Chances are, right now a male Hobo Spider is singing his own version of Barry White’s “Let’s Get in On” while making his way into your home in hot pursuit of a mate.
Hobos are a very common poisonous spider species in the Pacific Northwest, and we don’t want them near your curious kitty.
How to recognize a Hobo
The Hobo (Tegeneria agrestis), also called the “aggressive house spider,” is a European species that entered North America via the Port of Seattle between 1920 and 1930.
- The Hobo is most easily identified by its brown color with a lighter V-like pattern on the abdomen and large poison sacs near its face.
- The female is startlingly large, while the male is smaller but has larger poison sacs.
- Hobos usually range between ½-inch to 1¾-inch in body length and have long spindly legs.
Hobos are considered aggressive because of their willingness to attack. They weave funnel webs to catch insects, making flat, non-sticky webs often found near a home’s foundation or landscaping elements.
The Hobo’s inability to move on sticky or smooth, vertical surfaces is its ultimate weakness. He falls prey to other spiders’ sticky webs and can’t get out of sinks and bathtubs after seeking a drink.
Two kinds of Hobo Spider bites
For years, numerous reports of Hobo spider bites in the Northwest have been incorrectly blamed on the more infamous Brown Recluse spider because they have identical bite symptoms. The Brown Recluse however, doesn’t live west of Nebraska.
Hobos make two kinds of bites. About half are “dry,” where no venom is injected and the victim develops only minor redness.
A “wet” or venomous bite is not always painful, but a small, hard area typically appears within 30 minutes, surrounded by an expanding red welt that may reach several inches in diameter. Blisters form within 15-35 hours, which eventually crust over and the tissue beneath dies (becomes necrotic).
In severe cases, surgical removal of damaged tissue is required and may take months to heal, frequently leaving a permanent scar. A bite victim may also experience headaches, nausea, vomiting, and flu-like symptoms. No human deaths have been reported.
Don’t ‘sic’ your cat on a Hobo
Some articles state that cats are predators of Hobo Spiders. While many kitties love a good bug to chase, we do not recommend cats for Hobo control. For a good tummy churn, ask Dr. Monahan about the kitty patient who was bitten by a Hobo under the tongue, resulting in a large, very-slow-to-heal mouth wound. I
f you suspect your kitty has been bitten by a Hobo, please contact us right away at 206.323.4433 or seek emergency veterinary care.
How to control Hobos
- The single most effective deterrent against Hobo Spiders is the presence of competing spider species.
- The most preferred method of Hobo control is to eliminate suitable habitats and allow the orb weaver spider population (your typical garden spiders) to do its job.
- Pesticides are not recommended for Hobo control. Hobos are a highly mobile species and resistant to most pesticides, but other spider species are not. While the Hobos pack up and find better air quality, pesticides effectively kill all of their predators.
- Non-pesticide spider traps, found at most local hardware stores, may be helpful. They have a sticky surface with an attractant in the middle. Place the traps on the floor near doors, vents, first floor windows, and stairs, following package directions regarding placement to the traps away from pets and children.
If you have questions about Hobo Spiders, please check www.hobospider.org.
Hi all! I appreciated this post, especially considering a few experiences I’ve had this late summer and fall with startling large spiders. I have been curious to identify them, and this article left me slightly regretting letting go the one who scuttled past my bare foot in my kitchen a few months back! I clicked on the hobospider.org link at the end of the article to learn more, but it appears to be down (I got an error message each time I tried). Naturally, I turned to google and came across this article on hobo spiders from The Burke Museum’s blog. It appears that decades of research on the spider reveal that the general public’s beliefs about it and its medical importance are the subject of a great deal of non-factual myth.