Last night I was scrolling through my Facebook news feed when I stumbled upon a supposed â€œUSA Spider Chart.â€ The chart, which is shown below, has numerous false and erroneous spider accusations; something the spider must be well acquainted with by now. One such error happened to be that the Hobo Spider is a deadly and dangerous spider, grouped together with the Black Widow spider and the Brown Recluse spider. See for yourself:
THIS INFORMATION IS WRONG! The Hobo spider that is found in the United States is not deadly, and is not as dangerous as the Black Widow or Brown Recluse. Let’s clear up this common misconception about the misunderstood Hobo spider.
Are Hobo Spiders Dangerous?
Many of us cower in fear at the thought of a spider. If there is even an inkling that the spider might be lethal, we’d run screaming the other direction looking for the nearest flamethrower to take the spider out. It is misconceptions, like that of the Hobo spider, that lead many of us to feel the way we do about spiders.
Hobo spiders are not deadly. Hobo spiders are not dangerous. In fact, a recent study from The National Center for Biotechnology Information and The US National Library of Medicine states that the Hobo spider is relatively harmless.
It was believed for a long time that Hobo spider bites can leave a necrotic (rotting flesh) wound that progresses over several daysâ€”similar to that caused by a Brown Recluse spider bite. In the study entitled The Misdiagnosis of Spider Bites, the venom from a Hobo spider was shown to not produce necrosis in humans, and in didn’t even produce necrosis in rabbits; which was believed to be the case after an earlier study on rabbits was released decades earlier.
Additionally, the study found Hobo spider venom was not deleterious, harmful, dangerous, or toxic to ANY vertebrate red blood cells.
It’s important to note that the Hobo spiders mentioned in the studies and in this blog post are the Hobos that are commonly found in the United States. Hobo spiders found in Australia can have a nasty bite.
How The Hobo Spider Myth Got Started
It’s believed that the Hobo spider myth started after the spider’s venom was injected onto a rabbit decades ago, and it caused necrosis of the rabbit’s skin. The above mentioned study proved the rabbit’s necrosis to be false, as the more recent study performed with up-to-date technology caused no such necrosis. The study also suggests that human related Hobo spider bites do not cause necrosis.
I searched medical literature on Hobo spider bites, looking for instances in which a Hobo spider has caused necrosis or death, and found very little. I did find one case of a verified bite by a Hobo spider that resulted in a necrotic skin lesion, and this was in a person who had a pre-existing medical condition which can also lead to necrotic skin lesions.
The funny thing is that mites, fleas, bed bugs, soft ticks, hard ticks, conenose bugs, and kissing bugs would be far more likely to cause necrotic-type wounds than a Hobo spider bite; pests that don’t have the same rap as spiders do.
As far as I can tell, this Hobo Spider myth got started by fear mongering arachnaphobs perpetrating more spider hate.
Identifying A Hobo Spider
If you are resident of the Pacific Northwest, you are very well acquainted with the Hobo spiderâ€¦ or at least you think you are. The fact is that most people in the states of Washington, Oregon, Idaho, and Utah, in which the species is commonly found, refer to any big spider they see as a Hobo spider. As spider control professionals, we have found that many well-intentioned people call non-Hobo spiders as Hobo spiders. Giant House spiders are commonly confused for hobo spiders.
The truth is that Hobo spiders are very difficult to identify by the naked eye. Some people use a spider’s coloration to determine the species. The problem with this is that similar spider species often times overlap in their appearance with Hobos. Even experienced arachnologists have a difficult time identifying Hobo spiders, and rely heavily on hand lenses and microscopes to identify them.
True Hobo spiders are brown, with a large abdomen, and measure in length from 1/4th to 5/8 of an inch long. One of the easiest ways to determine if a spider is indeed a Hobo spider is to look at it’s web-building. Hobo spiders build funnel webs. To identify a Hobo spider with 100% accuracy, the spider in question must have its eyes and reproductive structures examined by an experienced entomologist.