The hobo spider is a type of funnel web spider that is very common in Utah. As a funnel web spider, the hobo spider builds a funnel-shaped structure instead of a web, and it is on/around this structure that the hobo spider takes shelter and attacks its prey. As reports of hobo spiders in Utah have become more common throughout the years, a debate has arisen about whether the spider is dangerous to humans.
In the early 1990’s, it was believed that the hobo spider was highly dangerous, with a bite that caused necrosis of the skin. In recent years, however, the consensus has become that hobo spiders are not significantly dangerous to humans.
Hobo spiders are nearly impossible to differentiate from similar-looking spiders without the use of a microscope. In general, hobo spiders have a brown cephalothorax that is connected to legs of the same color. The abdominal area of the hobo spider is a lighter color, with markings in colors of gray, black, and/or yellow.
Though hobo spiders are frequently confused with other common spiders, they are considerably smaller than their counterparts, such as the wolf spider or giant house spider. They typically grow somewhere between 7 to 17 millimeters, with females being larger than the males. The males have robust pedipalps near their mouths, which resemble stunted legs with tiny boxing gloves at the ends.
The clearest way to identify a hobo spider is by its solid-colored legs that do not feature the markings of similar spiders; however, this can be difficult to discern with the naked eye, and it is still not a guarantee that you are seeing a hobo spider. Hobo spiders typically have chevron-shaped markings on their abdomens, but this is not a reliable indicator due to many other species having similar markings.
Under a microscope, one would notice that hobo spiders have eight eyes in two rows, and their mouthparts have six to eight teeth. These and other small variances are relatively unique to hobo spiders when compared to similar species, but they are not noticeable without close, professional examination.
Hobo spiders are commonly found in the Pacific Northwest, but they have made their way to nearby inland states, such as Utah. Hobo spiders in inland states are believed to live up to three years, but these spiders in coastal areas have a life expectancy of just one year.
The males of the species will begin to look for a mate in summer. After mating, most males die afterwards or later in fall. The female produces up to four egg sacs in fall that will overwinter until the following spring when the eggs hatch. The mother spider will likely die before winter, but some may overwinter with the eggs and survive well into the following summer.
The spiderlings molt their skin inside the egg sac before emerging. Once hatched, the young spiders will remain close to the funnel web of their mother where they feed and grow. Depending on when they are hatched, some young spiders will overwinter once more before reaching full maturity the following spring.
As adults, the male spends most of its time wandering around looking for food and searching for a mate. The females construct funnel webs near debris and small crevices close to the ground. Once constructed, the funnel structures serve as a shelter for the spider, and it awaits prey to unknowingly walk into danger. The female will rarely wander far from her funnel web.
Habits And Habitat
In their native areas across Europe, hobo spiders are traditionally found in fields and forests where they prefer to build their funnel webs with a mixture of natural debris. Some house spiders in Europe are predators of hobo spiders, which deters hobo spiders from entering European houses. In the United States, however, hobo spiders are much more commonly found near homes and urban areas, as no such predator exists in the same areas as them.
While they are still found in warm, natural environments, hobo spiders will make homes in thick or unruly lawns, in shrubbery, between or under rocks, and many other areas in residential yards. Their funnel webs are built close to the ground, mostly due to hobo spiders not being the strongest climbers. While they can and will climb, hobo spiders have great difficulties climbing up slick/smooth surfaces; because of this, it is most common to find a hobo spider in your garage or basement.
As previously mentioned, the web of a hobo spider is weaved into a funnel shape that often utilizes small twigs, grass, and leaves to create a shelter. The same structure is used to trap prey. The female spends most of her time waiting inside the funnel for a victim to walk across the webbing. The hobo spider senses the vibrations of its prey on the web, and quickly springs out of the funnel to attack. Common prey includes smaller insects and bugs, such as flies, silverfish, cockroaches, etc.
How Dangerous Are They?
Though they are an aggressive species, hobo spiders are more likely to shy away from humans. There are reports of hobo spiders running towards humans when found inside homes, but this is likely attributable to the poor vision of hobo spiders. If you spot a hobo spider and it seems to run at you, it is probably trying to blindly scurry away from you in a panic.
Varying studies and reports still dispute the dangers of a hobo spider bite. In 2017, the CDC removed hobo spiders from their dangerous spider list due to minimal reports and a lack of evidence over the previous 30 years. Prior to that, it was widely believed that the bite of a hobo spider could cause giant blisters that burst into open wounds, painful ulcers, and even necrosis of the skin and muscle tissue near the site of the bite. Today, many experts believe that these bites were likely caused by similar-looking spiders.
If nothing else, the bite of a hobo spider will be painful and cause some swelling. Bites typically occur when the spider is physically touched by a person’s exposed hand, so be sure to wear gloves when moving things around in the garage or basement, and always look at what you are about to touch. If you believe you have spotted a hobo spider in your home, it would be wise to treat it as dangerous and proceed with caution.