The Hobo Spider

The hobo spider (Eratigena agrestis) 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/inside 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. Still, precautions should be taken if you suspect a hobo spider is in your home. Call Holmes Lawn & Pest at (801) 616-5296 for more information on spiders and pest control in Utah.

Appearance

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.

Key Characteristics

• Body length rarely exceeds 17mm
• Leg span between 1-2 inches
• Robust palps that look like stunted legs with tiny black boxing gloves (males)
• Smooth, solid-colored legs with no markings
• Chevron-shaped markings on abdomen
• Two rows of four eyes
• Mouthparts with six to eight “teeth”

Life Cycle

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. Females must show they are not hostile before the male approaches for copulation, but the male usually dies soon after mating.

The female produces four egg sacs that can contain up to 100 eggs each.  ➥  The mother spider overwinters with her eggs until they hatch in the following spring.  ➥  The spiderlings molt their skin inside the egg sac before emerging.  ➥  Spiderlings remain close to the funnel web of their mother to feed and grow.  ➥  Some young spiders will overwinter once more before reaching full maturity.  ➥  As adults, the males will spend their lives searching for food and a mate, and the females will rarely leave the 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 predators exist in these same areas. 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.

Hobo spiders’ funnel webs…

• are built close to the ground, as hobo spiders are not the best climbers.
• often incorporate grass, leaves, and other organic materials.
• are used to both protect the spiders and catch prey.
• send vibrations to alert the hidden female spider of approaching prey.
• are often found in low/hidden corners of basements and garages.
• commonly catch flies, silverfish, cockroaches, house centipedes, 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 that were misidentified as hobo 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 proceed with caution and assume it is dangerous.

We hope you enjoyed this article. Our last blog post on is a great read to learn all you need to know about the alarming huntsman spider. Our latest blog post is on another hunter type arachnid, the wolf spider.