Hobo spiders, often a source of public concern, are not generally considered lethal to humans. While their bite can be unpleasant, fatalities are virtually unheard of. This article clarifies common misconceptions and details the reality of hobo spider bites.
Identifying Hobo Spiders
Hobo spiders (Eratigena agrestis) are medium-sized, typically ranging from a half-inch to an inch in body length, with a leg span up to two inches. They are usually light to yellowish-brown, and a distinguishing feature is a pattern of “chevron” yellow markings on their abdomen, which may require magnification to observe clearly. Unlike some other spiders, hobo spiders do not have distinct dark bands on their legs.
These spiders are members of the funnel-web spider family, constructing funnel-shaped webs in sheltered areas. Their webs feature a tubular retreat where the spider waits for prey. Outdoors, hobo spiders are commonly found in woodpiles, rock piles, tall grass, and foundation cracks. Indoors, they prefer dark, undisturbed locations like basements, crawl spaces, and storage rooms, typically staying at ground level as they are not skilled climbers.
The Reality of Their Bite
A hobo spider bite typically causes mild pain and redness. Symptoms can include a slight prickling sensation at the bite site, and some individuals may experience localized swelling. In some cases, a severe headache, nausea, and fatigue have been reported within minutes or hours after a bite.
Despite past concerns, there is no significant scientific evidence to suggest that hobo spider venom causes necrotic lesions or is medically toxic to humans. The Centers for Disease Control and Prevention (CDC) does not list hobo spiders among venomous species toxic to humans. Studies where hobo spider venom was injected into animals, such as rabbits, failed to produce necrotic wounds.
If bitten, clean the area with mild soap and water and apply a cold compress to reduce pain and swelling. Seek medical attention if symptoms worsen or persist, as secondary infections are possible with any spider or insect bite.
Understanding the “Killer” Reputation
The hobo spider’s reputation largely stems from historical misidentifications and misunderstandings. Before the brown recluse spider was widely recognized, particularly in the Pacific Northwest, many necrotic lesions were mistakenly attributed to hobo spider bites. However, brown recluse spiders are not found in the Pacific Northwest, prompting a search for alternative explanations for these skin conditions.
Many bites once thought to be from hobo spiders were likely caused by other factors, including other arachnids or bacterial infections like MRSA. The spider’s former common name, “aggressive house spider,” was a misinterpretation of its scientific name, agrestis, which means “of the field” and describes its natural European habitat.
The scientific community has largely re-evaluated the severity of hobo spider venom, concluding that it poses minimal medical concern to humans. This shift highlights how perception and historical context shaped public fear, rather than the actual biological threat.