Almost all spiders have venom, but most are too weak to do any harm. Though most spiders are relatively harmless to people, there are several spiders in Utah that are dangerous. Particularly a risk for young, elderly, or those who have a compromised immune system; black widows, hobo and wolf spiders have dangerous bites. Because it is important to understand the characteristics of these three common dangerous spiders, we at Rentokil have elaborated on the fundamentals.

Black Widow Spider Bite

Considered the most venomous spider in Utah and notorious across North America, the black widow spider is known for its distinctive appearance. Females feature a red hourglass shape on their underside and are about a half an inch long, with shiny black coloring a large globular abdomen. Females are the biters and deliver hazardous venom with them. Black widows are actually docile and will only bite protecting their eggs or if they get disturbed. The males are half the size of the females and are often eaten after mating. Black widows are more reclusive in nature, sticking to dark corners and crevices especially in garages, sheds, or other areas on or near the exterior of a home and are more active at night. The venom in their bites will have symptoms manifest in the first 20 minutes where the victim experiences local pain in the area of the bite. From there, weakness, tremor, as well as possible stiffness, cramps and spasms, abdominal pain, chest pain, chills, difficulty breathing, nausea, dizziness, fever and/or an increase in blood pressure and heart rate will develop. Where there is not an anti-venom for this, you need medical attention to treat the symptoms.

Hobo Spider Bite

Common in Utah, hobo spiders are part of the funnel-web spider family. They make funnel or cone-shaped, non-sticky webs and feature long legs. They do not exceed 2 inches long, but their sizes vary. They have a brown cephalothorax and darker brown markings. Grey abdomens with yellow markings are present but it can be difficult to spot without magnification. They are often confused with other spiders because of their generic appearance at first glance. Though hobo spiders are not climbers, they are very fast. They tend to keep to ground level and are frequently found in fields, around the brush, woodpiles, rock piles, foundation gaps, or other areas means of shelter. Inside homes, hobo spiders are commonly found in dark basements, hidden in window wells and sills, between objects, or in other protected and undisturbed areas. Depending on whether the bite is dry or wet dictates the severity of the bite. Dry means there was no released venom and the bite is not serious. Wet bites will immediately turn red that go away in a few hours. However, after a day or two, the blister breaks and the puncture develop into open, oozing ulceration. An erupting lesion that varies from pea size to larger than a half dollar or even a flesh hole that potentially leads to dead tissue will result if the bite is severe and untreated.

Wolf Spider Bite

Wolf spiders are commonly confused with tarantulas. These spiders can be dangerous. Dark brown and robust spiders, have eight eyes arranged in three rows; two large eyes on the middle row and two medium ones on the top of the head along with four small ones on the bottom row. Their size varies depending on sex and species, but generally, males are smaller than females. Fang marks are left after a bite and even skin tearing. Lasting up to 10 days, only redness, swelling and pain develops. Lymph glands may also swell.

Spider Control

No matter what type of spider species or other pests have come into your home, call Rentokil to remove them!