As of 2021, there are around 40,000 known species of spiders worldwide, with about 3,000 of them calling North America home. With so many types of spiders out there, knowing which spiders are the most common—and which are potentially dangerous—isn't always easy.
Identifying spiders, or arachnids, is complicated and can often require a trained professional with a powerful microscope for final identification. Luckily, in most at-home cases, all it takes is some simple knowledge of spider biology to determine what species or type of spider you could be dealing with. From there, it's a relatively simple matter to find the right type of spider pest control.
While there are many common types of spiders throughout North America, it is important to know that only a handful of spider species intentionally dwell inside houses. Other species occasionally stray inside but are more frequently carried into homes by accident on things like flowers or firewood.
It is not unusual for people to feel afraid of spiders. This widely held fear of spiders can often fuel some misconceptions about spiders which can, in turn, lead to ineffective and unneeded chemical treatments to deal with spider nests or other infestations.
If you believe a chemical spray or treatment could be needed to get control of your house spider issue, think before you spray. Spiders do not react as strongly to chemical treatments as other insects unless they come into direct contact with the spray itself—contact with residue alone is not enough to kill spiders. Pest control strategies that properly address a spider's biology can make chemical applications less necessary (or even completely unnecessary). Aim to remove spiders, egg sacs and webs from your house to reduce numbers long-term. You can do this using a vacuum, broom or spider brush with an extendable handle.
Common Types of Spiders Without Poisonous Bites
Common House Spider
Achaearanea tepidariorum, also known as the common house spider, is just what the name implies: incredibly common. Also known as the American house spider or the domestic spider, these arachnids are the most regularly seen spiders in all of North America, with sightings ranging from Southern Canada throughout the United States.
If you have noticed dirty cobwebs in the corners of your walls, they very well could have been left by a common house spider. These dust-covered cobwebs can easily be vacuumed up or swept down without fear of coming in contact with a spider. Common house spiders choose web locations at random and will readily abandon their web to build one elsewhere if their chosen spot does not result in a meal. When they leave, they ditch their old web, leaving it behind to collect dust.
The two most common cellar spiders are short-bodied cellar spiders and long-bodied cellar spiders. They are found throughout Canada and the United States and tend to build their webs in dark, moist environments such as cellars, warehouses, barns, and garages, where they spend their days eating insects and other spiders.
Many people mistakenly believe that long-bodied cellar spiders have venom that would be lethal to humans if the spiders' weak mouthparts were capable of biting skin. While it's very true that long-bodied cellar spiders have no ability to pierce human skin with their jaws, their venom is not potent, making these spiders harmless pest-eaters.
Harvestmen, also known as daddy long-legs, are not technically spiders. They are actually a distant relative of the spider and get an honorable mention because they are frequently confused with the above cellar spider.
When trying to determine if you're dealing with cellar spiders or harvestmen, look at their body shape. Cellar spiders are a yellow color and have two distinct body parts including a long, skinny abdomen. Harvestmen have two body segments as well, but they don't look like it. Their body looks like it has a single, brown or grey oval shaped segment with eight spindly legs protruding from it. Harvestmen are not venomous and are typically found outside in spaces such as wooded areas or gardens.
There are a variety of jumping spider species through the United States and parts of Canada, but they are all part of the family Salticidae. Jumping spiders are hunting spiders that are capable of jumping up to six inches, depending on the species. These spiders commonly wander into homes but can also be carried in on firewood or plants.
Many jumping spiders have red or white markings on their abdomens and can be confused for black widows. Jumping spiders, however, are not dangerous and are actually beneficial, as they enjoy hunting and pouncing on nuisance insects.
Funnel weavers, including the hobo spider, are part of the family Agelenidae and are most noticeable in the fall when their dew covered webs are visible in the morning hours. Not to be confused with the funnel-web spider of Australia (the only spider in the word that is considered actually aggressive), funnel weavers build their webs in a variety of places including windows, doorways, and cellars.
It was long believed that hobo spiders had a dangerous bite. Reactions vary from person to person, but hobo spiders are not considered toxic to humans according to the University of California's Pest Management Program.
Frequently confused with tarantulas, wolf spider are large, hairy hunting spiders that do not construct webs but instead spend their lives running from place to place seeking out food sources. Part of the family Lycosidae, wolf spiders are found throughout North America north of Mexico. These are primarily outdoor spiders that hunt nocturnally. If you're seeing one inside, it's likely looking for dinner.
Interior insect monitors are glue traps that can be a valuable tool used to reduce the number of interior hunter spiders in your home. Place them up against the wall or behind dark, damp areas where spiders hide and use them to determine what types of spiders are most active in your home and where.
Common House Spider Bites
Before getting into house spiders that have poisonous bites, it's important to understand that more often than not, spiders are not aggressive and do not bite. Spiders would much rather run away from people as opposed to bite them, and spiders are more likely to bite when they feel threatened.
Don't be too quick to assume that an itchy bump is a spider bite. In The Handbook of Pest Control, written by renowned entomologist Arnold Mallis, it is noted that many insect bites and stings, and even some non-pest related skin infections, can all cause similar skin reactions. It is not uncommon for an irritation to quickly be misdiagnosed as a spider bite when it could have been caused by something else.
Common Types of Spiders With Poisonous Bites
Part of the family Miturgidae, sac spiders are normally found inside (or outside) homes. They use their silk to construct tent-like coverings in low corners. They hide behind these silky structures during the daytime, resting before their nocturnal hunting starts.
There are not reliable visual distinctions used to identify sac spiders. They vary drastically in coloring and are sometimes confused with other spiders due to shades ranging from yellow to brown to green. It's a good idea to keep your distance from these spiders, as their venom contains cytotoxin and has been shown to be poisonous to humans. Use a vacuum or broom to clean them up. Don't want to do it yourself? Hire a local IPM specialist.
What Is Cytotoxin?
Cytotoxin is a toxin that affects the body's cells. The cytotoxin in sac spider venom can cause the bite to be quite painful for an extended period and can cause the wound to heal much slower than usual.
Brown spiders, also known as fiddle-back or violin spiders, are a part of the Sicariidae family. Some are harmless, but this group of spiders also includes the brown recluse, the most dangerous spider of the Loxosceles species.
Identification of brown spiders can be difficult because they all have very similar markings and colorings. If you suspect the spider you're seeing is a brown spider, give it space. Luckily, they are not aggressive and are not likely to bite unless pinned against skin. It is most common for brown recluse bites to happen on the arms, hands, and feet while doing things like dressing or cleaning storage areas. These bites can often go undetected until hours later when the discomfort sets in.
If you are concerned about brown recluse spider and live in an area where they are known to be present, before getting dressed, shake out any clothing that is left overnight or stays outside (including shoes), make sure you're not going to lay down on any spiders before climbing in bed, and wear rubber gloves when cleaning out storage spaces or moving firewood.
Brown recluse spiders are found most often in the midwestern and southern United States. These spiders are naturally found outdoors in areas where hiding places are readily available, such as debris piles, bark, raked leaves, between or under stones, and within wood piles. These spiders are also well adapted to indoor habitats and will venture into storage areas, closets, attics, and other dark hiding spots.
If you suspect you have been bitten by a brown recluse, ice and elevate the bite while you monitor it. According to the CDC, the venom of a brown recluse can sometimes destroy skin tissue around the bite area, causing a serious lesion, or skin necrosis, to form. If a bite continues to worsen or you suspect a lesion is forming, consult a doctor for medical care.
Widow spiders are certainly not one of the most common types of house spiders, but they're at the top of the list when it comes to spider related concerns. If you're seeing a spider in your home, it is likely not a widow spider, but it's still a good idea to know what to look for and how to avoid disrupting them.
Widow spiders range in color, as there are both brown and black widows, but both have a distinct reddish-orange hourglass shape on the underside of their abdomen. There are also false widows, which look similar to a black widow but are completely harmless.
Black widows are widely known for the toxins associated with their bite, but keep in mind that black widows are very shy. They generally hide in areas that are not commonly accessed and are not likely to bite, as they are not aggressive and rarely leave their webs.
It is during the period of time after laying eggs and guarding their egg sacs that a black widow is most likely to bite, but only when disturbed. If you need to be reaching into an area where a spider could be hiding, such as a woodpile or rarely touched storage space, wear rubber gloves to protect yourself from possible spider bites.
According to the CDC, symptoms of venomous spider bites vary depending on the person and species of spider. Venomous spider bite symptoms include, but are not limited to, itching and rash, pain and aching (including head and muscle aches), perspiration, elevated blood pressure, and nausea. If you suspect you have been bitten by a venomous spider, seek medical attention and do your best to identify the spider if possible. If a specimen of the spider is available, save it in a container and cover the specimen with 70 percent ethanol or rubbing alcohol to preserve it, as proper identification will help determine the best treatment options.
Removing Common House Spiders
Even though most common house spiders don’t pose a threat to humans, you may not want them sharing your home. If you have an invasion problem, there are plenty of ways to control spiders. If you’d rather not fight them on the front lines, you can find help from a local IPM specialist to help out.
Crawford, Rod. "Myth: Spider 'Infestations' Should Be Controlled With Pesticides." The Burke Museum.
Pests of Homes, Structures, People and Pets. Statewide Integrated Pest Management Program, University of California Agriculture and Natural Resources.
Mallis, Arnold. The Handbook of Pest Control: The Behavior, Life History, and Control of Household Pests. Mallis Technical Handbook and Training Company, 2011.
Vassilevski AA, Fedorova IM et al. Novel class of spider toxin: active principle from the yellow sac spider Cheiracanthium punctorium venom is a unique two-domain polypeptide. J Biol Chem., vol. 285, no. 42, pp. 32293-302, 2010. doi:10.1074/jbc.M110.104265
Types of Venomous Spiders. Centers for Disease Control and Prevention.
Symptoms of Venomous Spider Bites. Centers for Disease Control and Prevention.