Spiders often appear in horror movies, haunted houses and, worst of all, inside our homes where they are usually met with shrieking and the bottom of a shoe. It’s easy to understand why people cringe at the sight of a spider on the wall. The way they move is startling and unpredictable, their webs are sticky and their hunting methods can be rather gruesome. There are also many myths floating around about spiders (no, people don’t regularly swallow spiders in their sleep!) that make this pest seem much scarier than it actually is. In reality, almost all types of spiders found in the United States pose no threats to people.
Despite the benevolent nature of most spiders, there are two species in the southern and western United States that can cause serious harm when accidentally disturbed – the black widow and brown recluse. Below is a guide to help you identify some of the type of spiders most common and the potential threat they can pose to your health.
Black Widow Spiders
- Appearance: Black widows are black and shiny, with a telltale red hourglass shape on the underside of their abdomen. Young black widow spiders appear orange and white, becoming darker and more black in color as they age.
- Region: This spider species is found throughout United States, but is most common in the southern regions where the temperature is warmer.
- Habitat: Black widow spiders tend to seek out dry and dark locations that are protected, such as underneath stones or decks, as well as in hollow tree stumps and in firewood piles. They can also be found in man-made structures such as sheds and barns. Black widow spiders spin their webs near ground level.
- Threat: While male black widow spiders rarely bite, females are known to be aggressive and bite in defense, especially when guarding eggs. Symptoms of a black widow bite include fever, increased blood pressure, sweating and nausea. Pain from a bite typically reaches a maximum in 1-3 hours. Fatalities are unlikely, as long as proper medical treatment is sought in a timely manner.
- Unique Facts: Black widow spiders are named after the popular belief that females eat their male counterparts after mating. However, this is a rare occurrence in the natural world.
Brown Recluse Spiders
- Appearance: Brown recluse spiders are light to dark brown, with a characteristic dark brown violin marking on their back.
- Region: This species is found in the central Midwest U.S. from Ohio to Nebraska and southward through Texas and Georgia.
- Habitat: Well known for their secretive or “reclusive” behavior, brown recluse spiders often live outdoors in debris and woodpiles. Indoors, they can be found under furniture, inside storage items and in dark recesses such as baseboards and window moldings. Closets, attics and crawlspaces are the most common hiding places of brown recluse spiders, as they provide warm, dry and dark environments.
- Threat: Like the black widow spider, the brown recluse spider bites in defense. Bites are usually not felt at first but can produce a stinging sensation followed by intense pain. Restlessness, fever and difficulty sleeping are common symptoms of a brown recluse spider bite. In serious cases, a bite can lead to an open, ulcerating sore that requires medical treatment.
- Unique Facts: Male brown recluse spiders wander farther from the nest than females and are therefore more likely to crawl into shoes or other attire. Additionally, while other spider species feed on small, flying insects, this species prefers small cockroaches and crickets.
- Appearance: House spiders are often yellowish-brown in color with an elongated abdomen, although their color can be highly variable.
- Region: Named after the fact that it is the spider species most commonly encountered indoors, house spiders are found worldwide and are common throughout the United States and Canada.
- Habitat: While this species can be found under furniture and in closets, they are most commonly encountered in garages, sheds and barns, where catching prey is easier for them. Outside, they are often found spinning webs around windows and under eaves, especially near light sources that attract potential food sources.
- Threat: House spiders are nuisance pests and pose relatively little threat to humans, but they may bite when threatened.
- Unique Facts: A female house spider can lay more than 3,500 eggs in their lifetime.
- Appearance: Jumping spiders are compact in shape with short legs, causing them to sometimes be mistaken for black widow spiders. They are usually black in color and covered with dense hair or scales that are brightly colored.
- Region: Jumping spiders are found throughout the United States.
- Habitat: Jumping spiders build web retreats, which can be found both indoors and outdoors. These spiders frequently hunt inside structures around windows and doors because more insects are attracted to these areas and their vision is best in sunlit areas. Outside, jumping spiders are commonly seen running over tree bark, under stones and boards, and on bushes, fences, decks and the outside of buildings.
- Threat: Jumping spiders may bite in defense, but their bite is not poisonous. In fact, this species is more likely to run from a human threat rather than attack.
- Unique Facts: Unlike most spiders, jumping spiders are active during the daytime and seem to like sunshine. They have the best vision of all spiders and are able to detect movement up to 18″ in distance. However, they can’t see very well at night.
Long-bodied Cellar Spiders
- Appearance: Cellar spiders are pale yellow to light brown in color with long, skinny legs and a small body.
- Region: There are about 20 species of cellar spiders found throughout the United States and Canada.
- Habitat: Cellar spiders are typically found in areas with high humidity and moisture, basements and crawlspaces. They can also be found in the corners of garages, sheds, barns and warehouses, on eaves, windows and ceilings, and inside closets, sink cabinets and bath-traps.
- Threat: Cellar spiders are not known to bite and therefore pose no threat to humans.
- Unique Facts: Cellar spiders are commonly referred to as “daddy-long-legs” because of their very long, thin legs.
- Appearance: Wolf spiders are usually dark brown with paler stripes or markings, and they have long, spiny legs. This species is often large and hairy, which can alarm some people.
- Region: More than 100 species of wolf spiders are found throughout the United States and Canada.
- Habitat: Wolf spiders can enter structures in search of prey. Once inside, they tend to stay at or near floor level, especially along walls and under furniture. Wolf spiders may be brought indoors with firewood. Outside, this species can be found under stones, landscape timbers, firewood, leaves and other debris. They often rest in such sheltered places during the day.
- Threat: Wolf spiders can bite, but it’s extremely rare unless they are provoked or handled.
- Unique Facts: Unlike most spiders, wolf spiders don’t hunt with webs. Instead, they actually chase down their prey using their fast running ability.
Dangerous or not, most people would prefer not to have any types of spiders in their homes. The best way to prevent spider infestations is to remove any possible harborage sites. Spiders are more likely to take refuge in dwellings during the colder months and will gravitate toward dark, undisturbed nooks and crannies. Therefore, homeowners should keep garages, attics and basements clean and clutter-free, avoid leaving clothing and shoes on the floor and seal off any cracks or crevices around the home from different types of spiders.