Pennsylvania is home to 37 unique species of spiders. These arachnids are one of the most feared creepy crawlies on the planet, despite often being harmless and providing free, natural pest control.
That being said, there are a handful of spider species that are dangerous and could potentially lead to fatalities if bitten.
Most Venomous Spiders in Pennsylvania
This article lists 8 spider species in Pennsylvania that you should take caution against if you ever run into them.
1. Broad-Faced Sac Spider
Credit: Judy Gallagher
Scientific Name: (Trachelas tranquillus)
The broad-faced sac spider has a dark brown head and abdomen. Their legs are a somewhat translucent red.
Where Will They Be Hiding?
The broad-faced sac spider can be found in silk cocoons they spin, nestled among leaves or under rocks. However, during the fall when temperatures begin to drop, these spiders make their way indoors.
Places that are seldom disturbed such as garages, basements, storage rooms, sheds, and attics are where these spiders will make their home. They feast on dead and decaying arthropods, so anywhere their food supply is plentiful they can be found.
Endemic to Northeast America, these spiders frequent warm and dry habitats.
Are They Dangerous?
The broad-faced sac spider tends to avoid running into people, but if you do come into contact with one it may bite out of defense. The bite itself resembles a very painful wasp sting.
Only a small amount of venom is transferred through the bite and is not enough to pose a major threat. Bacterial infections are more likely due to their diet of dead and decaying prey. Bit wounds should be cleaned immediately.
There are no recorded deaths or major secondary infections from broad-faced sac spider bites.
2. Long-Legged Sac Spider
Credit: Judy Gallagher
Scientific Name: Cheiracanthium mildei
Individuals range from brow to yellow to ivory in color. Their abdomen is darker than their head and legs.
Where Will They Be Hiding?
The long-legged sac spider is found across most of the United States apart from the Northern regions. They were introduced in Europe.
Sac spiders can be found outdoors walking among foliage or hidden under objects such as rocks. These spiders also venture indoors, frequenting homes and offices. They weave silken tents in dark corners and hide under beds and among clothes piles.
Are They Dangerous?
The long-legged sac spider is venomous, but its bite is non-lethal to humans. They will bite if they are startled or if they are getting crushed, such as if you accidentally pick up a pile of clothes where one is living.
The bite of a sac spider is painful and can result in swelling that may last for several days. The healing process is also rather slow.
Although a fair number of bite encounters have been reported, there are no known deaths from this species.
3. Black Widow Spider
Credit: Tyler C.
Scientific Name: Latrodectus various
Black widow spiders have large, oval-shaped abdomens. They are glossy, and jet-black with a bright red hourglass shape on their abdomen.
Where Will They Be Hiding?
Dark and woody locations are where this spider will likely be hiding. Outside, they frequent log piles, cracks and crevices, and foliage. Occasionally, these spiders will venture into urban areas, including human homes. They may hide under furniture or among clothes.
Are They Dangerous?
The black widow has a reputation for being one of the deadliest spiders. Despite their small size, their powerful venom is 15 times stronger than a rattlesnake. If bitten, it can cause vomiting, muscle fatigue, and even paralysis of the diaphragm causing breathing problems.
Bites are most deadly to infants, the elderly, and immunocompromised people. Around 4 to 8 people die every year from black widow bites.
4. Brown Recluse Spider
Credit: Br-recluse-guy
Scientific Name: Loxosceles reclusa
The brown recluse spider can be anywhere from pale to dark brown in color. They have a dark, violin-shaped patch on their thorax, earning them the name fiddle back spider, violin spider, or brown fiddler.
Where Will They Be Hiding?
Southeast America is the main range of this spider. They are frequent log piles, wooden crevices, and debris. These spiders often enter houses, where they can be found in cardboard boxes due to their rotting wood resemblance.
Are They Dangerous?
The bite of a brown recluse spider is dangerous and requires immediate medical attention. Their venomous bite leads to necrotic (rotting) skin lesions, potentially leading to hemolysis.
Despite the high number of annual reports of brown recluse bites, no fatalities have been recorded, although there have been cases of vulnerable people becoming seriously ill.
5. Woodlouse Hunter Spider
Credit: Dat Doris
Scientific Name: Dysdera crocata
The woodlouse hunter spider has a brown abdomen and a vivid red-orange thorax and legs. They are also called the sowbug hunter, sowbug killer, slater spider, and pillbug hunter.
Where Will They Be Hiding?
As their name suggests, these spiders feast primarily on woodlice. This means they are found in damp, dark habitats where woodlice are in abundance, including foliage and wood piles. Hence, they may be common in backyards, though avoid houses.
Are They Dangerous?
Although these spiders possess venom, they are not deadly to humans. Most recorded cases of woodlouse hunter bites are from when people are handling them. The dose of venom that is injected into humans is too low to be fatal, but nonetheless, the bite is painful and causes localized itching.
Common Spiders Found in Pennsylvania
6. Barn Funnel Weaver Spider
Credit: Spblat
Scientific Name: Tegenaria domestica
The barn funnel weaver spider is red-brown in color. Its abdomen is patterned with paler brown chevrons and its legs are adorned with black bands.
In Europe, this spider is known as the domestic house spider.
Where Will They Be Hiding?
Located across North America, Europe, Australia, Africa, and, Asia, the barn funnel weaver spider resides mainly in barns and sheds. They also frequent caves and the hollows of trees.
Females that take residence indoors can live for up to 7 years. They build funnel-like webs to catch their arthropod prey.
Are They Dangerous?
The barn funnel weaver spider is not dangerous. Despite commonly running into humans, they seldom bite. Even if they did, their bite is painless and not venomous to people.
There have been no documented cases of barn funnel weaver spider bites.
7. Wolf Spider
Credit: Judy Gallagher
Scientific Name: Lycosidae spp.
The wolf spider is dull brown overall, with a mottled pattern that helps them camouflage with its surroundings.
Wolf spiders get their name from their hunting technique. They pounce on their prey in a wolf-like fashion, instead of weaving webs to catch them. They are also called the ground spider or the hunting spider.
Where Will They Be Hiding?
Wolf spiders prefer to live on or very low to the ground. They can be found among plants, stones, and crevices. If they take up residence in your home, they are most likely to live around door frames, windowsills, and dark corners.
Are They Dangerous?
Generally, wolf spiders are not aggressive toward people and try to avoid them. They will only bite if provoked. Their venom is not strong enough to be lethal to humans, although the bite itself will likely be painful due to the large size of the spider and its mandibles.
Symptoms of Envenomation
Envenomation is the act of poison entering a body through the bite or sting of a living organism, such as a spider, snake, or scorpion. Depending on the dose and type of poison, there are a number of symptoms that can occur.
Spider bite envenomation symptoms include two, small, red puncture wounds on the skin where the spider bit you. These may be red, swollen, itchy, or painful. Additionally, the wounded area may bruise, blister and bleed.
Most symptoms however will be systemic. These include vomiting, nausea, diarrhea, muscle cramps, numbness, perspiration, increased heart rate, and difficulty breathing.
First Aid for Spider Bite Victims
If you are bitten by a spider, there are a number of universal, first aid measures that can be taken. Firstly, the wounded area should be cleaned thoroughly to minimize the risk of infection and help flush out the wound.
Ice can be applied to the bitten area to reduce pain and prevent swelling. In most cases, these measures should be sufficient.
However, if the bite is more serious, antibiotics should be applied to the wound, in order to help the healing process and prevent infection. Antivenom can be issued by a doctor if the bite is life-threatening.