America’s 3 Most Dangerous Spiders

A spider bite is the last thing you need when civilization as we know it is collapsing – or even just camping out. Even arachnophobes – people who are terrified of the eight-legged creepy crawlies – need to know which spiders carry venom strong enough to inject a killing dose.

That said, anyone who read Charlotte’s Web knows that the vast majority of spiders are harmless helpers who eat household and garden pests and spin pretty webs. Most spiders are soooo not aggressive – they are much more afraid of you.

Despite all those horror movies where mutant spiders run amok, they are seldom killers. One disarming fact is that “during the whole 20th century spiders were responsible for in the region of only 100 deaths globally.”

Avoiding dangerous spiders in the first place is the best plan but what would you do if someone in your group started reacting to spider poison?

The good news is that there are only three deadly and dangerous types of spiders in the United States. There are four more varieties which are quite toxic with a painful bite. If you value your health and well-being, get familiar with these seven spiders – just in case.

In general, male spiders have longer legs, a smaller abdomen, and enlarged or swollen pedipalps (palps) which are the second pair of appendages, , used for reproduction, located behind the first pair of walking legs and lateral to the jaws.

People with allergies or who are hypersensitive to spider venom may have stronger, dangerous reactions from the bites of lower-risk spiders like Mouse, Black House, Wolf, Trap-Door, Garden Orb-Weaving, Saint Andrew’s Cross, and Huntsman. When that happens, treat these victims as if they had encountered a spider considered more deadly.

THE TOP 3 DEADLY AND DANGEROUS U.S. SPIDERS

If you known (or even suspect) that someone has been bitten by one of the following three spiders, treat with First Aid:

• Keep the patient calm (this slows the spread of the poison through blood circulation)
• Apply ice (to decrease the pain and reduce swelling)
• Take anti-inflammatory medications (for pain relief)
• Contact a doctor

1. Brown Recluse (Loxosceles reclusa)

Also known as violin spiders, fiddle-backs, and reapers, all recluse spiders live in warmer climates around the globe. They range from the east coast of the United States to the west coast, mostly in southern states: from the center of Arkansas, south-eastern Nebraska, Kansas, Oklahoma, Texas, Louisiana, Arkansas, Missouri, Kentucky, Tennessee, Mississippi, Alabama, northern Georgia, southern portions of Ohio, Indiana, Illinois, and Iowa.

The brown type is considered to be the most dangerous of the recluse spiders. Its venom is necrotic (flesh-eating). In severe cases, the flesh around the bite begins to die, forming a deep, open sore that can take months to heal. No treatment is known other than skin grafts.

The body of a brown recluse spider measures 1/4 to 3/4 inch. One distinguishing feature is that there are only six eyes (three pairs of two on each side of the head) instead of the usual eight that most spiders have. The other way to identify a brown recluse is by a dark violin shape where the legs attach with the neck of the violin pointing backward toward the abdomen.

Recluse spiders are shy – reclusive – and shun human contact, when possible. They will respond to a direct threat but won’t go out of their way to sneak up and pounce on you. They also have small fangs which limit how much toxin they can deliver per bite. Reports indicate that recluse spiders are immune to some insecticides, which “only make them more toxic and angry!”

There are things you can do to avoid them, too:

• Shake out items such as gloves, boots, shoes, clothing and blankets before using them, especially if they are not used often or have been in storage
• Warn the spiders by making noise or vibrations (i.e. stomping your feet) before entering basements, attics, storage areas and unused closets
• Avoid clutter since brown recluse spiders hide in or between or under items in your home
• Deploy glue traps
• Contact a professional pest control operator to deal with a home invasion
No antidote for brown recluse venom exists so treatment focuses on relieving the symptoms:
• Antihistamines to relieve itching
• Corticosteroid creams and lotions to limit inflammation
• Antibiotics to prevent or treat infection
• Intravenous fluid therapy (IV)
• Surgery may be needed for deep or infected wounds
• Tetanus vaccinations must be up-to-date; a booster is usually given if the patient’s vaccine status is unknown

2. Black Widow (Latrodectus mactans)

The Southern Black Widow (or, simply, Black Widow) has a famous reputation as a very dangerous critter.

The black widow’s trademark feature is the red hourglass on the female abdomen. Black widows are so named because, once in awhile, the female eats her mate after sex. These spiders are native to North America.

Black widows shun human contact yet hide in places with lots of them. I have seen them in their dense, sticky webs under the seat bottoms of the kitchen chairs on a Southern California high-desert ranch house. The residents carried on without even realizing the beasties were so close to their legs and tender bits. None of these spiders attacked anyone – the scorpions outside were a far greater threat.

Once bitten, expect burning pain, swelling that spreads from the bite area, abdominal cramps, nausea, and sweating. Very old and very young people are at the highest risk of death from a black widow bite.

The smaller male black widow spiders inject much less poison than the females but all of them can be harmful, if not life-threatening. The only known therapies are opioid analgesics (pain killers) and black widow spider antivenom.

Here are some tried and true ways to avoid making contact with black widow spiders:
Outside

• Take out the trash (especially woodpiles, boxes, plywood, tires, empty containers)
• Trim tall grass, weeds or shrubs (especially near the foundation of your house)
• Inspect and/or shake items that have been stored in the garage or in a shed or outdoors for spiders, webs or sacks before bringing item indoors
• Store gloves and shoes in sealed plastic bags or containers
Inside
• Keep beds away from the walls and don’t store boxes or any items underneath
• Keep dust ruffles or bed skirts from touching the floor
• Don’t store shoes on the floor or any clothes, towels or other linens – and always shake out shoes and clothes before using
• Store sports equipment (roller-skates, gardening clothes, gloves, ski boots) in tightly sealed plastic bags with no holes
• Vacuum under furniture, closets, heaters, around all baseboards, and other areas of the house to eliminate habitat
• Keep screens on windows and fix or replace screens with holes or that don’t fit snuggly
• Seal doors with weather stripping and door sweeps
• Seal cracks and access holes for electrical conduits or plumbing
• Remove spider webs and egg sags when found

3. Hobo (Tegenaria agrestis)

Bites from the Hobo spider also produce necrosis (tissue death) and an open wound that takes a long time to heal. Even though hobo spider venom is less toxic than that from a brown recluse, these arachnids are hunters and will actively seek out human prey.

Since they are so aggressive, some people believe that bites attributed to brown recluses were really caused by hobo spiders. The poison causes less necrosis than a brown recluse. Other symptoms include headaches, vision trouble, and feeling tired.

Hobo spiders are a recent arrival in North America, having come here from Europe. They have become a common residential pest here, unlike in Europe, because house spiders across the Big Pond are even bigger and meaner, if you can believe that.

Due in part to their novelty, there is no treatment specific for hobo spider bites. Doctors follow the procedures used for brown recluse spider bites.

Sometimes, a hobo spider will bite without injecting any venom. Many times, the bite itself goes unnoticed. It is only when pain and angry red swelling appear that the patient may suspect a spider attack. The best thing to do is to immediately clean the wound area with warm soapy water, dry, and cover with a sterile bandage or gauze to prevent infection from dirt and bacteria.

Although hobo spiders prefer to build their funnel-shaped webs outside in trees and under rocks, they do come inside sometimes to set up residence. Females lay hundreds of eggs during breeding season so it’s easy to understand how things could get out of control rapidly.
For hobo spiders, the ounce of prevention will be well worth the pound of cure (or flesh). Keep them out of your house:

• Seal up cracks around door and window frames, and make sure there are no holes in your siding
• Since the funnel-shaped web goes from the ground to an overlying surface, keep bedspreads off the floor and away from walls
• Keep your home clean; vacuum corners and crevices where hobo spiders like to live
• Spray pesticide around the perimeter of your home to prevent the spiders from coming inside, following the manufacturer stated directions before applying any home pest control spray
• Invest in hobo traps, specifically designed to catch hobo spiders when placed in spider-friendly locations – if you catch one, wear gloves and approach the trap cautiously because even a disabled spider can still inject a venomous bite
• Diatomaceous earth is a natural alternative to chemical pesticides, a substance consisting of small fossils that work to destroy the protective exoskeleton of spiders – after contact with it, the pest will eventually dehydrate and die so sprinkle it generously around the outside of your home
• Hire a professional pest control contractor if an infestation is present

If you can capture a spider you think bit someone, take it to the emergency room in a sealed container. “Some doctors and medical facilities have access to an anti-venom, or medication that can reverse the effects of the spider’s toxin within the first 4 to 12 hours.”

The itsy-bitsy spider was no match for the water spout but the brown recluse, black widow, and hobo spiders are formidable adversaries when aroused.

Remember to stay calm and take quick action for suspected spider bites. Your life might hang in the balance.