America’s desert southwest is chocked full of wildlife of every shape, size and species. But some are dangerous and can cause injury or even death even though they are amongst the smallest of the animal kingdom. Desert spiders of the southwest United States are some of those that can pack a mean punch should you encounter them. So, it’s best to just stay clear of these venomous arachnids!

Unlike friendly storybook and nursery rhyme spiders like Charlotte (Charlotte’s Web), Little Miss Muffet and Itsy Bitsy Spider, real life desert spiders aren’t so friendly or harmless. In fact, some are venomous and considered dangerous should you get bit.

While this article pains me to write (because I absolutely LOATHE spiders), it’s important to know which spiders in the desert southwest you should stay clear of while you’re camping, hiking or playing outdoors.

So, let the creepy crawly heebie jeebies begin!

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5 Dangerous Desert Spiders to Avoid in Southwest United States

Desert Tarantula

Desert Tarantula Spider

The Desert Southwest consists of the Sonoran Desert, Mojave Desert and Chihuahuan Desert. The most familiar desert spider that lives in all of those comes as no surprise; the Desert Tarantula.

But, contrary to popular belief, though this big hairy spider looks creepy, he (or she) is not as dangerous as everyone thinks.

So, don’t let their big creepy size fool you into thinking they’re going to kill you. While they may scare arachnophobes to death, they seriously won’t kill you.

National Parks Traveler states in their Creature Feature article, “The Desert Tarantula Looks Big, Hairy, and Scary”,

“Many people think that tarantulas are quick to bite people, and that the bites are very dangerous. Neither assumption is correct. Since a tarantula has a rather gentle disposition, and would rather flee than fight, it rarely uses its fangs for anything except catching and mashing up prey.

And while it is true that a tarantula may inflict a painful bite on a human if sufficiently provoked, the bite hurts less than a bee sting and poses no serious hazard unless the bite becomes infected or the victim has a severe allergic reaction.”

And, I’m here to back up that statement. My first close encounter with a Desert Tarantula was when we visited Rhyolite National Historical Site. And let me tell you, he was on a fast trot trying to either make his way home or escape from something chasing him (or us!).

And three years later, while we were hiking at Big Bend National Park, we encountered hundreds of Tarantulas.

Hence, the photo above that I courageously took during our visit. And, by the way, they DO look like little teddy bears when they rear up on their hind legs!

Cuteness aside, it is best to stay clear of these big hairy desert spiders. Because if you do get bit out in the desert southwest, you could be miles from seeking medical attention should you have an allergic reaction.

Wolf Spider

Desert Spiders - Wolf Spider

The Wolf Spider is by far, the scariest looking spider. They are quite common in the southwestern desert regions of the United States.

Measuring up to one and a half inches in length, they range in color from gray to dark brown. They have a flash of pale orange to bright orange color at the anterior portion of the chelicerae.

Considered an expert hunter spider like the Tarantula above, this desert spider also goes out at night to search for its’ prey. Instead of catching prey in a web, the wolf spider will chase down and pounce on its prey.

Wolf spiders live in borrows and hide during the day. From March to October is their active season.

Wolf spiders are primarily nocturnal predators and are rarely seen during the day. The Wolf Spider has incredible night vision. If you shine a flashlight in the dark, you may see their green eye shine. It’s caused by a tapetum in the eye which reflects light rays back through the eye retina.

Now, while Wolf Spiders are common in the desert southwest and look scary, they are actually quite harmless.

But, that doesn’t mean they won’t bite when disturbed or habitat compromised. While this desert spider’s bite contains no venom, it can be extremely painful.

When they do bite, they actually will tear the skin. Your most serious concern should be secondary infections and lymph node swelling and pain.

On a good note, wolf spiders are actually a beneficial part of the food chain and are a positive for controlling more dangerous pests.

That said, don’t instigate or threaten them or their habitat, bring them inside your RV or vehicle nor transport them to other states or regions.

Desert Brown Recluse Spider

Brown Recluse Spider

There is nothing cute about the Desert Brown Recluse Spider. It’s identified by it’s notorious violin shape on it’s back.

The Desert Brown Recluse Spider isn’t one to be basking in the hot desert sun. Hence, why it’s called the Recluse is because it prefers to hide in dark places. These desert arachnids are attracted to brown paper bags and cardboard, so make certain you don’t leave boxes outside; even for an overnight.

Speaking from experience, I recommend never leave shoes, gloves or jackets outside. And, make sure you thoroughly shake out and inspect any blankets, towels and clothing before bringing them inside.

Desert Brown Recluses are known to hitchhike so, before packing up to leave your campsite, pay attention to your outdoor campsite mat, camp chairs, tables, grill and even your fire pit.

Also, check your RV basement compartments. Be very careful when picking through piles of firewood, desert brush and dead cactus’ plants. Don’t allow your dog to nose around in brush piles, around rock crevices, et.c

Though this desert spider is small, it’s venomous bite is highly toxic. In fact, the Desert Brown Recluse is amongst the deadliest spiders in the world!

Victims usually experience swelling of the bite sight, aches and fatigue. Should you get bit by one of these nasty biters, keep a close eye on the bite sight. Necrosis will set in and cause permanent tissue damage. So, it’s imperative that you or the victim seek medical attention immediately.

Arizona Brown Spider

There are five species of the Arizona Brown Spider that are venomous. These little desert spiders are quite small; measuring in no more than 1/2″ in length.

They range in different shades of brown, have that distinctive violin shape on its’ cephalothorax pointing away from its’ head. The Arizona Brown Spider also has 3 sets of eyes!

This little desert spider loves to take up residence in wood piles, cinder block walls, attics, and packrat nests. They will also hitchhike onto any clothing, blankets, bedding or anything left outside or even in your RV’s exterior compartments.

So, like the Desert Brown Recluse, make certain not to bring them into your RV or vehicle.

When they bite, you may notice fang marks. The bite side may redden and feel warm to touch. Within a few hours, a red ring will appear; much like a bull’s eye. Soon, a lesion or sore will appear and necrosis will set in.

Should you get bit by the Arizona Brown Spider, it’s best to seek medical attention immediately; especially if you experience allergic reactions to insect and spider bites.

Black Widow Spider

Just when you thought you only should only worry about brown spiders, the female Black Widow Spider packs a far worse punch when she bites.

It comes as no surprise that she’s the most venomous spider on the continent. Also known as the Western Black Widow, this venomous desert spider’s bite is 15 times more toxic as the Prairie Rattlesnake.

The adult female Black Widow is usually twice the size of her male counterpart (about 1/4″ to 3/4″ in body length – not including her legs). She’s either a glossy black or very dark brown.

And, not that you’re going to chance flipping her over, she can be easily spotted because of her very large rounded abdomen with her dead giveaway red hourglass shape on her belly.

Black Widow males, as mentioned above, are half the size of the females. But, they are typically a medium brown with vanilla colored markings on his legs and abdomen.

Black Widow babies and young look much like the male. Neither male or juvenile Black Widow spiders bite humans. Their mouths are not large or strong enough to inject venom should they try to bite.

According to National Geographic’s article, How Male Widow Spiders Avoid Bing Cannibilized During Sex, “mating is an infamously dangerous activity. In these species, which include the black widow and redback, the large females will often devour the smaller males during sex; hence the “widow” in their names.”

When she’s not mating, the Black Widow spins a web to trap her prey. Notably though, Black Widow spider webs are much stronger and non-symmetrical; unlike other web weavers’.

Black Widow Spiders are also nocturnal. They avoid confrontation, are actually docile and shy. So, they’ll only bite when antagonized or threatened.

According to the Arizona-Sonora Desert Museum, “The black widow is one of two species within our region that is potentially dangerous to humans (the brown spider is the other). The bite can kill a human, but this is rare. More often, the bite is painful and causes serious reactions, including nausea, dizziness and abdominal cramps.”

So, it’s important to seek immediate medical attention soon after being bit by a Black Widow spider.

How to prevent desert spider infestations

Desert Spider Nest

Spider infestations can happen; especially while you’re in the desert southwest for any long period of time. But there are things you can do as an RV or camper to alleviate chances of any of these dangerous desert spiders taking refuge in your RV or vehicle.

- Most spiders despise certain strong odors. You can try mitigating spider infestations using potent therapeutic grade essential oils such as Tea Tree, Peppermint, Eucalyptus and those in the Citrus families.
- Do not store paper bags, folded cartons or keep boxes. If you need to store contents in your RV exterior storage compartments, use plastic totes with lids.
- Keep your RV interior and compartments clean and free of dust, dirt and pilings of debris that small animals may bring in. Do not store firewood in your RV.
- Don’t park your RV or vehicle(s) near shrubs or low hanging tree limbs.
- Keep a close eye under the hood and trunks where spiders can make nests.
- Wear gloves when reaching into your fifth wheel pin box.
- Repair any holes in your RV screens, seal and plug any holes where spiders may access. Keep vents covered when you’re not using. And, inspect all of those often. If you see any webs or nests, get rid of them immediately. You may have to hire a professional exterminator should you find an infestation inside your RV or vehicle.

But, while you’re camping, whether it’s boondocking out in the desert or at a campground with hookups, you still need to be aware that desert spiders may be lurking at your campsite or the campground itself.

- Always check before reaching for anything such as power pedestals, small brush piles, rock gardens, etc.
- Before sitting at picnic tables, benches or chairs, always inspect underneath, in cracks and crevices.
- Check laundry rooms. If you drop a piece of clothing on the floor, shake it out vigorously.
- Wear gloves when picking up anything off the ground such as your sewer hose and attachments.

Final thoughts on desert spiders to avoid in the Southwest

WHEW! This was one of the most difficult articles I’ve ever written because of my fear of those 8-legged tiny monsters.

But, I hope this information doesn’t deter you from exploring the desert southwest. Spiders are very much part of the ecological environment. They are much needed link in the food chain.

Like all wildlife, desert spiders should be respected and left alone to live out their lives in their desert habitats. Learn to coexist with them even though they look scary or may harm if antagonized or threatened. The best advice is to just stay clear of any desert spiders.

♦ PRO TIP ♦ If you’re headed out to the deserts in the Southwestern United States, you should familiarize yourself with spiders that live in the desert. Check out this spider identification chart.