Don't Be Afraid of the Big, Bad Wolf Spider

wolf spider, egg sac — Female wolf spiders carry their egg sacs around with them to protect the unborn babies from parasites and predators. Nancy Hinkle/Dept. of Entomology/UGA

Key Takeaways

Wolf spiders are large, agile hunters found worldwide, with over 2,300 species known for their excellent vision and lack of webs.
These spiders are harmless to humans and beneficial as they help control pest insect populations in homes and gardens.
Female wolf spiders carry their egg sacs and later their spiderlings on their backs, offering protection until the young are ready to survive on their own.

Some people are afraid of spiders — maybe even you. It's not uncommon, and scientists aren't completely sure whether arachnophobia is hardwired into us, or whether we learn it along the way. But when you hop in the shower and are immediately confronted with the spindly spread of eight hairy legs, it's hard not to give a hop right back out.

And sometimes when you bring somebody into the bathroom to help remove the spider, they'll say, "Oh, that's just a wolf spider — nothing to worry about!" Or else they'll say, "Oh no, it's a wolf spider — let's both commence freaking out!"

It's possible your friend is right about it being a wolf spider, because in many parts of the world, in the center of the Venn diagram of spiders that are large and occasionally in your shower, you'll find this majestic creature.

Of course, saying something is a wolf spider isn't all that specific — there are 100 genera, or families, and over 2,300 species of wolf spiders in the world, over 238 of which occupy different habitats and regions of the United States. They're usually well-camouflaged: dark-colored with a (usually striped or banded) pattern of black, brown, gray or tan markings on their backs and legs. Depending on the species, they can range in size from reasonable (a quarter of an inch [6.5 mm]) to what some would call unreasonable (over an inch [3 cm]). The females are always larger than the males and carry their egg sacs around with them to protect the unborn babies from parasites and predators. Once the spiderlings emerge, they ride around on their mom's back until they are large enough to make it on their own.

Are Wolf Spiders Dangerous to Humans?

While these robust spiders can be alarming houseguests, none of the thousands of species are dangerous to humans.

"Wolf spider are harmless and, indeed, provide valuable pest control around our homes and yards because they eat pest insects," says Nancy Hinkle, a professor in the Department of Entomology at the University of Georgia. "As might be guessed from their name, wolf spiders are hunters and stalk their prey. They have large eyes, giving them exceptional vision and allowing them to spy prey and successfully pursue it."

In fact, these athletic spiders are such strong hunters they don't even need to build webs in order to snag a meal. They spend their nights stalking around after their quarry, and occasionally find their way into your house:

"Because spiders feed on insects, they seek out places where insects congregate," says Hinkle. "Think about the numbers of insects that show up at your porch light; spiders view this as a buffet. To reduce the chance of spiders slipping under the door, turn off the porch light to avoid luring insects to your door."

Out of doors, wolf spiders build holes or tunnels in the ground or live in little protected areas between rocks, in cracks in old stumps, etc. — wherever it looks safe and dry. In fact, according to Hinkle, if you find a large spider inside your house, it's likely there's some opening large enough for a spider to squeeze in — a space under a door, a pipe chase, a hole in the wall where a cable line enters the floor from a crawlspace.

"If a spider is big enough to enter, it's likely a lot of heated or air-conditioned air is escaping through the same hole," says Hinkle. "If you're finding a lot of spiders in your home, it's probably worth using your detective skills to locate any cracks or gaps, seal them up, and save energy while excluding spiders."

But if you do find a wolf spider in your house, the best idea is to take a deep breath and remember, this arachnid's on your team, ridding your house of unwanted insects. There is virtually no chance this spider will come at you — they will bite if handled or trapped next to your skin, but it's unlikely you'd have much of a reaction to the bite. But remember, they will always choose retreat from a human that's thousands of times larger with opposable thumbs and a rolled-up newspaper.

"Because they are harmless to humans, spiders found in the home should be relocated outdoors," says Hinkle. "To do this, place a jar over the spider, slide a stiff piece of paper under the jar, and carefully carry it outside for release."

Learn more about spiders in "Spiders: Amazing Pictures & Fun Facts on Animals in Nature (Our Amazing World Series)" by Kay de Silva. HowStuffWorks picks related titles based on books we think you'll like. Should you choose to buy one, we'll receive a portion of the sale.

Frequently Asked Questions

How do wolf spiders hunt if they don't build webs?

Wolf spiders are active hunters, relying on their excellent vision and speed to stalk and pounce on prey. They use their large eyes to detect movement and hunt primarily at night, often capturing insects and other small arthropods directly on the ground.

Why do female wolf spiders carry their egg sacs and spiderlings?

Female wolf spiders carry their egg sacs attached to their spinnerets to protect the eggs from predators and parasites. After the spiderlings hatch, they ride on the mother's back for several weeks until they are mature enough to survive on their own, ensuring a higher survival rate for the young spiders.