Are Woodlouse Spiders Poisonous? The Truth Behind These Critters

Are woodlouse spiders poisonous? It’s a question that many people might have, especially if they come across one of these arachnids in their home or garden.

The short answer is no, woodlouse spiders (Dysdera crocata) are not considered to be poisonous to humans. But there’s more to the story than just a simple yes or no answer.

In this article, we’ll take a closer look at woodlouse spiders and their venom, and examine whether their bite is harmful to humans.

We’ll also discuss where woodlouse spiders live, what they eat, and how to get rid of them. and explore why these spiders might actually be beneficial to have around.

So if you’re curious about woodlouse spiders and their potential danger (or lack thereof), keep reading!

What are Woodlouse Spiders?

Woodlouse spiders, also known as Dysdera crocata, are a type of spider that is commonly found in the United States.

They are known for their unique appearance, which can make them easily recognizable. These spiders have reddish-orange legs and bodies, with a dirty white abdomen that resembles a bean in shape.

When it comes to size, there is a noticeable difference between male and female woodlouse spiders.

Male spiders are smaller, measuring between 0.3 to 0.4 inches in length, while females are larger, reaching between 1.1 to 1.5cm in length or 0.4 to 0.5 inches long.

Woodlouse Spider (Clint’s Reptiles)

Identifying a woodlouse spider can be done by its physical features, such as its body shape and coloring.

It is important to note that while woodlouse spiders may look similar to other spider species, their unique coloration and body shape can help differentiate them.

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Difference Between Woodlouse Spiders and Brown Recluse Spiders

Many people may confuse woodlouse spiders with brown recluse spiders due to their similar appearance.

However, there are distinct differences between the two species.

Difference Between Woodlouse Spiders and Brown Recluse Spiders

Brown recluse spiders have a distinct violin-shaped marking on their backs, while woodlouse spiders have a solid gray back.

Woodlouse spiders also have reddish-brown heads and legs, while brown recluse spiders are a more uniform brown color.

Additionally, woodlouse spiders have distinct jaws that jut forward, whereas brown recluse spiders have a dark brown violin shape on the cephalothorax and an eye pattern of 6 eyes in pairs with a space separating the pairs.

Other spiders, such as Southern house spiders, Arizona black hole spiders, giant house spiders, and barn funnel weavers, may also look similar to brown recluse spiders. 

However, they can be distinguished by their body proportions and eye patterns.
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Where Do Woodlouse Spiders Live?

Woodlouse spiders are primarily found in the eastern United States, although their range extends as far west as Arizona.

These spiders are typically found in moist environments such as under rocks, logs, and other debris on the forest floor.

They are also known to inhabit basements and crawl spaces in homes and buildings.

In natural settings, woodlouse spiders are often found in deciduous forests, where the leaves provide cover and the soil retains moisture.

They are also commonly found in gardens and parks, where there is ample debris and foliage to provide hiding places and prey.

While woodlouse spiders prefer humid environments, they are capable of surviving in drier areas as well.

In fact, they are often found in desert regions of the southwestern United States.

These spiders are nocturnal and are rarely seen during the day, preferring to hunt and move about under cover of darkness.

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How Long Do Woodlouse Spiders Live?

Woodlouse spiders typically have a lifespan of about two to three years, from hatching to death.

However, their lifespan can vary depending on various factors such as habitat conditions, food availability, and predators.

Male woodlouse spiders typically have a shorter lifespan compared to females as they mature faster and die shortly after mating.

Females, on the other hand, can live longer as they have to guard and care for their eggs until they hatch.

It’s important to note that the lifespan of woodlouse spiders can also be affected by human activities, such as pesticide use and habitat destruction.

In areas with heavy pesticide use or the destruction of natural habitats, the population of woodlouse spiders can decline, leading to a shorter lifespan.

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What Do Woodlouse Spiders Do?

Woodlouse spiders are predators and play an important role in controlling populations of other insects and arthropods.

They are particularly skilled at catching woodlice, which is their primary food source, but they will also eat other insects, including beetles and moths.

Woodlouse Spider Hunting (Ian Phillips)

Woodlouse spiders are active hunters and will actively seek out their prey. They do not use webs to catch their prey, but will instead use their speed and agility to chase down and capture their meals.

They are particularly effective at hunting in small spaces, like cracks and crevices, where their prey may be hiding.

In addition to their role as predators, woodlouse spiders also play an important role in their ecosystem as prey for other animals.

Birds, small mammals, and other spiders may all feed on woodlouse spiders, helping to maintain a balanced ecosystem.

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What Do Woodlouse Spiders Eat?

As mentioned above woodlouse spiders are primarily carnivorous and feed on a variety of insects, including woodlice, beetles, and other spiders.

They are known to be active hunters and will often chase and capture their prey.

The hunt, The feed, The amazing Dysdera crocata (Mark’s Tarantulas)

In addition to insects, woodlouse spiders have also been known to eat other arachnids, such as harvestmen and pillbugs.

They are also known to cannibalize other woodlouse spiders if they are in need of food.

Woodlouse spiders are known to have a venomous bite, which they use to immobilize their prey.

They have been observed injecting venom into their prey, which paralyzes them and makes it easier for the spider to consume them.

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How Do Woodlouse Spiders Reproduce?

Woodlouse spiders reproduce by mating, which is typically an aggressive process. During mating, the male and female spiders risk injury from each other’s large chelicerae.

After mating, the female spider lays her eggs in a silken sac, which can contain up to 70 eggs.

Once the eggs hatch, the female spider is believed to take care of her young. This behavior is not commonly observed in spiders, as most spider species do not provide any parental care for their offspring.

However, woodlouse spiders are known to exhibit this maternal behavior.

Woodlouse spider hatching (Jeneen Crawford)

The eggs of woodlouse spiders typically hatch within a few weeks to a few months, depending on the temperature and other environmental factors.

After hatching, the spiderlings will undergo several molts as they grow and develop into mature spiders.

It is worth noting that not much is known about the reproduction and life cycle of woodlouse spiders, as they are not a well-studied species. 

However, based on available research and observations, it is believed that woodlouse spiders exhibit similar reproductive behavior and life cycles to other spider species.
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Are Woodlouse Spiders Poisonous?

are woodlouse spiders poisonous

Woodlouse spiders are not considered poisonous to humans. Their venom is harmless to most people, and their bites can only cause pain and swelling due to their large fangs.

Although it is possible for some people to have an allergic reaction to the venom, the bites are not generally dangerous, and most people do not require medical treatment.

As for pets, there is little research on the effects of woodlouse spider bites on dogs and cats.

However, it is generally recommended to keep pets away from spiders to prevent bites and potential allergic reactions.

If you suspect your pet has been bitten, it is best to consult with a veterinarian for proper treatment.

If you are bitten by a woodlouse spider, you can treat the bite by washing the area with soap and water, applying a cold compress to reduce swelling, and taking over-the-counter pain medication as needed.

If you experience severe pain, swelling, or other unusual symptoms, it is best to seek medical attention to rule out the possibility of an allergic reaction or other complications.
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Why Woodlouse Spiders May be Found in Homes

Woodlouse spiders may be found in homes for a variety of reasons.

Firstly, they are attracted to damp and dark environments, so if a home has areas with high humidity or moisture levels, such as basements, bathrooms, or kitchens, they may seek shelter there.

Woodlouse Spider A common spider found in your garden (Heirloom Reviews)

And woodlouse spiders are often found in homes that are situated in wooded areas or near forests, as they may accidentally make their way inside.

Woodlouse spiders may also enter homes in search of prey. They feed on insects, including woodlice, which are common in homes with gardens or outdoor areas.

If there are cracks or holes in a home’s foundation, walls, or doors, woodlouse spiders may use these entry points to gain access to the home.

Also, woodlouse spiders may be found in beds due to their nocturnal behavior.

They are active at night and may accidentally find their way into a bed, especially if the bed is located in an area where woodlouse spiders are commonly found, such as a basement or a ground-floor bedroom.

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if their presence becomes problematic or if homeowners are uncomfortable with sharing their living space with woodlouse spiders, there are ways to safely and humanely remove them.

How to Get Rid of Woodlouse Spiders?

There are several methods to get rid of woodlouse spiders from your home. Here are some options.

are woodlouse spiders poisonous?How to Get Rid of Woodlouse Spiders?

Keep your home clean and tidy

Keeping your home clean and tidy is one of the most effective ways to prevent woodlouse spiders from entering and establishing themselves in your home.

This means vacuuming regularly to remove any webs or eggs, dusting and wiping down surfaces, and keeping clutter to a minimum.

It’s also important to take out the trash regularly and to seal any cracks or gaps around windows and doors to prevent spiders from entering.

If you have any outdoor plants or firewood, be sure to keep them a good distance from your home, as spiders may use them as a hiding spot before making their way inside.

Regular cleaning and maintenance can also help to deter other household pests that woodlouse spiders may prey on, reducing their food sources and making your home a less attractive place for them to stay.

Use spider repellents

Another method to get rid of woodlouse spiders is to use spider repellents. There are various types of spider repellents available on the market, including sprays, ultrasonic devices, and essential oils.

Sprays can be used to directly target spiders in areas where they are commonly found, such as corners and crevices.

Ultrasonic devices emit high-frequency sound waves that are unpleasant to spiders and can help keep them away from the treated area.

Essential oils such as peppermint, tea tree, and eucalyptus oil can also be used to repel spiders, either by diluting and spraying the oil or by placing cotton balls soaked in the oil in areas where spiders are commonly found.

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Seal cracks and gaps

To effectively eliminate woodlouse spiders, it is recommended to seal any cracks or gaps in and around your home.

These spiders can easily make their way into your living spaces through small openings, so sealing gaps in walls, doors, and windows can prevent their entry.

caulk or weatherstripping to seal gaps, and ensure that any damaged window or door screens are repaired.

This will not only keep woodlouse spiders out, but also prevent other unwanted pests such as ants, cockroaches, and mice from entering your home.

Remove their food source

Another effective method to get rid of woodlouse spiders is to remove their food source.

These spiders primarily feed on woodlice, so eliminating woodlice from your home and garden can help to deter woodlouse spiders.

To remove woodlice from your home, you can use a vacuum cleaner to suck them up or use sticky traps to catch them.

In the garden, removing damp and decaying wood and debris can help to reduce the woodlouse population.

By eliminating the woodlice that woodlouse spiders feed on, you can make your home and garden less appealing to these spiders and reduce their presence.

Professional pest control

If the woodlouse spider infestation is severe or other methods do not work, professional pest control may be necessary.

A pest control professional can assess the situation and determine the most effective treatment plan. They may use insecticides or other specialized methods to eliminate the spiders and prevent them from returning.

It’s essential to choose a reputable pest control company that uses safe and effective methods.

Additionally, it’s important to follow their instructions and recommendations for preventing future infestations.

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Common Misconceptions about Woodlouse Spiders

There are several misconceptions about woodlouse spiders that are worth clarifying. Here are some of the most common ones:

Woodlouse spiders are dangerous and venomous

As we mentioned earlier, woodlouse spiders are not dangerous to humans. Their venom is harmless to most people, and while their bites can be painful, they are generally not dangerous.

Woodlouse spiders are a type of brown recluse spider

This is not true. While woodlouse spiders may resemble brown recluse spiders in appearance, they are a completely different species.

Woodlouse spiders are attracted to damp environments

While woodlouse spiders do prefer moist environments, they are not exclusively found in damp areas. They can also be found in dry areas such as attics and closets.

Woodlouse spiders are commonly found in beds

While it is possible for woodlouse spiders to end up in beds, it is not a common occurrence. They are more likely to be found in dark, secluded areas where they can hunt for their preferred prey.

Woodlouse spiders are difficult to get rid of

While woodlouse spiders can be persistent, they are not impossible to get rid of. By following the methods we outlined earlier, such as keeping your home clean and tidy, sealing cracks and gaps, and using spider repellents, you can effectively prevent and control woodlouse spider infestations.

So It is important to have accurate information about woodlouse spiders so that you can take appropriate measures to prevent and control infestations.
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Final Thoughts

Woodlouse spiders are not poisonous to humans or pets, including dogs and cats. While their bites can be painful due to their large fangs, the venom is generally harmless to most people.

It is important to understand the facts and dispel any common misconceptions about woodlouse spiders.

If you do encounter these spiders in your home, there are several effective methods for controlling their presence, including keeping your home clean and tidy, using spider repellents, sealing cracks and gaps, removing their food source, and seeking professional pest control if necessary.

By following these tips, you can help prevent woodlouse spiders from becoming a nuisance in your home. Remember, just because they look scary, it doesn’t mean they are dangerous.


What attracts woodlouse spiders?

Woodlouse spiders are attracted to areas where they can find prey, such as other insects. They are also known to prefer humid environments and can be found in outdoor locations such as under rocks or in leaf litter.

Why is there a woodlouse in my bed?

It’s possible that a woodlouse spider crawled into your bed seeking shelter or chasing after prey. They are nocturnal hunters and can move quickly, so it’s not uncommon to find them in unexpected places.

What happens if a woodlouse spider bites you?

Woodlouse spiders are not considered dangerous to humans, and their bites are generally mild and similar to a bee sting. Symptoms may include redness, swelling, and itching, but these typically subside within a few hours.

Are woodlouse spiders poisonous to dogs & cats?

Woodlouse spiders are not considered poisonous to dogs or cats, but ingestion could potentially cause an upset stomach. It is best to monitor your pets around any insects or spiders and seek veterinary help if necessary.

Where did the woodlouse spider come from?

Woodlouse spiders are native to Europe but have been introduced to other parts of the world, including North America.

Are woodlouse spiders nocturnal?

Yes, woodlouse spiders are nocturnal and are most active at night.

What are woodlouse spider predators?

Woodlouse spiders have several natural predators, including birds, lizards, other spiders, and some insects.

What is the prey of a woodlouse spider?

As their name suggests, woodlouse spiders primarily feed on woodlice, but they may also eat other small insects such as silverfish and beetles.

Resources – (for further reading)

British Arachnological Society – Summary for Dysdera crocata (Araneae)

Wikipedia – Woodlouse spider

Utah State University – Woodlouse Spider – School IPM

I'm Ernest M Noah, the founder of I have years of experience as an exterminator in Texas and Idaho, and I'm passionate about educating people on how to deal with pest problems effectively and safely.