Are Woodlouse Spiders Venomous?


The Woodlouse spider (Dysdera crocata) is a spider species that mainly hunts and feeds on woodlice and is mostly found in Africa, Asia, Eurasia, Europe, North America, Oceania, and South America.

A creature with sharp fangs that can pierce through tough armour. These nocturnal hunters are easy to spot with their reddish-brown bodies and long, funny-looking mouthparts.

But before you consider letting one share your space with them, there is an important question: Are woodlouse spiders venomous or dangerous to humans?

Woodlouse spiders do have venom, but it is not meant for us. Their venom is designed to dissolve the insides of woodlice, their favourite prey.

They rarely bite humans, as they are more interested in chasing woodlice than bothering us.

And even if you do get bitten, do not worry – their venom won’t harm you. At most, you might feel a little irritation or swelling, similar to a mosquito bite.

Join us as we take a closer look into the captivating world of woodlouse spiders to learn more about their venom and bite, unique hunting methods, behavior, and whether you should ever consider having one as a pet. Let’s have a look…!

Interesting Facts About Woodlouse Spiders:

  • They do not spin webs; instead, they are agile hunters stalking woodlice using their keen senses.
  • Large fangs are adapted for piercing woodlice exoskeletons, delivering potent venom.
  • Despite the intimidating name, their primary focus is on woodlice, posing little threat to humans.
  • Bites are rare and occur only when they feel threatened.
  • Shed skin multiple times a year, growing larger with each molt.
  • Bodies can flatten, allowing them to navigate through tiny cracks.
  • They serve as prey for various creatures, helping maintain ecosystem balance.
  • Crucial in controlling woodlice populations, reducing the need for chemical pesticides.
  • Consume the entire woodlouse, contributing to decomposition and nutrient cycling.
  • Woodlouse spiders are solitary creatures, except for during mating.
  • They are primarily nocturnal hunters, lurking in the shadows for their unsuspecting prey.
  • Though their venom is potent against woodlice, it is harmless to humans unless you have a severe allergy.

Woodlouse Spider: A Brief Introduction:

The woodlouse spider has other common names, such as woodlouse hunter, sowbug hunter, sowbug killer, pillbug hunter, and slater spider, and is scientifically known as Dysdera crocata.

According to research, woodlouse spiders have more than five hundred species. Some of the additional members of the Dysderidae family include Dysdera verneaui, Dysdera erythina, Dysdera aurgitana, and Dysdera ancora.

Woodlouse Spider Close Up

Woodlouse spiders usually come in shades of light brown to dark grey. Female woodlouse spiders are bigger than males.

Females measure between 11 to 15 mm in body length, while males are slightly smaller, ranging from 9 to 10 mm.

While woodlice are their primary prey, woodlouse spiders occasionally diversify their diet by consuming other small invertebrates, including silverfish, earwigs, millipedes, and, in rare cases, even small crickets.

Woodlouse hunters, or woodlouse spiders, can be found in various places as long as their essential needs are met.

They prefer damp environments, thriving in places like basements, cellars, under rocks, and damp leaf litter, including spots inside homes near leaky pipes.

While they may sometimes end up inside houses, they usually favor damp locations such as basements. Gardens with shade and moisture.

Being nocturnal hunters, they seek out dark corners and crevices for shelter, creating silken retreats as bases for hunting and protection.

The lifespan of these spiders spans 2-3 years, influenced by environmental factors such as temperature, humidity, and prey availability, with females typically outliving males.

How to Identify Woodlouse Spiders?

Woodlouse spiders are occasionally confused with brown recluse spiders due to their similar color and size.

Despite similarities in size, color, leg count, and habitat, distinguishing features include the arrangement of eyes (triads in woodlouse spiders, dyads in brown recluses), markings (absence of a violin-shaped mark on the cephalothorax in woodlouse spiders), and physical attributes (fine hairs on woodlouse spiders’ legs versus smooth legs on brown recluses).

Additionally, their web-building behavior and activity patterns differ, with woodlouse spiders being nocturnal hunters and brown recluses exhibiting more daytime activity.

While both spiders are capable of biting humans, it’s crucial to note that the venom of a brown recluse is more potent and has the potential to result in severe health complications.

Understanding these distinctions is crucial for accurate identification and appropriate precautions.

Are Woodlouse Spiders Venomous?

From a technical standpoint, yes, woodlouse spiders venomous are venomous. Similar to most spiders, woodlouse spiders possess specialized venom-producing glands crucial for subduing their primary prey, i.e., woodlice.

The venom efficiently breaks down the insides of woodlice, serving as a nutritious meal for the spider.

Woodlouse Spider Anatomy and Venom with Respect to Bite:

The woodlouse spider might look scary, but it’s not much of a threat to people. Let’s break down its features: big fangs for piercing woodlice, eight eyes for good vision, a shiny abdomen with venom glands, and long legs for moving around and hunting.

Its venom mainly targets the nervous system of its prey, like woodlice, but for humans, it is not that strong, just causing some pain, swelling, and itching.

The spider usually does not bite people on purpose and prefers to run away when bothered.

If it does accidentally bite, it is like getting a mosquito bite with minor pain and swelling, and there have not been any serious health issues reported from these bites.

How Woodlouse Spiders Hunt Their Prey and Inject Venom?

They are active hunters, especially after woodlice. These spiders rely on their sharp senses of smell and touch to quietly approach their prey in the dark.

When close, they swiftly pounce, using their scissor-like fangs to pierce woodlice shells and inject venom that turns the insides into a tasty meal.

After the feast, the spider patiently waits for the venom to work its magic, then carefully cleans up, leaving behind an empty shell.

This web-less strategy offers advantages, letting them navigate tight spaces, hunt efficiently, and stay less conspicuous in their damp habitats.

So, while they may not weave fancy webs, woodlouse spiders showcase unique hunting skills and resourceful silk use in their cozy shelters.

Is Woodlouse Spider Venom Harmful to Humans?

However, when it comes to causing harm to humans, the answer is no, not to a significant extent.

The potent venom that works on woodlice is generally not strong enough to pose a threat to humans unless there is a severe allergy.

In most cases, a woodlouse spider bite results in mild, localized symptoms like minor pain, swelling, and itching, similar to an insect bite, and these symptoms typically resolve on their own within a few days.

It is essential to understand that while woodlouse spiders are technically venomous, the risk to humans is minimal, especially when compared to spiders with more potent venom, like the black widow.

Respecting spiders, avoiding unnecessary contact, and recognizing their ecological role can help prevent bites and promote peaceful coexistence.

If there are concerns about spider bites or venom, consulting a healthcare professional for personalized advice is recommended.

Do Woodlouse Spiders bite?

Yes, woodlouse spiders can bite, but the likelihood and consequences are often exaggerated.

Why would they bite?

Woodlouse spiders are not aggressive towards humans; they are focused on hunting woodlice.

Bites occur rarely, usually when the spider feels threatened or cornered, such as accidental contact while gardening, mistaken identity in poor lighting, or extreme confinement.

What happens if they bite? Symptoms?

Most woodlouse spider bites are mild, causing a small red bump, mild pain, itching, or swelling. Severe reactions to woodlouse spider bites are uncommon unless you have a strong allergy to spider venom.

If you notice rapid spreading redness, intense pain, difficulty breathing, nausea, or dizziness, seek immediate medical attention.

Woodlouse Spider bite and  Symptoms

What is the Treatment If a Woodlouse Spider Bites You?

If you experience a suspected woodlouse spider bite, clean the area with soap and water and monitor for any worsening symptoms. Seek medical attention if redness, swelling, or pain intensifies.

How to Avoid Their Bites?

  • Avoid handling woodlouse spiders.
  • Wear gloves in areas where these spiders might be present.
  • Be cautious to avoid accidental crushing.
  • Respect their space and observe from a safe distance.
  • Remember:
  • Woodlouse spiders are beneficial for controlling woodlice.
  • Bites are extremely rare and typically mild.
  • Panicking or harming the spider is unnecessary and may provoke a bite.
  • Seek medical attention for unusual or concerning symptoms.

By understanding their behavior and respecting their space, coexisting with these fascinating creatures can be safe. I hope this information clarifies the myths and realities surrounding woodlouse spider bites.

Read Also: What Does Wolf Spiders Eat?

Can You Keep a Woodlouse Spider as a pet?

Keeping woodlouse spiders as pets is not advised due to practical challenges and potential risks.

They mainly eat woodlice, but it can be challenging to obtain them ethically. Creating their preferred habitat in captivity is complex, and they may bite if stressed.

Providing the necessary care, such as maintaining the right humidity and temperature, can be difficult for inexperienced owners.

Safer spider species with simpler care requirements are recommended for observation.

Removing them from their habitat can disrupt ecosystems, and wild-caught spiders may carry diseases.

Overall, appreciating woodlouse spiders in their natural setting is preferable for responsible pet ownership.

How to Get Rid of Woodlouse Spiders?

The woodlouse spider relies significantly on woodlice as a part of its diet. Consequently, eliminating woodlice can be an effective strategy to decrease the presence of woodlouse spiders within a house.

The key to getting rid of woodlice involves eliminating the environments they favor. This includes removing decaying wood from a home’s structure and relocating woodpiles away from patios and house walls.

Any areas characterized by dampness and darkness serve as attractive habitats for both woodlice and woodlouse spiders.

To prevent woodlouse spiders from entering, it is beneficial to seal cracks and crevices in a home’s brick walls.

By addressing the factors that attract woodlice, a less conducive environment is created for woodlouse spiders, leading to their reduction in and around the house.

Ecological Importance:

Woodlouse spiders, despite their predatory nature, are ecological superheroes. Their primary role lies in natural pest control, targeting woodlice that can be nuisances in various settings.

By keeping woodlice in check, they indirectly support healthy gardens, improve agricultural yields, and reduce the need for chemical pesticides.

Beyond pest control, these spiders reduce pesticide use, contribute to decomposition, and play essential roles in nutrient cycling.

In essence, woodlouse spiders, with their fearsome appearance, emerge as valuable guardians, ensuring the well-being and stability of ecosystems.


The woodlouse spiders, while becoming venomous, poses minimal harm to humans. Human bites are rare, and symptoms are typically mild.

Understanding and respecting these spiders can promote coexistence, emphasizing their vital role in controlling woodlice populations and contributing to ecosystem balance.


Is a woodlouse spider poisonous?

Yes, woodlouse spiders are technically venomous. They use their venom to subdue their prey, primarily woodlice. But their venom is harmless to humans.

Are woodlouse spiders dangerous?

No, their venom is not strong enough to harm humans significantly unless you have a severe allergy. Bites are rare and typically cause only mild, localized symptoms like pain, swelling, and itching, which resolve on their own.

Do woodlice spiders bite?

Yes, they can bite in rare cases if they feel threatened or cornered.

Woodlouse spider bite symptoms?

Woodlouse spider bite symptoms are usually mild, like redness, swelling, and itching around the bite site. These resolve within a few hours or days.

Do woodlouse spiders bite cats and dogs?

While they can bite cats and dogs, their venom is unlikely to harm them either. Consult a veterinarian if you notice any concerning symptoms in your pet.

Woodlouse spider bite treatment?

For mild bites, no treatment is usually necessary. If you experience severe symptoms or have an allergy, seek medical attention.

Are woodlouse spiders poisonous to pets?

No, their venom is not poisonous to most pets. However, observe your pet for any abnormal behavior or symptoms after interaction with a woodlouse spider.

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