Are Trapdoor Spiders Poisonous? Unveiling the Truth

Trapdoor spiders, a group of spiders found across the world, are notorious for their unique hunting technique.

They construct burrows with hinged doors, lying in wait for their prey, and fiercely lunging when the opportunity strikes.

This fascinating behavior sparks curiosity about the potential danger of these spiders to humans.

Are Trapdoor Spiders Poisonous
Male Trapdoor Spider

While trapdoor spiders are venomous, as they use their venom to paralyze and immobilize prey, they typically don’t present a significant threat to humans.

The potency of their venom varies between species, but generally, their bites cause mild discomfort and localized pain.

It’s important to know the specifics of the species you encounter to better understand the risks involved.

For example, the Sydney funnel-web spider, a relative of trapdoor spiders, has a venom that can be life-threatening to humans.

On the other hand, North American trapdoor spiders like Ummidia audouini possess venom that is of minimal concern, causing slight itchiness or irritation.

Educating yourself about the differences in toxicity levels can help alleviate fears and ensure your safety around these fascinating creatures.

Are Trapdoor Spiders Poisonous?

Venom Composition

Trapdoor spiders, like most spiders, are venomous.

Their venom is composed of various proteins and peptides, which can affect the nervous system of their prey.

However, the venom’s potency varies depending on the species of trapdoor spider.

Effects on Humans

Although trapdoor spiders are venomous, their bites are generally not considered dangerous to humans.

According to the North Carolina Museum of Natural Sciences, a bite from a trapdoor spider will not cause a human to die within five minutes.

Trapdoor Spider

Moreover, Cyclocosmia spiders, a type of trapdoor spider, are not poisonous to humans.

  • Some symptoms of a trapdoor spider bite include:

    • Pain and swelling at the bite site
    • Redness
    • Itching

In comparison to other spiders, trapdoor spiders are less likely to cause severe reactions in humans.

However, individual reactions may vary, and some people may experience more severe symptoms.

It is essential to seek medical attention if you suspect a spider bite and experience significant pain or adverse reactions.

Trapdoor Spiders Overview

Species and Distribution

Trapdoor spiders belong to the family Ctenizidae, with Ummidia being the most speciose genus, comprising about 50 species1.

They are mainly found in the United States, particularly in the eastern and southwestern regions, extending north to Colorado1.

Physical Characteristics

  • Body size: Medium to large
  • Color: Typically brown or black
  • Modified front legs: Used for digging burrows
  • Silk-lined burrows: With a camouflaged, hinged trapdoor1

Trapdoor spiders are not known for being venomous or posing significant threats to humans2.

Trapdoor Spider

They are primarily ambush predators, catching prey from their burrows1.

Some natural enemies of trapdoor spiders include spider wasps from the family Pompilidae3.

Comparison Table: Trapdoor Spiders vs. Venomous Spiders

FeatureTrapdoor SpidersVenomous Spiders (Black Widow & Brown Recluse)4
SizeMedium to LargeSmall to Medium
ColorBrown or BlackBlack (Black Widow) / Brown (Brown Recluse)
VenomNot significantMedically significant
DistributionEastern & Southwestern U.S.Widespread in the U.S.

Behavior and Habitat

Feeding Habits

Trapdoor spiders primarily feed on insects and other small invertebrates.

They use their silk-lined, underground burrows as a hunting ground by waiting for prey to pass by, then quickly capturing them.

Unique Adaptations

  • Camouflage: Trapdoor spiders blend in with their surroundings, making it difficult for predators and prey to detect them.
  • Burrow Construction: They create well-structured burrows with a hinged “door” made of silk, soil, and debris that conceals the entrance from potential threats.
  • Speed and Stealth: These spiders have excellent reflexes, allowing them to capture prey and avoid danger quickly and silently.
FeatureTrapdoor SpiderBrown Recluse Spider
PoisonousNoYes
HabitatUnderground BurrowsIndoors and Outdoors
Unique AdaptationsCamouflaged Burrow EntrancesViolin-shaped Marking

Trapdoor spiders are not to be confused with brown recluse spiders, which are venomous and can pose a threat to humans.

You can learn more about different types of spiders, including venomous ones like the brown recluse, by visiting the CDC website.

Male Brown Recluse Spider

Conservation and Human Impact

Threats and Conservation Efforts

Trapdoor spiders have faced challenges such as habitat loss and pesticide exposure. These factors contribute to their population decline.

Conservation efforts include habitat preservation and raising public awareness about the importance of these spiders in nature:

  • Enhancing natural habitats
  • Encouraging sustainable land management
  • Educating the public on the ecological roles of spiders

Role in Pest Control

Trapdoor spiders play a significant role in controlling insect populations.

They help maintain balance in the ecosystem by feeding on insects. Some benefits of their pest control efforts include:

  • Reducing the number of pests that can harm crops
  • Controlling insects that carry diseases
  • Limiting the need for chemical pesticides

Comparison Table: Trapdoor Spiders vs. Chemical Pesticides

FeatureTrapdoor SpidersChemical Pesticides
Cost-effectiveYesNo
Eco-friendlyYesNo
Human health impactLowHigh
Effect on biodiversityPositiveNegative

Overall, trapdoor spiders provide valuable natural pest control services, and their conservation benefits both our environment and human health.

Trapdoor Spider

Conclusion

Overall, trapdoor spiders use their venom to paralyze prey, but they usually pose little danger to humans.

Venom potency varies among species, causing mild discomfort and pain.

Understanding specific species is key.

For instance, the Sydney funnel-web spider’s venom can be life-threatening, while North American trapdoor spiders like Ummidia audouini have less concerning venom, causing slight itchiness.

Educating yourself about toxicity levels is crucial for safety and easing fears around these creatures.

Footnotes

  1. (https://arthropod.uark.edu/trapdoor-spider/ 2 3 4
  2. (https://entomology.wsu.edu/outreach/bug-info/jumping-spider/
  3. (https://extension.msstate.edu/newsletters/bug%E2%80%99s-eye-view/2021/trapdoor-spider-vol-7-no-28
  4. (https://www.cdc.gov/niosh/topics/spiders/default.html

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about trapdoor spiders. Scroll down to have a look at some of them.

Letter 1 – California Trapdoor Spider: Male Spiders emerge with the rain

2 inch black spider with brown abdomen
October 15, 2009
This spider crawled over my wife’s foot. It’s about 2 inches long, shiny black with a brown slightly furry abdomen.

It’s mid October here in LA and we just had a rather large rainstorm, the first of the season, possibly it tried to escape into the house? We let him go right after we took the picture.
Syd
Los Angeles California

Male California Trapdoor Spider
Male California Trapdoor Spider

Hi Syd,
This is a male California Trapdoor Spider, Bothriocyrtum californicum.  Each year, the first rains of the season trigger the mating instinct of the male California Trapdoor Spider who leaves his burrow and wanders in search of a mate.  This species is sexually dimorphic. 

Sadly, the male spiders often wander into backyard swimming pools and drown.  Interestingly, our Mount Washington Los Angeles neighbor Jeanie left a tupperware on our porch last night.  There is a male California Trapdoor Spider in that tupperware. 

We were waiting for morning light to take our own photo to create a posting.  According to Charles Hogue, in his awesome Insects of the Los Angeles Basin, “Trapdoor spiders are novelties in the Los Angeles Basin today, although they were commonplace a few years ago. 

They were even collected and sold as curios in the Los Angeles area at the beginning of the twentieth century.  Their rarity now is another example of human expansion destroying the habitat of a local animal. 

The spider prefers to build its nest on sunny south-facing dry hillsides, which in the spring bear a thick covering of short grasses and low herbs.  Such areas are becoming increasingly rare in the basin (they are also the habitat of our local tarantulas, and both types of spiders can be found living on the same hillsides).”

Male California Trapdoor Spider
Male California Trapdoor Spider

Letter 2 – Another Male California Trapdoor Spider

Trapdoor Spider
October 17, 2009
My wife found this spider in our kitchen sink. She was too scared to pick it out even though it was dead. After picking it out I was fascinated by its size. My question is if this spider is dangerous/venomous? Thank You.
Erik T.
Mount Washington, Los Angeles

California Trapdoor Spider
California Trapdoor Spider

Hi Erik,
Thanks for informing us about another Mount Washington sighting of a Male California Trapdoor Spider.  All spiders have venom, but only a few are harmful to humans.  Either the venom is too mild or is not of sufficient quantity, or the fangs of the spider cannot penetrate human skin. 

We know of no reports of anyone being bitten by a California Trapdoor Spider, but that does not mean it cannot happen.  The California Trapdoor Spider is not a species that is considered harmful to humans. 

We are happy to hear that there must still be a healthy population of this magnificent spider in the Mount Washington area where continued development is reducing the amount of open space.

Letter 3 – Brush Footed Trapdoor Spider from Australia

Male Brush Footed Trapdoor
Location: Queensland Au
October 21, 2010 12:22 am
Hi Guys,
We have been having heaps of rain down here and it bought this stunning male Brush Footed Trapdoor (Idiommata iridescens) to my back verandah. I didn’t find out till I got an ID that it is highly venomous in the same sort of toxicity as our infamous Sydney Funnel Web.
Signature: aussietrev

Brush Footed Trapdoor Spider

Hi Trevor,
Thanks for sending us another excellent photo of an unusual Australian species.  We had not heard of any highly venomous Trapdoor Spiders, so we decided to do a bit of internet sleuthing to find some information. 

Our first hit, the Find A Spider Guide for the Spiders of Southern Queensland, produced your very photograph.  Not much else of any use turned up.

Letter 4 – California Trapdoor Spider

California Trapdoor Spider (photos)
Location:  Mt Washington, Los Angeles, CA
October 20, 2010 12:16 pm
Last night I found what I believe to be a California Trapdoor Spider climbing the wall near my front porch.  As it’s unusual to see such a huge spider in our area I captured it rather than killing it so it could be relocated to a more suitable location. 

I thought I would share the photos as the one of it’s relocation shows it in pretty good detail and color.  Enjoy!
~ Chris

California Trapdoor Spider

Hi Chris,
We really love California Trapdoor Spiders.  You did not indicate where you live, but since our offices are in Los Angeles, we know all about the unseasonal rains that have been falling for several days now. 

Male California Trapdoor Spiders wander about in search of a mate after the first rains of the season.  Sadly, many wander into swimming pools and drown.  We are happy you rescued this guy and released him.  Hopefully he will get lucky and perpetuate the species.

Hi Daniel,
I did forget to include that!  I live at the base of Mt. Washington at the L.A./Eagle Rock border.  I’m about 2 miles from the ‘wild’ area of the mountain so I imagine this guy either got washed out or hitched a ride down as there isn’t a good habitat for him in my immediate area. 

He’s been happily relocated back to the Heidelberg Park area of the mountain and should find plenty to keep his attention up there!  Feel free to use either of the photos I linked on your website if they will work for your purpose.  Thanks for maintaining a good resource on the CTS!
Chris

Hi Chris,
Thanks for the additional information.  Daniel lives in Mt Washington near Elyria Canyon, so it appears we are neighbors.

Authors

    by
  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

36 thoughts on “Are Trapdoor Spiders Poisonous? Unveiling the Truth”

  1. I just had one of these crawl out of my shower drain while i was taking a shower. scared me half to death! i decided to look online to see what it was…im glad its not poisonous!

    Reply
  2. Hi guys,
    Unfortunately most Australian spiders have very little information available about them on the internet. The details re the toxicity come from a book ‘A Guide to Australian Spiders by Densy Clyne’ who refers to an 1870 study of the species.
    Trevor

    Reply
  3. I live in Silver Lake (LA) & found one floating in my pond this morning. I thought it was dead, and removed it to photograph it. A couple hours later, it started walking away! Checking online, I see it’s definitely a CA Trapdoor Spider. I will release it in the vacant lot next door.

    Reply
    • Since Southern California is bracing for a five day storm predicted to be the worst in a decade, we hope your rescued California Trapdoor Spider manages to find a safe retreat.

      Reply
  4. I have spotted two of these guys across Eagle Rock Blvd from Mt Washington in Glassell Park over the past 2 months. Glad to know they’re not poisonous!

    Reply
    • Hi mchin,
      Most spiders, including the California Trapdoor Spider are venomous, however in the unlikely event that they bite a human, the bite is not considered dangerous.

      Reply
  5. we lived at 973 figueroa terrace los angeles in the 60’s…..we had many visits from
    USC professors looking for trap door spiders…there were huge colonies living behind our house !!

    Reply
    • Alas, development in the Mount Washington area has eliminated much of the native habitat for Trapdoor Spiders that seem to prefer sunny, south facing slopes with sandy soil.

      Reply
  6. we lived at 973 figueroa terrace los angeles in the 60’s…..we had many visits from
    USC professors looking for trap door spiders…there were huge colonies living behind our house !!

    Reply
  7. The type locality of the trapdoor Bothriocrytum californicum is Inglewood, CA. I observed trapdoors for years. Their doors can open in any direction, they were once abundant on flat ground, without plant cover, directly across the street from my Inglewood home. A Newport Bay report stated that their burrows were vertical. Actually their burrows are gently curved in an “S”- shape expanding at the ending–none are actually vertical.

    Reply
    • Dear John,
      Thank you so much for your firsthand knowledge of California Trapdoor Spiders, a truly magnificent species. We are saddened that their numbers are dwindling due to habitat loss.

      Reply
  8. I found a live male CA trapdoor spider in our shower on Sunday (we live in Corona CA). I asked my husband to catch and remove him, but he said he was gone. I just found him again this morning – he’s apparently been hiding under the soap dish. My husband has a new to-do when he gets home. Hopefully he’ll find a sunny place for him.

    Reply
    • Thanks so much for taking the time to relocate your California Trapdoor Spider. Their numbers have dwindled in most urban areas where they formerly ranged.

      Reply
  9. Hey Guys,

    I just had a CA TDSpider try to hide in my shirt collar. I found him when getting ready for work. I live in Pacific Grove, CA and was scared it was a Brown Recluse. Glad you all had pic posted here!

    Reply
    • Did you forget to hang up your clothes? We don’t believe a California Trapdoor Spider would climb into the closet and settle into the clothes on hangers, or even the clothes in drawers, but clothes left on the ground might provide a secure resting place.

      Reply
  10. I found a California trapdoor spider on the bottom of my stairs on the way to my laundry room…He looked dead ants were on him but it didn’t look like they were eating him! I flipped him periodically through out the day to take pictures, Finally I felt so sad to see the ants surrounding my husband got a paper and through him on the hillside, Reading up on him, I wonder why he left his trap to die? It was raining the prior day although that was a weird spot for him to pass on! He was beautiful!

    Reply
  11. We just found one in my front yard. Thought it was a baby tarantula, till I did research and found out it was a male california trap spider. Interesting stuff!

    Reply
  12. My mom and i found two of these in a tarp puddle and we have never seen them before. I thought they were dead but i was so wrong..i read up on these spiders and im curious, what are they in eugene oregon for if they are meant to be in warm weather? Theres no sign anywhere where we live of their nests either

    Reply
    • Without an image, we are unable to comment on the spiders you encountered. There are species of Trapdoor Spiders in Oregon, and though BugGuide does not report any sightings of California Trapdoor Spiders outside of California, it is possible that the range is greater than what is reported.

      Reply
  13. I found a dead one just outside my front door today in Highland Park…the little stinker in me was SOOO tempted to leave it on my mate’s pillow…my arachnophobic mate….LOL…a divorce would be next so I decided against it.

    Reply
  14. Saw three of these spiders in Oceanside/Vista area yesterday after heavy rain ..
    There was very hot weather before the rain.
    Sept 15, 2015… Must be a healthy species here… I live on the land an old large nursery..

    Reply
  15. Saw three of these spiders in Oceanside/Vista area yesterday after heavy rain ..
    There was very hot weather before the rain.
    Sept 15, 2015… Must be a healthy species here… I live on the land an old large nursery..

    Reply
  16. Very common up here in the California San Bernardino Mountains, We even had a good sized female build a home under our bathroom sink… (she was relocated) Folks up here are constantly posting pics of the CTDS on local FB pages asking what they are…so I educate them when I can…

    Reply
  17. I found a CTD spider in Lakeside CA at Walmart in the parking lot right after hard rain then drizzled ..this guy( CTD spider )was walking in the parking lot I scooped him up brought him home and I will release him on the mountain side I live by so hopefully he can mate and live on….

    Reply
    • It is our experience that many large insects meet cruel fates in parking lots. Stomping feet tend to do more damage than getting run over by cars. Your actions may have saved the life of a Trapdoor Spider.

      Reply
  18. Oh my goodness, feel so bad! Last night we came across 5 of them and killed them, they were so scary looking I thought they were deadly! So glad I looked them up, at least now I know. Last night I searched online but nothing came up.

    Reply
    • Finding so many after a good rain is an indication you have a healthy population. Male Trapdoor Spiders often die while searching for a mate. We hope in the future you will be more tolerant of these incredible spiders.

      Reply
  19. One was just crawling across my bedroom floor in Highland Park (Los Angeles), it rained yesterday for the first time in ages. I have him in a big jar. Where is the best place I can release hopefully away from my house?

    Reply
    • You might consider the hill between Highland Park and Eagle Rock, where Avenue 51 becomes Townsend, which is Occidental College property. This is open space that will not be developed.

      Reply

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