The ravine trapdoor spider is an intriguing creature, belonging to the family Ctenizidae and typically found in underground burrows. These spiders are known for their unique behavior of creating silk-lined trapdoors, a feature that allows them to catch their prey with ease as they wait for unsuspecting victims to approach their hidden lair.
Trapdoor spiders, like the ravine trapdoor spider, are distributed across the United States, particularly in the East and Southwest regions, with around 50 species belonging to the most speciose genus, Ummidia. These spiders have a variety of adaptations to suit their burrow-dwelling, ambush predator lifestyle, such as strong front legs and a specialized jaw structure to quickly capture prey.
Ravine Trapdoor Spider Basics
The Ravine Trapdoor Spider (Cyclocosmia truncata) belongs to the Ctenizidae or Halonoproctidae family. This unique spider has a distinctive abdomen that acts as a protective shield.
- Size: Smaller than some other spider species, with a body length around 0.31-0.47 inches (8-12mm)
- Color: Mostly brown or black
- Eyes: They have eight eyes as most spiders do, but their arrangement may vary
- Abdomen: The abdomen is flattened and has a hard, disk-like appearance, resembling a shield
- Legs: Long, hairy legs, with the front pair usually larger and more robust than the others for assisting with digging
Distribution and Habitat
The Ravine Trapdoor Spider inhabits various regions across North America. They are typically found in areas with loose, well-draining soil, as they create silk-lined burrows with a trapdoor-like entrance. They are known to reside in wooded areas and along ravines, hence their name.
Comparison of Trapdoor Spider Families:
|Around 0.51-1.97 inches (13-50mm)
|Similar to Ctenizidae
|Widespread in the East and Southwest North America
|Various habitats, including grasslands and forests
|Similar to Ctenizidae
These spiders are ambush predators that spring out of their burrows when prey goes near their trapdoor entrance. They rarely venture far from their burrow and are not considered dangerous to humans.
Life and Behavior
Burrowing and Trapdoors
The ravine trapdoor spider creates a unique home called a burrow, which is a silk-lined tunnel in the ground. The burrow entrance is covered by a hinged door, also made from silk. This door camouflages the spider against predators and helps it catch prey.
- Trapdoor made from silk
- Hinged door for camouflage
These spiders prefer damp habitats like riverbanks and forests. They are commonly found in Alabama, Georgia, and Tennessee.
Diet and Hunting
Ravine trapdoor spiders are predators with a diet mainly consisting of insects. A common prey for them is the cricket. They hunt by waiting in their burrow with their trapdoor slightly open. When an unsuspecting prey comes close, they quickly capture it.
Reproduction and Lifespan
Mating occurs near the female’s burrow, where the male ventures to find a mate. After successful mating, the female produces an egg sac inside her burrow.
- Female lifespan: up to 12 years
- Males lifespan: shorter than females
|Up to 12 years
Overall, the ravine trapdoor spider is an intriguing species with interesting habits and skills like their burrowing techniques, diet and hunting strategies, and reproduction methods.
Predators and Threats
Parasitic Wasps and Other Natural Enemies
Ravine trapdoor spiders are prey to certain arthropods, particularly, parasitic wasps. These wasps lay their eggs on or near the spider’s burrow, and upon hatching, the larvae feed on the spider.
Some other natural enemies of the ravine trapdoor spider include:
These insects may target the spiders as prey, particularly during the night when the arachnids are more active.
Human activity is another threat facing ravine trapdoor spiders. Their habitat in Mexico, which ranges from black to dark brown, is often disrupted by construction, deforestation, and pollution. Additionally, some people may accidentally or intentionally harm these spiders due to fear or misinformation.
Comparison Table: Ravine Trapdoor Spider Predators and Threats
|Lay eggs near spider’s burrow; larvae consume spider upon hatching
|May prey on spiders during the night
|May also target spiders as prey
|Habitat disruption and harm due to fear or misinformation
Overall, the ravine trapdoor spider faces both natural enemies and human-related threats, making its survival a complex challenge.
Identification and Observations
Finding Ravine Trapdoor Spiders
Ravine trapdoor spiders can be found in areas such as ravines, hilly regions, and shaded slopy areas, particularly in southeastern China. They prefer moist, sandy soil, which provides ideal conditions for their burrows. Some examples of their habitat include environments like northern Florida and southern Georgia in the United States.
- Body length: Ravine trapdoor spiders typically have a body length of around 1-2 inches (2.5-5 cm).
- Distribution: These spiders are mainly distributed throughout southeastern China, while certain regions of the United States, including northern Florida and southern Georgia, can also harbor some populations.
Here is a comparison of ravine trapdoor spider characteristics and their preferred habitat:
|Ravine Trapdoor Spiders
|Southeastern China, Northern Florida, Southern Georgia
|Ravines, hilly regions, shaded slopy areas
|Moist, sandy soil
It’s essential for humans to take care when exploring or living in areas inhabited by ravine trapdoor spiders. Although they are not considered dangerous to humans, their presence should be noted. Spiderlings, for example, can still be a potential irritant if they come into contact with people.
Ravine Trapdoor Spider as Pets
Care and Management
Location: Ravine trapdoor spiders are found in the eastern United States and prefer living in wooded areas with abundant leaf litter.
Enclosure: These arachnids require a spacious terrarium containing moist soil, hiding spots, and leaf litter. Make sure to provide a tight-fitting lid, as they can escape from small openings.
Feeding: In captivity, feed them once a week with insects such as crickets or locusts.
Bite and venom: Although not highly venomous, their bites can be painful, but are rarely dangerous. Nonetheless, it’s still important to be cautious when handling them.
Non-aggressive nature: They are generally non-aggressive, but may become defensive if they feel threatened or stressed. It’s best to limit handling as much as possible.
Hunting: In the wild, ravine trapdoor spiders create circular dents lined with silk and bristles to trap their prey. Captive spiders may still exhibit this behavior, so ensure they have proper substrates to do so.
|Ravine Trapdoor Spider
|Common Pet Tarantula
Caring for a ravine trapdoor spider can be an interesting and rewarding experience for dedicated enthusiasts. However, be prepared for the potential challenges and always handle them with care.
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.
Letter 1 – Male Trapdoor Spider
What is this spiderarage
I’ve run across 7 of these spiders in my garage over the last 4 years. No one ive ever shown the pictures to have any idea what kind of spiders these are. I live in Alabama & would really appreciate some help figuring out what breed of spider this is.
In photo im sending you has a spider that is about the size of a large orange that is cut in half. It’s apx 4 inches across in this stance and 3-4 inches tall. When it’s legs are spread out, it is apx 6 inches in diameter. What really bothers me about these spiders are the size of their fangs, they are a true 1/2" long. Thank you in advance
This is very interesting. This sure looks like a Tarantula, and the size description fits as well. When we searched the Spiders of Alabama website, we read: “THERAPHOSIDAE Aphonopelma sp. Notes: Tarantulas of this family almost certainly do not occur in Alabama. However, Roth (1993) referred to ‘one questionable record from AL.'” We are going to check with Susan, our favorite Arachnophile to see what she thinks. Eric Eaton did write in with this information: “The ‘tarantula’ from Alabama. The image is almost certainly of a male trapdoor spider. They wander in search of mates, which is how they end up in garages and such. The size is being grossly exaggerated in all likelihood, though males certainly have a larger legspan than females. Eric ”
Update: (06/16/2007) tarantula? from Alabama???
First off: is this the best and the only image you have? Does the original have more dpi? As you know, I am not at all a spider expert. This image has no indication of scale and the background looks as is if is could be concrete very highly magnified. Just my impression, but this image does not look to me like a really big spider, and to me the spider does not really look like a tarantula. The ‘stance’ does not look correct for an athletic sort of spider that travels around a lot, and the abdomen appears not to be furry. Could it be a trap door spider maybe? Or could it even be some other spider that is quite small but the image is enlarged a lot? As far as actual or presumed Tarantulas go, there is excellent info from the American Tarantula Society website at http://atshq.org/articles /found.html “There are over 50 species of tarantulas native to the southwestern and central portions of the United States, including several undescribed species (unknown to science). They can be found in all or parts of (going in a circle): California, Arizona, New Mexico, Texas, Louisiana, Arkansas, Missouri, Kansas, Oklahoma, Colorado, Utah, and Nevada. Their eastern border is the Mississippi River and further to the north, the Missouri River. There is an introduced population of Brachypelma vagans in central Florida, but this species is indigenous to southern Mexico and Belize.” On that same webpage there are instructions for contacting Tarantula expert Brent E. Hendrixson at East Carolina University; Department of Biology, Howell Science Complex N404A, Greenville, North Carolina 27858 USA, email: email@example.com or phone 252 328-2971. Perhaps Chris can send the image to Brent and get Brent’s opinion? Best,
Letter 2 – Male Trapdoor Spider
Black Purseweb Spider, Atlanta area
I live in East Henry Co. Georgia. We are about 30 min. South of Atlanta. 2 years ago (2004), I saw 2 of these spiders in near proximity to one another (few yards). Upon my witness, they accidentally came into each other’s view. Both spiders "displayed" by raising their front legs and then VERY AGGRESSIVELY pounced at the same time. The battle was over in 1-2 seconds and one was dead immediately and the other died in about 30 seconds later. I kept searching the area for more, because I wanted to study a live one close-up. The rest of that year I didn’t see any more. The next year (last year) I didn’t see any either. This year, I stumbled across another! Yeah! I captured the critter, took about 20 digi photos, and let it go. Before these encounters, I never knew we had such things a Pursewebs in Georgia. These spiders are of the ancient variety. The ancient spider’s fangs protrude straight down (with a rearward curvature) opposed to fangs that curve inward toward each other. Awesome photo attached… I like this shot because the glass jar provided even lighting to show detail. (This is a pint jar. Nice sized spider!) Notice the silver markings around the joints. Unseen in this photo are the 4 small brown circles or "patches" on the underside of the abdomen. …If provoked, this spider also showed lunging aggression. Play very cautiously around these spiders.
We have devoted an entire page to the Red Legged Purseweb Spider. Also, thank you for the wonderful narrative. Eric Eaton provided us with the following identification correction: “I’m ba-a-a-ck:-) The “black purseweb spider” is actually a male trapdoor spider in the genus Ummidia. It is a great image that clearly shows the saddle-like depression on the third leg, just below the “knee” joint that distinguishes the genus from all others. It has apparently been a good year for these guys, as we have had several images on Bugguide as well.”
Letter 3 – Mygalomorph Spider from South Africa
Subject: Black spider
Location: Benoni East Rand Gauteng
March 26, 2016 1:00 am
Before we moved into our new house one night, we spoted a strange looking black spider in the house. I’ve never seen one like this before, can you tell me what this is?
This looks like a primitive Mygalomorph Spider, a member of the Infraorder Mygalomorphae, the group that includes Tarantulas and Trapdoor Spiders. We believe your individual is a Trapdoor Spider. It does not look too dissimilar from the Horned Trapdoor Spider, Stasimopus filmeri, and other members of the genus pictured on iSpot.
Letter 4 – Mexican Trapdoor Spider
Unknown big spider in coastal Oaxaca State, Mexico
Mon, Mar 16, 2009 at 11:06 AM
We found this unfortunate drowing-victim in our pool one December morning at our place in Puerto Escondido, Oaxaca, in Mexico – we’ve spent lots of time down there, but have never seen a spider like it, so maybe it only comes out at night? I couldn’t stop looking at it, it is just so cool!
The first photo is how we found it: upside down at the bottom of the pool, just thought this would be good for scale.
The next two photos are (obviously) just close-ups of the mystery spider.
Hope you can help!
Puerto Escondido, Oaxaca, Mexico
We believe this is a Trapdoor Spider. There is a related spider in California that frequently drowns in pools after the winter rains. The rains trigger the mating urge in the male Trapdoor Spider who leaves his burrow in search of a mate. Sadly, swimming pools often seem to be on the spider’s route.
Letter 5 – Male California Trapdoor Spider
Possible trapdoor spider?
Thu, Nov 27, 2008 at 3:06 PM
I found this specimen on my porch in the last stages of life. It is black and appears to have a light brown bulbous sac at one end. Also, it looks like it has ten legs. Is it a trapdoor spider perhaps?
Echo Park, Los Angeles, CA 90026
Greetings from Mount Washington, across the Los Angeles River. This is a male California Trapdoor Spider, Bothriocyrtum californicum. Thanks to human expansion into their habitat, they are becoming increasingly rarer in the Los Angeles area. During the rainy season, we would encounter male California Trapdoor Spiders searching for the burrows of prospective mates in the hills of Glassell Park when we lived there, and in our current location in Mount Washington. Your proximity to Elyssian Park is probably a contributing factor to this encounter. Charles Hogue, in his book Insects of the Los Angeles Basin, wrote: “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 … .” Just today, we pitched an article idea for our local newsletter entitled “Look What Crawled Out in the Rain” with the intention of writing about both the California Trapdoor Spider and the Potato Bug.
Letter 6 – Male California Trapdoor Spider drowns in swimming pool
Subject: 3-4 inch spider!
December 28, 2015 7:38 pm
Hello, we fished this spider out of our pool yesterday in Santee, California. I think it’s a trap door spider but it is 3 to 4 inches long and from what I’ve read they are usually much smaller. Do you think it’s possible? If not what type of spider do you think it is?
This is indeed a male California Trapdoor Spider. BugGuide does not list a size for the species, but it does provide this fascinating bit of information: “According to Guinness World Records, as of 2009, this is the strongest spider. It has been able to resist a force 38 times its own weight when defending its trapdoor. This equates to a man trying to hold a door closed while it is being pulled on the other side by a small jet plane.(1) Unfortunately, the Guinness book doesn’t mention if it’s the strongest North American spider or if it’s the strongest in the world. Also, one thing to think about is whether or not every spider’s strength has been measured (no, they most definitely have not). The information is flawed in many respects, but it still asserts the fact that these spiders are pretty strong.” In our own experience, while four inches seems a bit large, a three inch measurement is within reason for a large male, but it is also possible that drowning caused this individual to swell larger than its life size. Generally, the first sightings of the year for male California Trapdoor Spiders coincide with the first seasonal rains as the males begin searching for mates at that time. Though we were away from the office when you wrote, we understand there was some southern California rain around that time. Today though is the official arrival of El Niño rains in Los Angeles.
Thank you! Very interesting information. I appreciate you taking the time to get back to me.
Letter 7 – Male California Trapdoor Spider appears after first rain of the season
Subject: Trap door spider
Location: East Oceanside,CA
September 16, 2015 6:02 pm
Trying to send you a pic.
It would be easier to forward an email.
Can you provide one ?
I commented on your web site..
you attached an image, but it is not a spider.
Sorry I messed up the attachment on the web site..
Here is the spider we found…
Thanks for sending the correct image. We really love posting images of male California Trapdoor Spiders that appear with the first good rains of the season, and Tuesday’s downpour was a doozy.
Letter 8 – Male California Trapdoor Spider appears after Rain
Subject: Trap door?
Location: Oceanside CA
September 21, 2016 9:27 pm
Bug man think I got a trap door. What do you think?
Oceanside after the rain..
This is indeed a male California Trapdoor Spider and it appeared right on schedule, though your September rain was rather unseasonal in Southern California. It will be interesting to see how changes in our weather patterns will affect populations of native species. Male California Trapdoor Spiders wander in search of mates after the first rains of the season.
Letter 9 – Male California Trapdoor Spider found in Eagle Rock
Subject: Spider ID
Location: (North) Eagle Rock
December 17, 2013 3:41 pm
First of all, I can’t tell you enough how pleased I was to come across your site, and even more so to learn that you’re a local Angeleno!!
Can you help me identify this spider?? My first thought was a juvenile tarantula, but I’m now leaning toward a Crevice Weaver upon further research. I have lived in this area (Pasadena/Eagle Rock) my whole life and have never seen a spider this impressive. See the attached photo.
Signature: Dr. Jones
Good Morning Dr. Jones,
Greetings from Northeast Los Angeles, the best part of our city. Your first thought was actually a bit closer taxonomically, as this is a male California Trapdoor Spider, Bothriocyrtum californicum. Trapdoor Spiders are classified with Tarantulas and other primitive spiders as Mygalomorphs. Due to habitat destruction, California Trapdoor Spiders are not as common as they once were in the Los Angeles basin. They tend to live on sunny, south facing slopes, and much of the land in northeast Los Angeles that fits that description was built on over various construction booms in the past century. You are lucky to have much open space in Eagle Rock along the 134 freeway, and we expect there is a healthy population of California Trapdoor Spiders in them there hills. Sexually dimorphic Female California Trapdoor Spiders are long lived and rarely encountered as they do not leave their burrows unless forcibly evicted. Males wander in search of mates, and they are frequently encountered after the winter rains begin. Sadly, many male California Trapdoor Spiders fall into swimming pools and drown. BugGuide does provide this interesting bit of trivia: “According to Guinness World Records, as of 2009, this is the strongest spider. It has been able to resist a force 38 times its own weight when defending its trapdoor. This equates to a man trying to hold a door closed while it is being pulled on the other side by a small jet plane!(1) Unfortunately, the Guinness book doesn’t mention if it’s the strongest North American spider or if it’s the strongest in the world. Also, one thing to think about is whether or not every spider’s strength has been measured. I guess one can safely say that the information is flawed in that aspect, but it still asserts the fact that these spiders ARE very strong.”
Letter 10 – Male California Trapdoor Spider in Mount Washington
Came by with a specimen that came waltzing into my studio. It graciously allowed me to catch it, although I don’t know how much air it will need…it’s in a Tupperware container on your porch…
WHAT’S THAT SPIDER?!?!?
Last night, we arrived home from work to find a food container on the front porch with this gorgeous male California Trapdoor Spider, Bothriocyrtum californicum, inside. Seems our Mount Washington neighbor had him wander into her backyard studio which we learned upon checking our email. The unseasonal October rains have triggered the mating instinct of the male California Trapdoor Spiders and is causing them to wander about in search of mates. After posing for this photo this morning, we are releasing this randy guy in a vacant lot around the corner.
Letter 11 – Male California Trapdoor Spider wandering after the rains
Subject: california trapdoor spider trapped
Location: Arroyo seco, Los Angeles, CA
November 19, 2012 12:08 am
this little guy wandered into my house, is there anyone I should take this to? I Will probably release it tomorrow into the wild. I am in the Hermon/Highland park are of Los Angeles.
Greetings from nearby Mount Washington. Male California Trapdoor Spiders, Bothriocyrtum californicum, begin to wander about after the first rains of the season because they are searching for mates, so his appearance is right on time. The best place to release him is an open south facing slope. We would recommend taking it to Ascot Hills Park near El Sereno which is a lovely open space park. Habitat destruction is responsible for diminishing numbers of California Trapdoor Spiders in the Los Angeles area. For your good deed, we are tagging your post with the Bug Humanitarian Award, and your post will go live later in the week as we are preparing to be away from the office for several days for Thanksgiving.
Letter 12 – Male Trapdoor Spider
Large Black Spider
I spotted this large black spider walking along a dry cornfield in southern Maryland. I think it’s a species of wolf but not sure. Can you help?
A Photographic Journey of the Outdoor World
This is a male Trapdoor Spider in the genus Ummidia. When conditions are right, he wanders in search of a mate. Female Trapdoor Spiders rarely leave their burrows.
Letter 13 – Male Trapdoor Spider drowns in pool
Subject: Dead spiders in my pool
Geographic location of the bug: Killeen, Texas
Time: 05:48 PM EDT
Found it dead in the pool. Just curious what it is and if me and my guests need to worry. Legs outstretched it was about 4″ from… toe to toe? And torso was around 1.75″ long.
How you want your letter signed: Mike
This is a male Trapdoor Spider, probably in the genus Ummidia, and they are not aggressive. Male Trapdoor Spiders wander in search of a mate and males are frequently found drowned in pools.